The document outlines the fundamental characteristics that define living organisms, including nutrition, respiration, and reproduction. It categorizes the main groups of living organisms—plants, animals, fungi, bacteria, protoctists, and viruses—detailing their unique features and examples. Additionally, it discusses the hierarchical organization within organisms, emphasizing the structure and function of cells and their components.

1. IT’S ALIVE !!!!
1.1 Understand that living organisms share the following characteristics: they require nutrition; they respire; they excrete their waste; they respond to their
surroundings; they move; they control their internal conditions; they reproduce; they grow and develop.
M Movement All living things move, even plants
R Respiration Getting energy from food
S Sensitivity Detecting changes in the surroundings
G Growth All living things grow and develop
R Reproduction Making more living things of the same
type (species).
E Excretion Getting rid of waste
N Nutrition Taking in and using food and other
nutrients
In addition, all living organisms contain nucleic acids (DNA/RNA) and
have the ability to control their internal conditions (homeostasis).
Finally, all living organisms can die.

2. ALIVE OR NOT ALIVE!!
ALIVE OR NOT ALIVE
1.1 Understand that living organisms share the following characteristics: they require nutrition; they respire; they excrete their waste; they respond to their
surroundings; they move; they control their internal conditions; they reproduce; they grow and develop.

3. GROUPS OF LIVING ORGANISMS
1.2 describe the common features shared by organisms within the following main groups: plants, animals, fungi, bacteria, protoctists and viruses, and for each
group describe examples and their features as follows (details of life cycle and economic importance are not required)

4. PLANTS
Plants: These are multicellular organisms; their cells contain chloroplasts and are able to carry out photosynthesis; their cells have cellulose cell walls; they
store carbohydrates as starch or sucrose
Plants all have the following in common:
1) Multicellular organisms (made of lots of cells)
2) Cells contain chloroplasts and are able to carry out photosynthesis.
Photosynthesis takes simple inorganic molecules and turns them into
simple sugar (glucose). Glucose can be turned into complex organic
molecules such as carbohydrates.

5. PLANTS
Plants: These are multicellular organisms; their cells contain chloroplasts and are able to carry out photosynthesis; their cells have cellulose cell walls; they
store carbohydrates as starch or sucrose
3) Cells have cellulose cell walls (cellulose is a
carbohydrate)

6. PLANTS
Plants: These are multicellular organisms; their cells contain chloroplasts and are able to carry out photosynthesis; their cells have cellulose cell walls; they
store carbohydrates as starch or sucrose
4) They store carbohydrates as starch.
Carbohydrates are polysaccharides (many sugars/glucose linked
together)
or sucrose.
Sucrose is a disaccharide (two sugars linked together).

7. Examples you need to know:
1) flowering plants, such as a cereals
A) Maize
PLANTS
Examples include flowering plants, such as a cereal (for example maize), and a herbaceous legume (for example peas or beans)
B) Wheat

8. PLANTS
Examples include flowering plants, such as a cereal (for example maize), and a herbaceous legume (for example peas or beans)
2) Herbaceous legume (e.g. peas or beans).
Root nodules

9. ANIMALS
Animals: These are multicellular organisms; their cells do not contain chloroplasts and are not able to carry out photosynthesis; they have no cell walls; they
usually have nervous coordination and are able to move from one place to another; they often store carbohydrate as glycogen
1) Animals include:
sponges, molluscs, worms, starfish, insects, crustaceans,
fish, amphibians, reptiles, birds, mammals
Animals without a backbone (vertebral column) are invertebrates.
Animals with a vertebral column are called vertebrates.
2) Animals are Multicellular organisms

10. ANIMALS
Animals: These are multicellular organisms; their cells do not contain chloroplasts and are not able to carry out photosynthesis; they have no cell walls; they
usually have nervous coordination and are able to move from one place to another; they often store carbohydrate as glycogen
3) They have a nervous system
4) They often store carbohydrate as glycogen in the
liver and muscles.

11. ANIMALS
Animals: These are multicellular organisms; their cells do not contain chloroplasts and are not able to carry out photosynthesis; they have no cell walls; they
usually have nervous coordination and are able to move from one place to another; they often store carbohydrate as glycogen
5) Animal cells do not contain chloroplasts and are
not able to carry out photosynthesis
6) Animal cells have no cell walls

12. ANIMALS
Animals: These are multicellular organisms; their cells do not contain chloroplasts and are not able to carry out photosynthesis; they have no cell walls; they
usually have nervous coordination and are able to move from one place to another; they often store carbohydrate as glycogen

13. ANIMALS
Examples include mammals (for example humans) and insects (for example housefly and mosquito)
Examples you need to know:
1) Human (mammal)

14. 2) Insects
Examples include mammals (for example humans) and insects (for example housefly and mosquito)
a) Housefly
ANIMALS
Why the housefly?
- They regurgitate stomach enzymes onto their food
- but also because other flies are interesting
A) Tsetse fly
B) Screw fly
C) Drosophila

15. ANIMALS
Examples include mammals (for example humans) and insects (for example housefly and mosquito)
Lastly….. the use of flies ended the belief in the
spontaneous generation of life

16. Examples include mammals (for example humans) and insects (for example housefly and mosquito)
b) Mosquito
ANIMALS
Video
Bite
So why the Mosquito? (it is really just another fly!)
- Complex life cycle
- Can be a vector for malaria, yellow fever, abrovirus
- Control measures have damaged ecosystems

17. FUNGI
Fungi: These are organisms that are not able to carry out photosynthesis; their body is usually organised into a mycelium made from thread-like structures
called hyphae, which contain many nuclei; some examples are single-celled; their cells have walls made of chitin; they feed by extracellular secretion of
digestive enzymes onto food material and absorption of the organic products; this is known as saprotrophic nutrition; they may store
carbohydrate as glycogen
Characteristics of Fungi:
1) They feed by saprophytic nutrition (feeds on dead
organic material & digestion takes place outside the
organism.
2) Fungi feed by excreting extracellular secretions of
digestive enzymes onto food and absorbing the digested
products.
3) Cells are joined together to form threads, called hyphae.
Hyphae contain many nuclei, because they are made
from many cells.
4) Hyphae join together to make a network of threads called
mycelium

19. FUNGI ARE NOT PLANTS
5) Cells do not contain chloroplasts and are not able
to carry out photosynthesis
6) Cell walls are made from a protein called chitin
(not cellulose)
7) They store carbohydrates as glycogen
(not starch)
FUNGI
Fungi: These are organisms that are not able to carry out photosynthesis; their body is usually organised into a mycelium made from thread-like structures
called hyphae, which contain many nuclei; some examples are single-celled; their cells have walls made of chitin; they feed by extracellular secretion of
digestive enzymes onto food material and absorption of the organic products; this is known as saprotrophic nutrition; they may store
carbohydrate as glycogen

20. FUNGI
Fungi Examples include Mucor , which has the typical fungal hyphal structure, and yeast, which is single-celled
Examples you must know:
1) Mucor (bread mold)
Why do you need to know about Mucor?
- Easy to experiment on in the lab
(temperature, moisture)
- Mucor must use energy to absorb nutrients in it’s hyphae
- Was used to produce penicillin, the first antibiotic.

21. FUNGI
Fungi Examples include Mucor , which has the typical fungal hyphal structure, and yeast, which is single-celled
2) Yeast (single celled fungi)
Why do you need to know about Yeast?
- Easy to experiment on in the lab
(temperature & sugar concentration)
- Yeast is used in the production of beer & bread

22. BACTERIA
Bacteria: These are microscopic single-celled organisms; they have a cell wall, cell membrane, cytoplasm and plasmids; they lack a nucleus but contain a
circular chromosome of DNA; some bacteria can carry out photosynthesis but most feed off other living or dead organisms
Bacteria Characteristics:
1) Made from single cells
2) Cells do not contain a nucleus. Bacteria cells have a small piece of circular DNA instead of a
nucleus (a bacterial chromosome/nucleoid).
2) Bacteria also have DNA in the form of circular plasmids
3) most gain their nutrients by saprophytic nutrition (feed off dead organisms) or by parasitic
nutrition (feed off living organisms). Some bacteria can carry out photosynthesis.
You need to know their structure:
TED

23. BACTERIA
Bacteria: These are microscopic single-celled organisms; they have a cell wall, cell membrane, cytoplasm and plasmids; they lack a nucleus but contain a
circular chromosome of DNA; some bacteria can carry out photosynthesis but most feed off other living or dead organisms
Some pretty pictures of bacteria

24. BACTERIA
Examples include Lactobacillus bulgaricus , a rod-shaped bacterium used in the production of yoghurt from milk, and Pneumococcus , a spherical bacterium
that acts as the pathogen causing pneumonia
Example you need to know:
1) Lactobacillus bulgaricus
- Used to make yogurt
- Produces lactic acid (excretes)
- Rod shaped
- Not dangerous to humans
Why Lactobacillus bulgaricus?
- It is used in how human food production
- lowers the pH of milk to inhibit harmful
to human bacterial growth

25. Examples include Lactobacillus bulgaricus , a rod-shaped bacterium used in the production of yoghurt from milk, and Pneumococcus , a spherical bacterium
2) Pneumococcus
BACTERIA
that acts as the pathogen causing pneumonia
- pathogen causes pneumonia (inflammation of one or both lungs)
- killed with antibiotics
- spherical bacteria shape
Why Pneumococcus?
- reduces surface area of alveoli
- use of antibiotics in treatment can lead to resistant
strains

26. PROTOCTISTS
Protoctists: These are microscopic single-celled organisms.
When you don’t fit in scientists drop you into the
Protoctists group!
Protoctists Characteristics:
- most are single celled (exception is seaweeds)
- Some have animal-like features - protozoa
- Some have plant-like features – algae
swim

27. PROTOCTISTS
Some, like Amoeba, that live in pond water, have features like an animal cell, while others, like Chlorella, have chloroplasts and are more like plants. A
pathogenic example is Plasmodium , responsible for causing malaria
Examples you need to know:
1) Amoeba
- protozoa
- live in pond water
- Pathogen amoeba can cause Amoebic dysentery
(kills 70,000 people every year)
Why Amoeba?
- Highlights the need for clean drinking water supplies
- Uses amoebiasis to feed (similair to phagocytosis)
eating

28. Some, like Amoeba, that live in pond water, have features like an animal cell, while others, like Chlorella, have chloroplasts and are more like plants. A
2) Chlorella
PROTOCTISTS
pathogenic example is Plasmodium , responsible for causing malaria
- ‘more’ like plants than animals
- have chloroplasts
Why Chlorlla?
- both animal and plant characteristics
- Possible food source (1940’s solution to world hunger)
view

29. 3) Plasmodium
- Protozoa
- pathogen that causes malaria
- uses a mosquito as a vector (transfer)
- not killed by antibiotics
Why plasmodium?
- it is the greatest pathogen killer!
TED
PROTOCTISTS
Some, like Amoeba, that live in pond water, have features like an animal cell, while others, like Chlorella, have chloroplasts and are more like plants. A
pathogenic example is Plasmodium , responsible for causing malaria

30. VIRUS
Viruses: These are small particles, smaller than bacteria; they are parasitic and can reproduce only inside living cells; they infect every type of living
organism. They have a wide variety of shapes and sizes; they have no cellular structure but have a protein coat and contain one type of nucleic acid, either
DNA or RNA
Viruses Characteristics:
1) Much smaller than bacteria.
1) They are not made from cells (no cellular structures)
3) Totally parasitic and reproduce inside host cells.
3) They infect every type of living cell
3) Have either DNA or RNA as genetic material
3) Have a protein coat

31. VIRUS
Viruses: These are small particles, smaller than bacteria; they are parasitic and can reproduce only inside living cells; they infect every type of living
organism. They have a wide variety of shapes and sizes; they have no cellular structure but have a protein coat and contain one type of nucleic acid, either
DNA or RNA
You just have to recognize a virus, but there are several shapes

32. VIRUS
Viruses: These are small particles, smaller than bacteria; they are parasitic and can reproduce only inside living cells; they infect every type of living
organism. They have a wide variety of shapes and sizes; they have no cellular structure but have a protein coat and contain one type of nucleic acid, either
DNA or RNA
REVIEW FROM YEAR 8

33. VIRUS
Examples include the tobacco mosaic virus that causes discolouring of the leaves of tobacco plants by preventing the formation of chloroplasts, the influenza
virus that causes gfluc and the HIV virus that causes AIDS
Examples you need to know:
1) Tobacco Mosaic Virus
- infects crop plant and prevents formation of chloroplasts
- symptoms are discoloration of leaves
Why Tobacco Mosaic Virus?
- first identification of a virus as a pathogen
(1898, Martinus W. Beijerinck)
- Genetic engineering

34. VIRUS
Examples include the tobacco mosaic virus that causes discolouring of the leaves of tobacco plants by preventing the formation of chloroplasts, the influenza
virus that causes gfluc and the HIV virus that causes AIDS
2) Influenza Virus
- Viral pathogen causes the flu
- Transmitted through air/ contact
Why the Flu?
- Pandemics (spanish flu)
- Mutations leading to new strains
- Vaccinations
vaccine
Flu
History

35. Just thought you would like to know.

36. 3) HIV (human immunodeficiency virus)
- Pathogen causes AIDS (acquired immunodeficiency syndrome)
- Virus attacks white blood cells (immune system)
- Host killed by secondary disease
- Transmitted by blood to blood contact
Why HIV?
- Immune system
- Mutations
VIRUS
Examples include the tobacco mosaic virus that causes discolouring of the leaves of tobacco plants by preventing the formation of chloroplasts, the influenza
virus that causes gfluc and the HIV virus that causes AIDS

37. PATHOGEN
1.3 recall the term gpathogenc and know that pathogens may be fungi, bacteria, protoctists or viruses.
Pathogen:
An agent that causes infection or disease, especially a
microorganism, such as a bacterium or protozoan, or
a virus.

38. LEVELS OF ORGANIZATION
2.1 describe the levels of organisation within organisms: organelles, cells, tissues, organs and systems.
Organisms are made from organizations of smaller structures. You
need to know the following hierarchy of structures.
Organelles - intracellular structures that carry out specific functions within a cell
Nucleus Chloroplast Mitochondria Ribosome Vacuole
Cells - the basic structural and functional unit from which all biological organisms are made
Neurone Skin cell Muscle
cell
Tissues - a group of specialized cells, which are adapted to carry out a specific function
Organs - a collection of two or more tissues, which carries out a specific function or functions
Organ Systems - a group of two or more organs
Phagocyte Red Blood Cell
Muscle Nerves Blood Bone Adipose (Fat)
Heart Skin Brain Artery Kidney
Pulmonary Cardiac Nervous Endocrine Skeletal

39. LEVELS OF ORGANIZATION
2.1 describe the levels of organisation within organisms: organelles, cells, tissues, organs and systems.

40. CELL STRUCTURE (PLANT & ANIMAL)
2.2 describe cell structures, including the nucleus, cytoplasm, cell membrane, cell wall, chloroplast and vacuole
You need to know the differences between plant and animal cells, the functions of the
organelles and be able to recognize them in a microscope picture or drawing.
Mircro
scope

41. CELL STRUCTURE (PLANT & ANIMAL)
2.2 describe cell structures, including the nucleus, cytoplasm, cell membrane, cell wall, chloroplast and vacuole

42. CELL STRUCTURE (PLANT & ANIMAL)
2.3 describe the functions of the nucleus, cytoplasm, cell membrane, cell wall, chloroplast and vacuole
Functions of the Organelles
(These are the basic definitions you must know)
Cytoplasm - site of chemical reactions in the cell
Cell Membrane - controls what enters / leaves the cell (selectively permeable)
Nucleus - contains nucleic acids, which code for the synthesis of specific proteins. These
proteins control all activity in the cell
Mitochondrion - site of respiration
Chloroplast - site of photosynthesis (contains chlorophyll)
Cell Wall - made from cellulose. Strengthens the cell and allows it to be turgid
Sap Vacuole - contains the cell sap. Acts as a store of water, or of sugars or, in some cases, of
waste products the cell needs to excrete. Helps keep plant cell turgid.

43. PLANTS VS ANIMALS
2.4 compare the structures of plant and animal cells.
IF YOU ARE EVER ASKED TO DRAW AND LABLE A CELL IT MUST NOT BE A GENERAL CELL,
BUT A SPECIFIC CELL
Cell
theory

44. CELL STRUCTURE (PLANT & ANIMAL)
2.2 describe cell structures, including the nucleus, cytoplasm, cell membrane, cell wall, chloroplast and vacuole
SOME SAMPLE CELL DIAGRAMS:
White blood cell
SPERM CELL
Root hair cell

45. CHEMICAL ELEMENTS OF ORGANIC MOLECULES
2.5 identify the chemical elements present in carbohydrates, proteins and lipids(fats and oils)
To be a basic organic molecule you must have:
Some have: or even
CARBOHYDRATES PROTIENS LIPIDS
Carbon Carbon Carbon
Hydrogen Hydrogen Hydrogen
Oxygen Oxygen Oxygen
Nitrogen & Sulphur

46. CHEMICAL ELEMENTS OF ORGANIC MOLECULES
2.5 identify the chemical elements present in carbohydrates, proteins and lipids(fats and oils)

47. Making Complex Organic Structures (molecules)
2.6 describe the structure of carbohydrates, proteins and lipids as large molecules made up from smaller basic units: starch and glycogen from simple sugar;
protein from amino acids; lipid from fatty acids and glycerol
Components of the main Food Groups:
The main food groups are:
1) Carbohydrate
2) Lipids (fats)
3) Proteins
DEFINITIONS:
Monomer: Single unit
Polymer: Two or more monomers
chemically combined together
All three groups are polymers made from smaller molecules known as monomers.
1) Carbohydrates are large polymer molecules made from one or more monomer
sugars.
Two carbohydrates you need to know are Starch and Glycogen. Both have glucose as
their monomer.
2) Proteins are polymers of Amino Acids (there are 20 amino acids)
3) Lipid polymers are made from one glycerol molecule and three fatty acid molecules
joined together. So lipids are made of two different types of monomers.

48. Making Complex Organic Structures (molecules)
2.6 describe the structure of carbohydrates, proteins and lipids as large molecules made up from smaller basic units: starch and glycogen from simple sugar;
protein from amino acids; lipid from fatty acids and glycerol
CARBOHYDRATE BONDS ARE CALLED:
Glycosidic Bonds

49. Making Complex Organic Structures (molecules)
2.6 describe the structure of carbohydrates, proteins and lipids as large molecules made up from smaller basic units: starch and glycogen from simple sugar;
protein from amino acids; lipid from fatty acids and glycerol
BONDS IN PROTEINS ARE CALLED:
Peptide Bonds

50. Making Complex Organic Structures (molecules)
2.6 describe the structure of carbohydrates, proteins and lipids as large molecules made up from smaller basic units: starch and glycogen from simple sugar;
protein from amino acids; lipid from fatty acids and glycerol
BONDS IN FATTY ACIDS AND GLYCEROL ARE CALLED:
Ester Bond

51. REVIEW: Glucose is a Monomer of several
Polymers
2.6 describe the structure of carbohydrates, proteins and lipids as largemolecules made up from smaller basic units: starch and glycogen from simple sugar; protein from
amino acids; lipid from fatty acids and glycerol
Carbohydrate that is the
chief form of stored
energy in plants
Carbohydrate that is the
main component of the
cell walls of most plants
Carbohydrate is stored in
the liver and muscles in
man and animals

52. Making Cellulose
(not required in your syllabus)
2.6 describe the structure of carbohydrates, proteins and lipids as large molecules made up from smaller basic units: starch and glycogen from
simple sugar; protein from amino acids; lipid from fatty acids and glycerol

53. Test for Glucose
2.7 describe the tests for glucose and starch
NEGATIVE TEST: Blue Solution (No change)
POSITIVE TEST: Colour Precipitate (Change)
Benedict’s Test:
- In test tube with 2 ml of Benedict's reagent.
- add 5-6 drops of the test carbohydrate
solution and mix well.
- Place the test tube in a boiling water bath for
5 minutes.
- Observe any change in color or precipitate
formation.
- Cool the solution.
- Observe the colour change from blue to
green, yellow, orange or red depending upon
the amount of reducing sugar present in the
test sample.
0.5% 1% 2%<x

54. Test for Starch
2.7 describe the tests for glucose and starch
NEGATIVE TEST: orange/brown Solution (No change)
POSITIVE TEST: Black Solution (Change)
Iodine Test:
- Add 2 drops of iodine solution to about 2 mL of
the carbohydrate containing test solution.
- A blue-black colour is observed which is indicative
of presence of starch.

55. Enzymes AKA Organic Catalysts
2.8 understand the role of enzymes as biological catalysts in metabolic reactions
1) Enzymes are large molecules that speed up the chemical reactions inside cells.
2) Enzymes have a specific job (break/make substances)
3) Enzymes are specific to a particular substrate (protein, carbohydrate, lipid)
4) Enzymes are a type of protein, and like all proteins, they are made from long chains of
different amino acids.
5) Enzymes are not used up in the reactions they catalyze (speed up)
6) Enzymes are affected by temperature and pH
Enzymes are BIOLOGICAL CATALYSTS

56. So What is an difference between an Inorganic Catalyst and
an Enzyme
2.8 understand the role of enzymes as biological catalysts in metabolic reactions
Hydrogen peroxide breaks down to water and oxygen
hydrogen peroxide
water + oxygen
manganese oxide
2H2O2 2H2O O2 +
The escaping oxygen causes the foaming

57. So What is an difference between an Inorganic Catalyst and
an Enzyme
2.8 understand the role of enzymes as biological catalysts in metabolic reactions
• They occur inside cells or are secreted by the cells.
• Catalase is the enzyme that catalyses the break
down of hydrogen peroxide.
Catalase

58. Naming Enzymes
2.8 understand the role of enzymes as biological catalysts in metabolic reactions
To name an enzyme in most cases just add ‘-ase’ to
the ending of the substrate.
SUBSTRATE ENZYME
Protein Protease
Lipid (fats) Lipase
Maltose (disaccharide) Maltase
Carbohydrate Amylase (it used to be called
Other special cases are:
Carbohydrase)
Specific proteases are Pepsin and Tripsin
Catalase increase the rate of H2O2 H20 + O2

59. Enzymes AKA Organic Catalysts
2.8 understand the role of enzymes as biological catalysts in metabolic reactions
Enzymes are soluble protein molecules that can speed up chemical reactions in cells. These
reactions include :
• Respiration
• Photosynthesis
• Making new proteins
For this reason enzymes are called biological catalysts.

60. Enzymes AKA Organic Catalysts
2.8 understand the role of enzymes as biological catalysts in metabolic reactions
Each enzyme will only speed up one type of reaction as the shape of the enzyme molecule
needs to match the shape of the molecule it reacts with (the substrate molecule). This is called
the lock and key model.
The part of the enzyme molecule that matches the substrate is called the active site.

61. Rates of enzyme reactions can be measured by recording the time for a
substrate to disappear or a product to appear.
trypsin
Rates of Enzymes
2.8 understand the role of enzymes as biological catalysts in metabolic reactions
protein polypeptides
white clear
Controlled variables:
•Volume and concentration of substrate (milk)
•Volume and concentration of enzyme (trypsin)
•pH (controlled by buffers)
•Temperature
WHAT KIND OF UNITS
WILL RATES OF
REACTION HAVE?

62. Temperature’s effect on Enzyme activity
2.9 understand how the functioning of enzymes can be affected by changes in temperature, including changes due to change in active site
At low temperatures, enzyme reactions are slow. They speed up as the
temperature rises until an optimum temperature is reached. After this
point the reaction will slow down and eventually stop.
The enzyme activity increases as
temperature increases because:
1) More collisions between
substrate and enzymes
2) More kinetic energy in each
collision between substrate
and enzymes
3) More successful collisions
because of 1 & 2.
The enzyme activity decreasing
as temperature increases after a
point because:
1) Enzyme’s active site starts to
change shape (denature)
Enzyme Activity against Temperature
Rate
Of
Reaction
Optimum
temperature
0 10 20 30 40 50 60 70
Temperature/oC
Enzyme is
Molecules gain denaturing
kinetic energy

63. Temperature’s effect on Enzyme activity
2.9 understand how the functioning of enzymes can be affected by changes in temperature, including changes due to change in active site
If the shape of the enzyme changes, its active site may no longer work. We say the enzyme has
been denatured. They can be denatured by high temperatures or extremes of pH. Note that it is
wrong to say the enzyme has been killed. Although enzymes are made by living things, they are
proteins, and not alive.
You can investigate the effect of temperature on the enzyme amylase using starch and iodine,
putting the mixture in water baths at different temperatures.

64. pH’s effect on Enzyme activity
2.10 understand how the functioning of enzymes can be affected by changes in active site caused by changes in pH (TA)
Enzymes and pH
Most enzymes work fastest in neutral conditions. Making the solution more acid or alkaline will
slow the reaction down. At extremes of pH the reaction will stop altogether.
Some enzymes, such as those used in digestion, are adapted to work faster in unusual pH
conditions and may have an optimum pH of 2 (very acidic) if they act in the stomach.

65. pH’s effect on Enzyme activity
2.10 understand how the functioning of enzymes can be affected by changes in active site caused by changes in pH (TA)
Raising and lowering the pH can:
• Make more hydrogen bonds or
• Break hydrogen bonds
These hydrogen bonds hold the protein’s
active site in the correct shape

66. Experiments on Enzymes: TEMPERATURE
2.11 describe experiments to investigate how enzyme activity can be affected by changes in temperature.
Amylase Iodine and Starch solution
In different temperatures.
Measuring: time for iodine test to be
negative
Yeast and glucose solution vs Temperature.
Measuring: CO2 produced (ml)
Saliva and
Starch solution
Vs temperature
Measuring:
time for iodine
test to become
negative

67. POSSIBLE CORMMS QUESTIONS TOPICS
2.11 describe experiments to investigate how enzyme activity can be affected by changes in temperature.
Enzymes are used in biological washing powders
• Proteases break down the coloured, insoluble proteins that
cause stains to smaller, colourless soluble polypeptides.
• Can wash at lower temperatures
Enzymes are used in the food industry
• Pectinase break down substances in apple cell
walls and enable greater juice extraction.
• Lactase breaks down lactose in milk into
glucose and galactose.
This makes milk drinkable for lactose
intolerant people.

68. POSSIBLE CORMMS QUESTIONS TOPICS
2.11 describe experiments to investigate how enzyme activity can be affected by changes in temperature.
Enzymes are used in seed germination
starch
embryo plant
amylase
secreted
maltose

69. Key words
catalyst catalyse protein
catalase amylase
pectinase trypsin pepsin
substrate active site product
temperature denature
enzyme
pH
optimum
lactase
protease

70. Movement into and out of a cell
DEFINITIONS
2.12 understand definitions of diffusion, osmosis and active transport
Diffusion: The net movement of the particles of a gas or a
solute from an area of high concentration to an area of low
concentration down a concentration gradient.
Osmosis: The net movement of water down a concentration
gradient from an area of high concentration of water
molecules to an area of low concentration of water molecules
across a partially permeable membrane.
Active transport: The movement of substances against a
concentration gradient and/or across a cell membrane, using
energy.

71. Movement into and out of a cell
Diffusion
2.12 understand definitions of diffusion, osmosis and active transport
Diffusion: The net movement of the particles of a gas or a solute from an area of high
concentration to an area of low concentration down a concentration gradient.
link
link

72. Movement into and out of a cell
Diffusion
2.12 understand definitions of diffusion, osmosis and active transport
In Diffusion experiments you must only change
one variable (IV), all other variables must be
controlled. Examples are:
- Temperature (increases Kinetic energy)
- Stirring (increases Kinetic energy)
- Surface area of the boundary region
- Thickness / distance molecules have to diffuse
- The size of the concentration gradient
- The surface area to volume ratio

73. Movement into and out of a cell
Osmosis
2.12 understand definitions of diffusion, osmosis and active transport
Osmosis: The net movement of water down a concentration gradient from an area of high
concentration of water molecules to an area of low concentration of water molecules across a
partially permeable membrane.
Link

74. Movement into and out of a cell
Active Transport
2.12 understand definitions of diffusion, osmosis and active transport
Active transport: The movement of substances against a concentration gradient and/or across a
cell membrane, using energy. This also requires a carrier protein in the cell membrane.
link
Chemical energy is
called ATP.

75. Movement into and out of a cell
Review
2.13 understand that movement of substances into and out of cells can be by diffusion, osmosis and active transport
In cells molecules can move through the cell
membrane by:
Diffusion:
Small molecules move directly through the cell membrane from high concentration to
low concentration. (NO ENERGY REQUIRED)
Large molecules move through facilitated diffusion using protein channels from high
concentration to low concentration. (NO ENERGY REQUIRED)
Osmosis:
Water moves from high concentration to low concentration directly through the cell
membrane. (NO ENERGY REQUIRED)
Active transport:
Moves molecules and Ions through the cell membrane from low concentration to high
concentration. (ENERGY REQUIRED, CARRIER PROTEIN REQUIRED)

76. TURGID CELLS
2.14 understand the importance in plants of turgid cells as a means of support (TA)
EXAMINATION POINTS (step by step)
(4 Mark Question)
1) Plant cells are normally turgid (swollen full of water).
2) This is important because it provides strength to plants (rigidity).
3) Plant cells have a cell wall to stop them bursting when turgid.
4) When plant cells start to lose water they become flaccid.
5) Flaccid plants lose their strength and start to wilt.
6) Eventually, flaccid cells become plasmolysed as the cell membrane begins to peel
away from the cell wall.
7) This kills the cell.

77. RBC Example (not in syllabus)
2.14 understand the importance in plants of turgid cells as a means of support (TA)

78. Variables affecting movement into and out of cells
2.15 understand the factors that affect the rate of movement of substances into and out of cells, to include the effects of surface area to volume ratio,
temperature and concentration gradient
VARIABLES THAT AFFECT MOVEMENT RATE OF SUBSTANCES INTO AND
OUT OF CELLS:
1) Temperature
• As temperature increases movement increases
• Eventually increased temperature ruptures the plasma membrane &
denatures the enzymes
• killing the cell.
2) Concentration Gradient
• The higher the concentration gradient of a substance the faster the
rate of diffusion
• This is only if the substance can cross the plasma membrane
(osmosis/water)
3) Surface area/Volume ratio
• (Next slide please)

79. Variables affecting movement into and out of cells
2.15 understand the factors that affect the rate of movement of substances into and out of cells, to include the effects of surface area to volume ratio,
temperature and concentration gradient
If the surface area to volume ratio is too small
1) Living cell can not get nutrients for
respiration and growth.
2) Living cells can not remove waste before
toxins build up.
3) Cell size is limited by diffusion.

80. Variables affecting movement into and out of cells
2.15 understand the factors that affect the rate of movement of substances into and out of cells, to include the effects of surface area to volume ratio,
temperature and concentration gradient
WHAT IS THE SURFACE
TO VOLUME RATIO’S
FOR THESE TWO
CELLS?

81. Variables affecting movement into and out of cells
2.15 understand the factors that affect the rate of movement of substances into and out of cells, to include the effects of surface area to volume ratio,
temperature and concentration gradient
CORMMS QUESTION: Design an experiment that shows how
the surface area to volume ratio affects diffusion in agar
cubes using a solution of Phenolphthalien (a type of dye).
C:
O:
R:
M:
M:
S:

82. Experiments on Diffusion and Osmosis
2.16 describe experiments to investigate diffusion and osmosis using living and non-living systems.
Good examples of diffusion are:
- Ink chromatography
- The diffusion of KMnO4 crystals (purple) into water
- Diffusion of gases in the lung
- Diffusion of gases in the leaf
- Gas diffusion of Bromine gas
Osmosis can be shown by:
- Artificially using visking tubing
- Potato chips in salt solutions of different concentrations.

83. NUTRITION
(Yum Yum Yum)

84. PLANT NUTRTITION
2.17 describe the process of photosynthesis and understand its importance in the
conversion of light energy to chemical energy
Nutrition in Plants:
Plants are photoautotrophic (i.e. they generate
their own “food” using energy from the Sun.) They
do this through photosynthesis.

85. Photosynthesis Equation
2.18 write the word equation and the balanced chemical symbol equation for photosynthesis
Nutrition in Flowering Plants:
The equation for photosynthesis can be written as:
-Word equation
-Chemical equation
In both cases reaction uses a catalyst (chlorophyll)

86. Light ….. Glucose….. ?
2.18 write the word equation and the balanced chemical symbol equation for photosynthesis
Through photosynthesis light energy is converted
into chemical energy in the bonds in glucose. Plants
use glucose for the following;
1) Respiration
2) Stored as Starch
3) Turned into Cellulose (cellulose is a
polymer of glucose)
4) Used to make fats and oils

87. Photosynthesis Rate
2.19 understand how varying carbon dioxide concentration, light intensity and temperature affect the rate of photosynthesis
At any point the rate of photosynthesis can be
increased by adding:
1) More CO2
2) More light
WAIT!!!!
3) Heating towards optimum temperature
This (photosynthesis is not is catalyzed the by whole
enzymes).
story

88. Limiting Factors
2.19 understand how varying carbon dioxide concentration, light intensity and temperature affect the rate of photosynthesis
a)At a certain point the addition of MORE
(light & CO2) will not increase the rate of
photosynthesis any further.
b)This is because a second factor is limiting
the rate of photosynthesis.
c)Adding more of the rate-limiting factor
will increase the rate further until another
factor becomes limiting.

89. Drawing the Graph
2.19 understand how varying carbon dioxide concentration, light intensity and temperature affect the rate of photosynthesis
The addition of MORE (light & CO2) will
not increase the rate of photosynthesis
after reaching a rate limiting factor.
What about Temperature?

90. ?Temperature?
2.19 understand how varying carbon dioxide concentration, light intensity and temperature affect the rate of photosynthesis

91. ?Temperature?
2.19 understand how varying carbon dioxide concentration, light intensity and temperature affect the rate of photosynthesis
Without enough light, a plant cannot
photosynthesize very quickly, even if there is
plenty of water and carbon dioxide.
1) Increasing the temperature will boost the
speed (rate) of photosynthesis.
2) Increasing the intensity will boost the
speed (rate) of photosynthesis.

92. Changing the Limiting Factor
2.19 understand how varying carbon dioxide concentration, light intensity and temperature affect the rate of photosynthesis
Adding more of the rate-limiting factor increases the rate
further…….............until another factor becomes limiting.

93. What about Water?
2.19 understand how varying carbon dioxide concentration, light intensity and temperature affect the rate of photosynthesis
Water is not seen as a limiting factor.
Plants have enough water in their tissues for
photosynthesis.
If they do not have enough water the plant will wilt
and die anyway.
Very sad, but very true.

94. Leaf Structure
2.20 describe the structure of the leaf and explain how it is adapted for photosynthesis
You need to know the parts of the leaf and their
adaptations.
DO NOT
DRAW
THIS
DIAGRAM

95. SIMPLE CROSS SECTIONAL LEAF DIAGRAM
2.20 describe the structure of the leaf and explain how it is adapted for photosynthesis

96. More Complicated Cross Section
2.20 describe the structure of the leaf and explain how it is adapted for photosynthesis

97. In Real Life
2.20 describe the structure of the leaf and explain how it is adapted for photosynthesis

98. LABEL
2.20 describe the structure of the leaf and explain how it is adapted for photosynthesis

99. Adaptation
2.20 describe the structure of the leaf and explain how it is adapted for photosynthesis

100. Which Tissues Are Missing?
2.20 describe the structure of the leaf and explain how it is adapted for photosynthesis
Please add into your notes any tissue missing
and write in their functions:
1) Xylem
2) Phloem
3) Vascular Bundle
4) Spongy Mesophyll

101. Minerals for Nutrition
2.21 understand that plants require mineral ions for growth and that magnesium ions are needed for chlorophyll and nitrate ions are needed for
amino acids
In addition to water and CO2 plants also need specific
minerals;
• Nitrate – used to make amino acids for use in plant
proteins Magnesium – forms part of the chlorophyll
molecule
• Potassium - essential for cell membranes
• Phosphate - essential part of DNA and cell
membranes

102. Experiment we CAN NOT do!

103. EXPERIMENTS WE CAN DO
2.22 describe experiments to investigate photosynthesis, showing the evolution of oxygen from a water plant, the production of starch and the requirements of light, carbon dioxide and
chlorophyll

104. Using Pond Weed
2.22 describe experiments to investigate photosynthesis, showing the evolution of oxygen from a water plant, the production of starch and the
requirements of light, carbon dioxide and chlorophyll
You must know an experiment that shows how the rate of
photosynthesis is affected by rate-limiting factors.
Example: Use pond weed (Elodea) which produces bubbles of O2 as it
photosynthesizes.
1) The rate of bubble production is proportional to the rate of
photosynthesis.
2) When you add light or give it more CO2, the rate of bubble
production increases.
Watch out:
 Cut Elodea underwater or air bubbles will form in xylem
 Make sure the O2 is a result of light and not temperature
 The examiner may ask for a better way to measure O2 production

105. Set up for Photosynthesis Rate Vs Light intensity
2.22 describe experiments to investigate photosynthesis, showing the evolution of oxygen from a water plant, the production of starch and the requirements
of light, carbon dioxide and chlorophyll
Change:
Light
intensity
(distance of
lamp from
Elodea)
Measure:
Number of
bubbles per
minute

106. Setup for Photosynthsis Rate Vs CO2
Concentration
2.22 describe experiments to investigate photosynthesis, showing the evolution of oxygen from a water plant, the production of starch and the requirements
of light, carbon dioxide and chlorophyll
Change: Concentration
of Sodium Hydrogen
Carbonate Solution (CO2)
Measure: Number of
bubbles per minute

107. Testing Photosynthesis by Starch
2.22 describe experiments to investigate photosynthesis, showing the evolution of oxygen from a water plant, the production of starch and the requirements
of light, carbon dioxide and chlorophyll
You need to know an experiment that proves that
light and CO2 are essential for the production of
starch.
A good example is the Geranium plant. It’s leaves
normally turn blue-black in the presence of iodine
solution showing starch is present
(you have to boil it in ethanol first to remove the
chlorophyll to show the colour).

108. Testing Photosynthesis by Starch
2.22 describe experiments to investigate photosynthesis, showing the evolution of oxygen from a water plant, the production of starch and the requirements
of light, carbon dioxide and chlorophyll
Negative Test:
Reddish / Brown
Positive Test:
Blue / Black
Safety: Why is it dangerous to
boil ethanol directly with a
Bunsen Burner instead of using
a water bath?

109. Destarching
2.22 describe experiments to investigate photosynthesis, showing the evolution of oxygen from a water plant, the production of starch and the requirements of light, carbon
dioxide and chlorophyll
You will want to destarch a leaf for this experiment.
To remove the starch (destarch)
1) put the poor plant in a dark room for 24 hours.
2) No light means no photosynthesis, no
photosynthesis means no glucose produced, no
glucose produced means no starch stored in the leaf.
Sadly the leaf still needs to respire so it will break all
the previously stored starch back into glucose to use
in respiration. No more starch, poor leaf…

110. Destarching
2.22 describe experiments to investigate photosynthesis, showing the evolution of oxygen from a water plant, the production of starch and the requirements of light, carbon
dioxide and chlorophyll
However, if one leaf is
put in aluminium foil
and another is kept
with lime water both
do not turn blue-black.
Both CO2 and light are essential for starch production
and, therefore, essential for photosynthesis.

111. Nutrition in Humans
Syllabus points 2.23 – 2.32

112. Balanced Diet
2.23 understand that a balanced diet should include appropriate proportions of carbohydrate, protein, lipid, vitamins, minerals, water and dietary fibre(TA)
A diet that contains
adequate amounts of all the
necessary nutrients required
for healthy growth and
activity.
A balanced diet is one that
contains all the ingredients
needed for our body to
healthily continue its day to
day functions in the most
efficient way.

113. Balanced Diet
2.23 understand that a balanced diet should include appropriate proportions of carbohydrate, protein, lipid, vitamins, minerals, water and dietary fibre(TA)

114. Balanced Diet
2.23 understand that a balanced diet should include appropriate proportions of carbohydrate, protein, lipid, vitamins, minerals, water and dietary fibre(TA)
72% of our body is WATER.
We contain so much water because water:
-Distributes essential nutrients to cells,
such as minerals, vitamins and glucose as
part of the plasma in our blood
-Is an integral part of urine and faeces,
which removes waste from our body
-Is needed for sweat (sweat is essential in
controlling our internal body
temperature)

115. What do you have to eat
2.24 identify sources and describe functions of carbohydrate, protein, lipid (fats and oils), vitamins A, C and D, and the mineral ions calcium and iron, water and dietary fibre as components of
the diet
Component Function Example of sources
Carbohydrate Short-term chemical energy Bread, potatoes
Lipids (fats and oils) Long-term chemical energy Bacon, beef
Protein Growth & Repair Fish, egg
Vitamin A Eyesight Carrots, fish liver oil
Vitamin C Healthy skin + gums Oranges
Vitamin D Absorb Ca (calcium) Sunlight
Mineral ions – Fe (iron) Making haemoglobin in RBC Spinach, animal liver
Mineral ions – Ca (calcium) Strong bones and teeth milk
Dietary fiber Peristalsis Vegetables, cereal
Water Transport system
To sweat
All chemical reactions occur in
solution inside cells
Fruits like watermelon

116. Not all bodies are Energy (J) Equal
2.25 understand that energy requirements vary with activity levels, age and pregnancy (TA)
Person Energy needed per day (kJ)
Newborn baby 2000
Age 2 5000
Age 6 7500
Gril age 12-14 9000
Boy age 12-14 11000
Girl age 15-17 9000
Boy age 15-17 12000
Female office worker 9500
Male office worker 10500
Heavy manual worker 15000
Pregnant woman 10000
Breast-feeding woman 11300

117. Not all bodies are Energy (J) Equal
2.25 understand that energy requirements vary with activity levels, age and pregnancy (TA)
The two groups that provide energy (through respiration) are lipids and
carbohydrates.
Per mass lipids have about 10x more energy in them than
carbohydrates.
The energy in food is measured in Calories (equivalent to 4.2 kJ).
If Males need to consume 2500 Calories a day and Females need to consume 2000
Calories a day how many kJ do they need to consume in a day?
If:
Fat: 1 gram = 9 calories
Carbohydrates: 1 gram = 4 calories
How many grams of each do you need to supply your energy for the day?

118. Not all bodies are Energy (J) Equal
2.25 understand that energy requirements vary with activity levels, age and pregnancy (TA)
Energy requirements vary according to several factors:
• Age: growing people require more energy than others.
• Gender: on average, males require more energy than
females.
• Pregnancy: pregnant women require more energy to
nourish themselves and the baby.
• Activity levels: more active people require more energy
as they use up more energy throughout the day.

119. Name that structure
2.26 describe the structures of the human alimentary canal and describe the functions of the mouth, oesophagus, stomach, small intestine, large intestine and pancreas
game

120. Describe the function
2.26 describe the structures of the human alimentary canal and describe the functions of the mouth, oesophagus, stomach, small intestine, large intestine and pancreas
• Functions
Mouth • Physical digestion by teeth
• Salivary glands produce saliva 
moistens food  making it easier to be
swallowed
• Chemical digestion by amylase breaks
down starch into maltose
Oesophagus • Food is moved by peristalsis
Stomach • Produces HCl & protease (pepsin)
enzymes
Small intestine • Produces carbohydrase (maltase),
protease (trypsin) & lipase enzymes
• Absorbs digested food
Large intestine • Absorbs water
Pancreas • Produces carbohydrase (maltase),
protease (trypsin) & lipase enzymes

121. Flow Chart the Process
2.27 understand the processes of ingestion, digestion, absorption, assimilation and egestion
Ingestion
• Taking food into
the body
Digestion
• The breakdown of large
insoluble molecules into
small soluble molecules
so they can be absorbed
into the blood
Absorption
• The process of
absorbing nutrients
into the body after
digestion
Assimilation
• Using food
molecules to build
new molecules
Egestion
• Getting rid of
undigested/unwan
ted food

122. Flow Chart the Process
2.27 understand the processes of ingestion, digestion, absorption, assimilation and egestion
Digestion can be mechanical or chemical
Mechanical Digestion: digestion by physically breaking food into smaller pieces (i.e. not using
enzymes). Carried out by;
• mouth and teeth chewing food
• stomach churning food
Chemical Digestion: digestion using enzymes

123. Peristalsis
2.28 explain how and why food is moved through the gut by peristalsis
Food is moved the digestive
system by a process known as
peristalsis.
This is the contractions of two
sets of muscles in the walls of
the gut.
1) One set runs along the gut
2) The other set circles it.
Their wave-like contractions
create a squeezing action,
moving down the gut. ani

124. Digestive Enzymes
2.29 understand the role of digestive enzymes, to include the digestion of starch to glucose by amylase and maltase, the digestion of proteins to amino acids by proteases and the digestion of lipids to fatty acids and
glycerol by lipases
Enzymes and digestion
The enzymes involved in respiration, photosynthesis and protein synthesis work inside
cells.
Other enzymes are produced by specialised cells and released from them these are
digestive enzymes.
They pass out into the gut, where they catalyse the breakdown of food molecules.
Different enzymes
(Different enzymes catalyse different digestion reactions)
Amylase Starch → sugars
Amylase catalyses the breakdown of starch into sugars in the mouth and small intestine
Protease Proteins → amino acids
Proteases catalyse the breakdown of proteins into amino acids in the stomach and small intestine
Lipase Lipids → fatty acids + glycerol
Lipases catalyse the breakdown of fats and oils into fatty acids and glycerol in the small intestine

125. Bile is not so Vile
2.30 understand that bile is produced by the liver and stored in the gall bladder, and understand the role of bile in neutralising stomach acid and emulsifying lipids
After the stomach, food travels to the small intestine. The enzymes in
the small intestine work best in alkaline conditions, but the food is
acidic after being in the stomach.
• Bile is alkaline substance
• Bile is produced by the
liver
• Bile is stored in the gall
bladder.
• Bile is secreted into the
small intestine, where it
emulsifies fats
This is important, because it
provides a larger surface
area in which the lipases can
work.

126. Silli Villi
2.31 describe the structure of a villus and explain how this helps absorption of the products of digestion in the small intestine
The Villus is the location of Absorption of small soluble
nutrients into to blood.

128. How much energy is in that crisp?
2.32 describe an experiment to investigate the energy content in a food sample.(TA)
You need to know an experiment that can show how much energy there is in food.
Burn a sample of food and use it to heat a fixed volume of water. Record the change in
temperature of the water and use the equation below to find out the energy the food gave to the
water;
Energy = change in temp. x volume of water x 4.2J/g/°C
Problem is that not all the food will burn.
To control this, you measure the start and end mass of the food and calculate the mass that
actually burned.
To standardize this, you can divide your calculated energy value by the change in mass to give
you the change in mass per gram of food
(which will allow you to compare values fairly between different food samples)

129. How much energy is in that peanut?
2.32 describe an experiment to investigate the energy content in a food sample.(TA)
There are problems with using this system:
Heat from food item does not heat water
Not all the food burns
Water looses heat to environment
So what is the solution?

130. Respiration releases ENERGY
2.33 understand that the process of respiration releases energy in living organisms

131. Aerobic and Anerobic
2.34 describe the differences between aerobic and anaerobic respiration

132. Word and Chemical Equation
2.35 write the word equation and the balanced chemical symbol equation for aerobic respiration in living organisms

133. Anaerobic Repiration Word Equation
2.36 write the word equation for anaerobic respiration in plants and in animals

134. Experiment for Respiration
2.37 describe experiments to investigate the evolution of carbon dioxide and heat from respiring seeds or other suitable living organisms.

135. Gas Exchange
2.38 understand the role of diffusion in gas exchange

136. GAS EXCHANGE IN PLANTS
2.39 understand gas exchange (of carbon dioxide and oxygen) in relation to respiration and photosynthesis
CO2 and O2 diffuse in and out of leaves through stomata.
CO2 is used in photosynthesis and produced
by respiration, whereas O2 is used in
respiration and produced in photosynthesis!

137. Photosynthesis & Respiration
2.39 understand gas exchange (of carbon dioxide and oxygen) in relation to respiration and photosynthesis
Both processes run all the time. So the net amount of
glucose the plant produces (i.e. the amount it gets to
use for growth etc) is governed by the formula;
Net Glucose = Total production – Amount used in respiration
The Compensation Point is defined as;
0 = Total production – Amount used in respiration
Or
Photosynthesis = Respiration

138. Light Intensity & Gas Exchange
2.40 understand that respiration continues during the day and night, but that the net exchange of carbon dioxide and oxygen
depends on the intensity of light (TA)
The amount of glucose the plant uses in respiration in
nearly constant.
However, glucose production by photosynthesis is not.
It is dependent on the rate-limiting factors (i.e. light
intensity, CO2 level, water availability, temperature etc).
At night photosynthesis is virtually zero.
(Net Carbon Dioxide production)
In the day the photosynthesis is large.
(Net Oxygen production)

139. Light
Intensity &
Gas
Exchange
2.40 understand that respiration
continues during the day and night,
but that the net exchange of carbon
dioxide and oxygen depends on the
intensity of light (TA)

140. Leaf Structure and Photosynthesis
2.41 explain how the structure of the leaf is adapted for gas exchange

141. Stomata and Gas Exchange
2.42 describe the role of stomata in gas exchange
In sunlight the guard cell becomes turgid
Turgid guard cells open the stoma
Increases gas exchange
Low light causes guard cells to become flaccid
Flaccid guard cells close the stoma
Decreases water loss

142. Stomata and Gas Exchange
2.42 describe the role of stomata in gas exchange
Exp
1
Exp
2

143. Stomata and Gas Exchange
2.42 describe the role of stomata in gas exchange
Potometer
1) You must cut the shoots under water and you must
assemble the potometer under water. If air gets into the
xylem vessels of the plant, it can form air locks which will
prevent the plant taking up water and so prevent steady
transpiration.
1) Check all seals are airtight – coat seals with Vaseline jelly
3) The potometers should be left for the leaves to dry.
Alternatively dry the leaves gently with a paper towel. The
potometer will not work properly until any excess water
on the leaves has evaporated or been removed.
2) Adding food colouring to the water makes it easier to see
the air bubble in the capillary tube.

144. Stomata and Gas Exchange
2.42 describe the role of stomata in gas exchange

145. Experiment to Know
2.43 describe experiments to investigate the effect of light on net gas exchange from a leaf, using hydrogen-carbonate indicator (TA)
An experiment which will show the effect of light intensity on the
rate of gas exchange.
- Seal two leaves (still attached to the plant) in separate plastic
bags with some bicarbonate indicator solution.
- One of the bags is black and the other is translucent.
- The leaf in the black bag produces CO2 via respiration and the
colour of the bicarbonate indicator changes quickly to yellow.
- The leaf in the translucent bag produces O2 via photosynthesis
and the bicarbonate indicator solution changes to red slowly.
Bicarbonate Indicator colours:
Red in the absence of CO2
Yellow in the presence of CO2

146. Gas Exchange in Humans
Syllabus points 2.44 – 2.48

147. Gas Exchange in Humans
Syllabus points 2.44 – 2.48

148. Gas Exchange in Humans
Syllabus points 2.44 – 2.48

149. Gas Exchange in Humans
Syllabus points 2.44 – 2.48

150. Transport
syllabus points 2.49 – 2.50

151. Transport
syllabus points 2.49 – 2.50

152. Plant Transport (2.51 – 2.56)
2.51 describe the role of phloem in transporting sucrose and amino acids between the leaves and other parts of the plant

153. Plant Transport (2.51 – 2.56)
2.51 describe the role of phloem in transporting sucrose and amino acids between the leaves and other parts of the plant

154. Plant Transport (2.51 – 2.56)
2.51 describe the role of phloem in transporting sucrose and amino acids between the leaves and other parts of the plant

155. Plant Transport (2.51 – 2.56)
2.51 describe the role of phloem in transporting sucrose and amino acids between the leaves and other parts of the plant

156. Plant Transport (2.51 – 2.56)
2.51 describe the role of phloem in transporting sucrose and amino acids between the leaves and other parts of the plant

157. Transport in Humans (2.57 – 2.66)

158. Transport in Humans (2.57 – 2.66)

159. Transport in Humans (2.57 – 2.66)

160. Transport in Humans (2.57 – 2.66)

161. Transport in Humans (2.57 – 2.66)

162. Transport in Humans (2.57 – 2.66)

163. Transport in Humans (2.57 – 2.66)

164. Transport in Humans (2.57 – 2.66)

165. Transport in Humans (2.57 – 2.66)

166. Excretion in Plants
2.67 understand the origin of carbon dioxide and oxygen as waste products of metabolism and their loss from the stomata of a leaf

167. Excretion in Humans (2.68 – 2.76)
2.68 recall that the lungs, kidneys and skin are organs of excretion
Humans have 3 main excretory organs
1) Lungs – excrete CO2 and H2O
2) Skin – excretes H2O
3) Kidneys – excrete H2O, urea, excess
minerals and other wastes. Parts
game

168. UREA
2.68 recall that the lungs, kidneys and skin are organs of excretion
What’s urea? (not technically on syllabus)
• All organisms produce ammonia as they metabolize
nutrients (protein digestion/amino acids)
• Ammonia is a nitrogenous waste that is toxic and must
be removed from the body
Solution: the liver turns the ammonia into urea, which is
harmless.
Therefore urea is a product of the metabolism of amino
acids.

169. UREA
2.68 recall that the lungs, kidneys and skin are organs of excretion
Many land animals and some bony fish (amphibians,
mammals) dilute the toxic ammonia with water.
This substance is called Urea & is filtered out by the
kidneys.
- The problem is they do lose water in the process
- Requires Energy

170. Excretion & Osmoregulation
2.69 understand how the kidney carries out its roles of excretion and osmoregulation
The Kidney:
The functional unit of the kidney is the nephron. There are
millions of nephrons in a single kidney.
Nephrons have 2 jobs;
Excretion - filtering the blood
and reclaiming the “good bits”
& removing waste
Osmoregulation - balancing the
water level of the body (water
homeostasis)

171. Excretion System
2.70 describe the structure of the urinary system, including the kidneys, ureters, bladder and urethra

172. Excretion System
2.70 describe the structure of the urinary system, including the kidneys, ureters, bladder and urethra

173. Kidney
Nephron and the Kidney
2.71 describe the structure of a nephron, to include Bowmancs capsule and glomerulus, convoluted tubules, loop of Henlé and collecting duct

174. Nephron and capilliaries
2.71 describe the structure of a nephron, to include Bowmancs capsule and glomerulus, convoluted tubules, loop of Henlé and collecting duct

175. How the Nephron works
2.71 describe the structure of a nephron, to include Bowmancs capsule and glomerulus, convoluted tubules, loop of Henlé and collecting duct
2.74 understand that selective reabsorption of glucose occurs at the proximal convoluted tubule
How the nephron works:
1) Dirty blood enters the kidney via the afferent artery
2) The artery splits up into a ball of capillaries, called the glomerulus
3) The blood is under high pressure, so all small substances are forced
out of the holes in the capillary walls. Only large proteins and cells stay
behind.
4) The small substances (glucose, minerals, urea, water etc) move into
the bowman’s capsule, which wraps around the glomerulus
5) The capsule leads into the PCT, which re-absorbs all glucose via active
transport (i.e. it selectively removes the glucose from the nephron and
returns it to the blood)

176. How the Nephron works
2.71 describe the structure of a nephron, to include Bowmancs capsule and glomerulus, convoluted tubules, loop of Henlé and collecting duct
6) The PCT leads to the Loop of Henlé, which re-absorbs the water by osmosis
7) The Loop leads to the DCT, which re-absorbs all minerals, amino acids and other
“useful” substances by active transport
8) The remaining fluid (containing excess water, excess minerals and urea) passes into
the collecting duct
9) The collecting ducts from other nephrons join and form the ureter, which leads to
the bladder
10) The fluid is now called urine and is stored in the bladder for excretion
11) The bladder takes the urine to the outside world via the urethra
This is the first role of the nephron (it’s role in excretion).
Remember, the nephron has a second role in osmoregulation.

177. Excretion in Humans (2.68 – 2.76)
2.71 describe the structure of a nephron, to include Bowmancs capsule and glomerulus, convoluted tubules, loop of Henlé and collecting duct
Kidney

178. Excretion in Humans (2.68 – 2.76)
2.72 describe ultrafiltration in the Bowmancs capsule and the composition of the glomerular filtrate
The glomerulus
filters blood and
produces glomerular
filtrate.
This filtrate contains:
water, glucose, salts
and urea (amino
acids).
(Large molecules such as
protein are too large to
fit through the blood
capillary walls.)

179. Excretion in Humans (2.68 – 2.76)
2.73 understand that water is reabsorbed into the blood from the collecting duct
Teach
Blood water levels are sensed by the hypothalamus in the brain.
When water levels are too low, the hypothalamus tells the pituitary
gland (also in the brain) to release the hormone Anti-Diuretic Hormone
(ADH)

180. Excretion in Humans (2.68 – 2.76)
2.73 understand that water is reabsorbed into the blood from the collecting duct
2.75 describe the role of ADH in regulating the water content of the blood
When blood water levels are too low;
1) Hypothalamus detects
2) Pituitary gland releases ADH into bloodstream
3) ADH travels all over the body
4) Only the cells in the collecting duct of the nephrons of the kidney have
receptors for ADH, so only they respond to the hormone
5) The collecting duct becomes more permeable
6) Water is draw out of the collecting duct back into the blood
7) Water levels return to normal
BBC

181. Review of Urine
2.76 understand that urine contains water, urea and salts.
The waste, consisting of:
• excess water
• excess salts
• urea
is urine.
This process can be summarized in three important steps:
Revision
1) Ultra-Filtration - where lots of water, ions, urea and sugar are squeezed from the
blood into the tubules.
2) Selective reabsorption – the useful substances (ions and sugars) are reabsorbed
back into the blood from the tubules. The amount of water in the blood is regulated
here to maintain it at a constant rate. This is known as ‘osmoregulation’.
3) Excretion of waste - urea and excess water and ions travel to the bladder as urine,
to be released from the body.

182. Coordination and Response
Homeostasis: the maintenance of a constant
internal environment

183. The S in MRS GREN
2.77 understand that organisms are able to respond to changes in their environment
M Movement All living things move, even plants
R Respiration Getting energy from food
S Sensitivity Detecting changes in the surroundings
G Growth All living things grow
R Reproduction Making more living things of the same type
E Excretion Getting rid of waste
N Nutrition Taking in and using food
SENSITIVITY
A stimulus is a change in the environment of an organism.
Animals respond to a stimulus in order to keep themselves in favourable conditions.
Examples of this include:
• moving to somewhere warmer if they are too cold
• moving towards food if they are hungry
• moving away from danger to protect themselves
Animals that do not respond to a stimulus do not survive for long.

184. Homeostasis
2.78 understand that homeostasis is the maintenance of a constant internal environment and that body water content and body
temperature are both examples of homeostasis
All organisms try and maintain a constant
internal environment. This is called
homeostasis.
Examples of homeostasis include:
1) The regulation of water levels.
2) The regulation of body temperature.

185. Stimulus > Receptor> Coordination >
Effector > Response
2.79 understand that a coordinated response requires a stimulus, a receptor and an effector
• Both systems respond to stimuli
(i.e. events that change the internal environment).
• Both systems have a:
1) Receptor, which detects the stimulus.
2) Effector, which carries out a response to correct the effect of
the stimulus.
The message from detector to effector is carried either via an
electrical nerve impulse or as a hormone, depending which
homeostatic system is being used.

186. STIMULI
2.79 understand that a coordinated response requires a stimulus, a receptor and an effector

187. Examples of Receptors and Effectors
2.79 understand that a coordinated response requires a stimulus, a receptor and an effector
Receptor
ORGAN RECEPTOR
skin Temperature Receptor
skin Pressure / Pain Receptor
Brain (hypothalamus) Water Concentration Receptor
Eye (retina) Light Receptors (Rods & Cones)
Effectors
ORGAN EFFECTOR
Heart Muscle cell
Skin Sweat gland
Kidney Collecting duct walls

188. STIMULI
2.79 understand that a coordinated response requires a stimulus, a receptor and an effector
Receptors detect Stimuli. Some examples are:
a) Light Eye (retina)
b) Sound Ear (hearing)
c) Movement (K.E) Ear (balance) / Skin
d) Chemical Nose / Tongue
e) Heat Skin

189. Response in Plants
2.80 understand that plants respond to stimuli
Plants also respond to stimuli. As plants don’t have
nerves their responses are limited to hormones only.
Plants respond to the following stimuli:
• Gravity: Roots grow towards gravitational pull and
stems grow away. This is Geotropism.
• Water: Roots grow towards water. This is
Hydrotropism.
• Light: Shoots grow towards light. This is Phototropism.

190. GEOTROPISM
2.81 describe the geotropic responses of roots and stems
Shoot tips and Root tips respond to GRAVITY.
• Shoot tips grow away from gravity (Negative
Geotropism)
• Root tips grow in the direction of gravity (Positive
Geotropism)

191. WHY
You only need to know that plants respond to a
chemical hormone called
AUXIN
BUT if you want more………
2.81 describe the geotropic responses of roots and stems

192. 2.81 describe the geotropic responses of roots and stems

193. 2.81 describe the geotropic responses of roots and stems
You do need to know some fun
experiments with plants

194. 2.81 describe the geotropic responses of roots and stems
What happens when you grow a plant
in space?

195. Positive Phototropism
2.82 describe positive phototropism of stems
Positive Phototropism is controlled by hormones
released by the growing tip of the shoot.
(Only the tip makes the hormone)
If you remove the tip, the shoot stops growing.
The hormone made by the tip is called
Auxin
(which part of the plant would be controlled by
Negative Phototropism?)

196. 2.82 describe positive phototropism of stems

197. MORE
EXPERIMENTS
2.82 describe positive phototropism of stems

198. 2.82 describe positive phototropism of stems
What if you grow a plant in the dark?

199. Response Systems
2.83 describe how responses can be controlled by nervous or by hormonal communication and understand the differences
between the two systems
Humans have two systems which carry out
detection and response:
• Nervous System – Chemical electrical system
using Neurons
Example: Iris dilation, movement, ventilation
• Endocrine System –Chemical system using
proteins called hormones in the blood.
Example: Osmoregulation, Fight or Flight,
Menstruation.

200. Differences
2.83 describe how responses can be controlled by nervous or by hormonal communication and understand the differences
between the two systems
Nervous System Endocrine System
Works by nerve impulses
(has chemicals in synapses though)
Works by hormones transmitted
in blood stream
Travel fast and usually have
‘instant’ effect
Travel slowly and may take longer
to ask
Response is short lived Response is usually longer lasting
Impulse act on individual cells
(localised effect)
Widespread effects on different
organs (still only work on
cells/organs with correct
receptors)

201. Nervous System
2.84 understand that the central nervous system consists of the brain and spinal cord and is linked to sense organs by nerves
The Central Nervous System
(CNS) consists of
1) the brain
2) the spinal cord
There are also Peripheral
Nerves System (PNS)
1) Sensory Nerves/organs
(e.g. pain receptors in
skin, or photoreceptors
in the eye)
2) nerves that link brain
and sense organs
3) Motor Nerves

202. 2.85 understand that stimulation of receptors in the sense organs sends electrical impulses along nerves into and out of the central nervous
Stimulation of the sense organs results in an electrical signal
(a nerve impulse) being sent along the nerve to the brain.
Nerve impulses are very quick (~120m/s), allowing rapid
responses to the stimulus.
nerve impulse
Nerve Impulse
synaptic cleft
receptor
system, resulting in rapid responses

203. DIFFUSION AGAIN??
2.85 understand that stimulation of receptors in the sense organs sends electrical impulses along nerves into and out of the central nervous system, resulting in rapid responses
(You do not have to know the terms just the ideas)
1) An electrical impulse travels along a nerve
ending.
2) This triggers the nerve-ending of a neuron
to release chemical messengers called
neurotransmitters.
3) These chemicals diffuse across the
synapse (the gap) and bind with receptor
molecules on the membrane of the next
neuron.
4) The receptor molecules on the second
neuron bind only to the specific chemicals
released from the first neuron. This stimulates
the second neuron to transmit the electrical
impulse.

204. REFLEXS
2.86 describe the structure and functioning of a simple reflex arc illustrated by the withdrawal of a finger from a hot object
Some sense organs are not connected directly to
the brain.
This is a defence mechanism allowing almost
instant responses to threatening or dangerous
stimuli (e.g. pain/hot object).
These instant responses are controlled by nerves
in the spine, rather than the brain and are called
reflexes

205. REFLEX ARC
2.86 describe the structure and functioning of a simple reflex arc illustrated by the withdrawal of a finger from a hot object
Relay Neuron

206. STEP BY STEP REFLEX ARC
2.86 describe the structure and functioning of a simple reflex arc illustrated by the withdrawal of a finger from a hot object
1) A stimulus is detected by a receptor
2) The receptor initiates a nerve impulse in the sensory
nerve
3) The sensory nerve (which runs from the receptor to the
spine) passes the message/impulse onto an
interneuron/Relay Neuron in the spine
4) The interneuron/relay neuron passes the message on the
a motor nerve
5) The motor nerve (which runs from the spine to a muscle
in the same limb as the receptor) passes the message
onto the effector muscle
6) The effector muscle carries out the response (muscle
contraction).

207. Reflex Arc Timing
2.86 describe the structure and functioning of a simple reflex arc illustrated by the withdrawal of a finger from a hot object
The entire process (stimulus to response)
happens in less than a second and does not
involve the brain.
The purpose of the interneuron is also to inform
the brain of what has happened.
Reflex Summary
1) Immediate response to stimulus
2) Automatic reactions
3) Limits damage to organism

208. THE EYE

209. EyE WebSites
2.87 describe the structure and function of the eye as a receptor
a) Label the eye
http://www.kscience.co.uk/animations/eye_drag.htm
b) Function of the eye
http://www.kscience.co.uk/animations/eye_function_drag.htm
c) Label the eye
http://www.freezeray.com/flashFiles/eye.htm
d) Light and the eye
http://www.kscience.co.uk/animations/eye.htm
e) Fun with your blind spot
http://www.med.yale.edu/neurobio/mccormick/fill_in_seminar/figure1.htm

210. EYE DIAGRAM
2.87 describe the structure and function of the eye as a receptor
Conjunctiva

211. Define these Terms
2.87 describe the structure and function of the eye as a receptor
• Ciliary Body (muscle)
• Iris
• Pupil
• Cornea
• Lens
• Suspensory Ligament
• Sclera
• Choroid
• Retina
• Fovea
• Optic Disk (blind spot)
• Optic Nerve
• Conjunctiva
Contracts to Relaxes to change shape of lens
Coloured muscular part of eye that controls pupils size
Opening in the iris that lets light through to the retina
Transparent front part of the eye that refracts light
Transparent part of the eye that bends light (refracts)
Ligament that controls the shape of the lens
Dense white covering of the eye
Vascular membrane of the eyeball between the sclera and the retina
& stops light reflecting around in the eye
Light sensitive membrane that converts light to electrical signals to the brain
Part of the retina with a high density of cones for very sharp vision
Area of retina that is insensitive to light
Where electrical impulses from retina travel to brain
helps lubricate the eye by producing mucus and tears

212. RODS & CONES
2.87 describe the structure and function of the eye as a receptor
Light is detected by photoreceptors in the eye.
These receptors form the retina (the inner lining of
the eye).
There are two types of photoreceptor
Rods, which see only in &
&
Cones, which see in either red, blue or green
(3 types of cones)
Hint: Cone and Colour both start with ‘C’

213. Automatic Reflexs
2.88 understand the function of the eye in focusing near and distant objects, and in responding to changes in light intensity (TA)
There are two types of reflex you need to know
about in the eye
1) Responding to different light levels
2) Focusing the eye

214. Responding to Light Levels
(Antagonistic Muscle Pairs at Work)
2.88 understand the function of the eye in focusing near and distant objects, and in responding to changes in light intensity (TA)
Condition (Stimulus) Bright light Dim light
Receptors More photoreceptors stimulated Less photoreceptors stimulated
Impulses More impulses sent to the brain via
optic nerve
Fewer impulses sent to the brain
via optic nerve
Effectors Radial muscles of the iris relax Radial muscles of the iris contract
Circular muscles of the iris contract Circular muscles of the iris relax
Gross Effect Pupil constricts (becomes smaller) Pupil dilates (becomes larger)
Less light enters the eye More light enters the eye

215. FOCUSING THE EYE
2.88 understand the function of the eye in focusing near and distant objects, and in responding to changes in light intensity (TA)
Cilary Muscle & Suspensory Ligaments
Ciliary fibers are also
know as
Suspensory ligaments
Cilary Muscle Contracted
& Suspensory Ligament
Relaxed
Cilary Muscle Relaxed
& Suspensory Ligament
Contracted

216. 2.88 understand the function of the eye in focusing near and distant objects, and in responding to changes in light intensity (TA)
Distant Focus
Cilary Muscle relax
ACCOMODATION
(Focusing)
Suspensory Ligaments contract
Lens is pulled
Lens is thin
Light rays bent slightly
Light rays focus on retina
Close Focus
Cilary Muscle contract
Suspensory Ligaments relax
Lens is not pulled
Lens is fat
Light rays are bent strongly
Light rays focus on retina

217. Controlling Skin Temperature
2.89 describe the role of the skin in temperature regulation, with reference to sweating, vasoconstriction and
vasodilation (TA)
Too HOT Too COLD
When you are HOT the following
happens (controlled by reflexes)
When you are cold the following
happens (controlled by reflexes)
1) Hairs on skin lie flat (less
insulating air trapped)
1) Hairs on skin stand up (more
insulating air trapped)
2) Sweating starts 2) Sweating stops
3) Blood is diverted close to the
surface of the skin (more heat
radiation)
3) Shivering starts, so muscles
respire more, producing more
heat.
4) Blood is diverted away from the
surface of the skin (less heat
radiation)

218. 2.89 describe the role of the skin in temperature regulation, with reference to sweating, vasoconstriction and vasodilation (TA)

219. Blood is diverted
2.89 describe the role of the skin in temperature regulation, with reference to sweating, vasoconstriction and vasodilation (TA)
Arterioles in the skin can open and close in
response to nerve messages.
Vasoconstriction – arteriole closes
Vasodilation – arteriole opens

220. Hormones involved in Coordination
2.90 understand the sources, roles and effects of the following hormones: ADH, adrenaline, insulin, testosterone,
progesterone and oestrogen.
Hormone Source Effect
ADH Pituitary Regulated blood osmoregulation
Adrenaline Adrenal glands Increases heart rate and breathing rate
during exercise (more O2 for respiration)
Insulin Pancreas
Decreases blood glucose level after a meal.
Glucose converted to Glycogen and stored in
liver.
Testosterone Testes
Triggers puberty in boys (secondary sexual
characteristics)
Progesterone Ovaries Maintains uterus lining and (indirectly)
causes menstruation
Oestrogen Ovaries Triggers puberty in girls.
Stimulates growth of uterus lining each
month and (indirectly) causes ovulation

221. REPRODUCTION
3.1 understand the differences between sexual and asexual reproduction
There are two types of reproduction;
• Sexual: reproduction in which two gametes (sex
cells) fuse to create a new offspring that is
genetically different to the parents. Two parents
are involved.
• Asexual: reproduction without fusion of gametes. It
involves one parent only and produces offspring
that are genetically identical to the parent (clones).

222. Fertilization
3.2 understand that fertilisation involves the fusion of a male and female gamete to produce a zygote that
undergoes cell division and develops into an embryo
Definitions
• Fertilization:
• Zygote:
• Embryo:
A male and a female gamete fuse
to form a zygote
a cell that is the result of
fertilization. It will divide by mitosis
to form an embryo
An organism in its early stages of
development, especially before it
has reached a distinctively
recognizable form.

223. Reproduction in Plants
(3.3 - 3.7)

224. Reproduction in Plants
(3.3 - 3.7)

225. Reproduction in Plants
(3.3 - 3.7)

226. Reproduction in Plants
(3.3 - 3.7)

227. Structure and Function of Reproductive systems
3.8 describe the structure and explain the function of the male and female reproductive systems

228. Structure and Function of Reproductive systems
3.8 describe the structure and explain the function of the male and female reproductive systems

229. Structure and Function of Reproductive systems
3.8 describe the structure and explain the function of the male and female reproductive systems
DRAW IN YOUR OWN DIAGRAM
LABLE

230. MENSTRUAL CYCLE
3.9 understand the roles of oestrogen and progesterone in the menstrual cycle
The menstrual cycle in women is a recurring process, taking around 28 days.
During the process, the lining of the uterus - womb - is prepared for pregnancy.
If pregnancy does not happen, the lining is then shed at menstruation.
Several hormones control this cycle.
Oestrogen
The hormone oestrogen is secreted by the ovaries.
Oestrogen makes two things happen:
it stops more ovum being matured
it causes the thinkening of the uterus lining
Progesterone
Progesterone is a hormone secreted by ovaries.
It maintains the lining of the uterus during the middle part of the menstrual cycle and during
pregnancy.

231. MENSTRUAL CYCLE
3.9 understand the roles of oestrogen and progesterone in the menstrual cycle

232. MENSTRUAL CYCLE
3.9 understand the roles of oestrogen and progesterone in the menstrual cycle

233. PLACENTA
3.10 describe the role of the placenta in the nutrition of the developing embryo (TA)
Diffuse from
foetus to mother:
1) CO2
2) water,
3) Urea
Diffuse from
mother to foetus:
1) O2
2) glucose,
3) amino acids,
4) minerals

234. PLACENTA
3.10 describe the role of the placenta in the nutrition of the developing embryo (TA)
The placenta is
adapted for diffusion
in much the same
way as other
exchange organs:
1. Huge surface area (it
has lots of villi-like
projections)
2. Only a few cells thick
3. Blood supplies keep
the concentration
gradients high
4. Counter-current
system

235. AMNIOTIC FLUID
3.11 understand how the developing embryo is protected by amniotic fluid (TA)

236. SECONDARY SEXUAL CHARACTERISTICS
3.12 understand the roles of oestrogen and testosterone in the development of secondary sexual characteristics.

237. INHERITANCE
(Syllabus points 3.13 – 3.33)

238. REPRODUCTION (review)
3.1 understand the differences between sexual and asexual reproduction
There are two types of reproduction;
• Sexual: reproduction in which two gametes
(sex cells) fuse to create a new offspring that
is genetically different to the parents. Two
parents are involved.
• Asexual: reproduction without fusion of
gametes. It involves one parent only and
produces offspring that are genetically
identical to the parent (clones).

239. Fertilization (review)
3.2 understand that fertilisation involves the fusion of a male and female gamete to produce a zygote that
undergoes cell division and develops into an embryo
Definitions
• Fertilization:
• Zygote:
• Embryo:
A male and a female gamete fuse
to form a zygote
a cell that is the result of
fertilization. It will divide by mitosis
to form an embryo
An organism in its early stages of
development, especially before it
has reached a distinctively
recognizable form.

240. Fertilization, Zygote, Embryo(Review)
3.2 understand that fertilisation involves the fusion of a male and female gamete to produce a zygote that undergoes cell division and develops
into an embryo

241. Genes are on Chromosomes
3.13 understand that the nucleus of a cell contains chromosomes on which genes are located
The nucleus of every cell
contains DNA.
The DNA is organized in
genes and the genes are
located on
Chromosomes.
The best way to think
about it is like a library…. video press

242. 3.13 understand that the nucleus of a cell contains chromosomes on which genes are located
LIBRARY
Books
Chapters
Words
Letters
Nucleus
Chromosome
(23 pairs)
Gene
(makes one protein)
Group of 3 letters
DNA letters
(A, C, T, G)

243. 3.13 understand that the nucleus of a cell contains chromosomes on which genes are located

244. Genes Make a SPECIFIC Protein
3.14 understand that a gene is a section of a molecule of DNA and that a gene codes for a specific protein
1) Genes are written in DNA code.
2) The code can be translated into amino acids.
3) Amino Acids are linked together to make
proteins.
ONE Gene codes for ONE specific protein

245. Genes Make a SPECIFIC Protein
3.14 understand that a gene is a section of a molecule of DNA and that a gene codes for a specific protein
A three-base sequence codes for each amino acid.
base sequence amino acid

246. Genes Make a SPECIFIC Protein
3.14 understand that a gene is a section of a molecule of DNA and that a gene codes for a specific protein
Genes don’t actually make proteins – they just contain the instructions on how to make
them.
DNA stays in the nucleus but proteins are built in the cell’s cytoplasm.

247. 3.14 understand that a gene is a section of a molecule of DNA and that a gene codes for a specific protein
So Your Genes code for Your Proteins

248. WHAT IS DNA?
3.15 describe a DNA molecule as two strands coiled to form a double helix, the strands being linked by a series of paired bases: adenine (A) with
thymine (T), and cytosine (C) with guanine (G)
DNA is a very long molecule.
It is shaped like a twisted
ladder.
Two long strands make the
backbones and are connected
by rungs or links.

249. BASE PAIRS
3.15 describe a DNA molecule as two strands coiled to form a double helix, the strands being linked by a series of paired bases: adenine (A) with
thymine (T), and cytosine (C) with guanine (G)
The Strands are
connected by BASE
PAIRS
• Adenine (A)
• Thymine (T)
• Cytosine (C)
• Guanine (G)
The bases only match:
A-T
C-G

250. Genes come in Variations
3.16 understand that genes exist in alternative forms called alleles which give rise to differences in inherited characteristics
Sometimes more than one version of a gene occurs.
The different versions are called alleles
(i.e. we all have the gene for iris pigment (protein),
but there are different colours of iris pigment, same
gene but different alleles)

251. Alleles give rise to Variation
3.16 understand that genes exist in alternative forms called alleles which give rise to differences in inherited characteristics
over
view

252. Alleles give rise to Variation (2)
3.16 understand that genes exist in alternative forms called alleles which give rise to differences in inherited characteristics
Alleles give rise to a range of different inherited
characteristics in a population.
These can include in humans:
Eye Colour
Skin Colour
Hitch Hikers Thumb
Rolling of the tongue
Earlobe shape
Blood Type
Many many others………..

253. DEFINITIONS OF INHERITANCE TERMS
3.17 understand the meaning of the terms: dominant, recessive, homozygous, heterozygous, phenotype, genotype and co-dominance
Dominant:
A gene allele that ‘expresses’ over another allele in
homozygous and heterozyogus pairs. Shown in phenotype.
b
B
Recessive:
A gene allele that only ‘expresses’ when it is matched with
another recessive allele and never when matched with a
dominant allele. Homozygous Recessive. Shown in phenotype
b b

254. DEFINITIONS OF INHERITANCE TERMS
3.17 understand the meaning of the terms: dominant, recessive, homozygous, heterozygous, phenotype, genotype and co-dominance
Homozygous: having identical alleles at corresponding
chromosome Loci (Gene Location).
Heterozygous: having dissimilar alleles at
corresponding chromosomal Loci.
b B B B b b

255. DEFINITIONS OF INHERITANCE TERMS
3.17 understand the meaning of the terms: dominant, recessive, homozygous, heterozygous, phenotype, genotype and co-dominance

256. DEFINITIONS OF INHERITANCE TERMS
3.17 understand the meaning of the terms: dominant, recessive, homozygous, heterozygous, phenotype, genotype and co-dominance

257. DEFINITIONS OF INHERITANCE TERMS
3.17 understand the meaning of the terms: dominant, recessive, homozygous, heterozygous, phenotype, genotype and co-dominance
Phenotype: the set of observable
characteristics Geneotype
of an individual resulting
from the interaction of its genotype
with the environment
Genotype: The genetic makeup of a cell,
an organism, or an individual with
reference to a specific characteristic.
Environemnt
Phenotype

258. DEFINITIONS OF INHERITANCE TERMS
3.17 understand the meaning of the terms: dominant, recessive, homozygous, heterozygous, phenotype, genotype and co-dominance

259. 3.17 understand the meaning of the terms: dominant, recessive, homozygous, heterozygous, phenotype, genotype and co-dominance

260. DEFINITIONS OF INHERITANCE TERMS
3.17 understand the meaning of the terms: dominant, recessive, homozygous, heterozygous, phenotype, genotype and co-dominance
Codominance: A single gene has more than one dominant allele and both genes are
expressed.
The meaning of the prefix "co-" is "together". Cooperate = work together. Coexist =
exist together. Cohabitat = habitat together.
When writing alleles remember:
All alleles are CAPITAL letters
*I remember codominance in the form of an example like so:
red x ---> r d & h t s o t d

261. CODOMINANCE

262. Genetic Diagrams - Generations
3.18 describe patterns of monohybrid inheritance using a genetic diagram
Generations
There are the parents, then their offspring, and their offspring, etc. etc.
Each generation has a name.
The first plants or animals bred together are called the Parental generation, or P1 generation.
Their offspring are called the First Filial generation, or F1 generation.
Their offspring are called the Second Filial generation, or F2 generation.
And so on. And so on.

263. Genetic Diagrams – Punnett Squares
3.18 describe patterns of monohybrid inheritance using a genetic diagram
SOME SIMPLE EXAMPLES OF WHAT YOU CAN USE A
PUNNETT SQUARE FOR
SEED COLOUR FLOWER COLOUR GENDER
press

264. Genetic Diagrams – Punnett Squares
3.18 describe patterns of monohybrid inheritance using a genetic diagram
P1
P1
P1
Genotype of F2
press

265. Genetic Diagrams – Punnett Squares
3.18 describe patterns of monohybrid inheritance using a genetic diagram
How to diagram patterns in monohybrid inheritance:
1) Phenotype of Parents P1
2) Genotype of Parents
3) Gametes Produced
4) Genotype of F1 (you may need a Punnett square)
5) Phenotype of F1
6) Gametes from F1 produced
7) Genotype of F2 (you may need a Punnett square)
8) Phenotype of F2
9) What are the ratios of F2 Phenotype and Genotypes

266. Genetic Diagrams – Crossing
3.18 describe patterns of monohybrid inheritance using a genetic diagram
To cross two tall plants
1. The allele for tallness is H and is dominant to that for smallness, h.
2. If the two plants are heterozygous, they will have a genotype, which contains the alleles Hh.
3. Gametes of individuals contain half of the chromosomes. So only one of the alleles will be
present in each gamete cell.
So there will be 3
tall plants for every
1 small plant. Or to
put it another way,
there is a 75%
chance that each F1
(offspring) plant will
be tall.
press

267. TESTCROSS
3.18 describe patterns of monohybrid inheritance using a genetic diagram
Geneticists use the testcross to determine unknown Genotypes
A testcross can reveal an unknown genotype
1. Mate an individual of unknown genotype and a
homozygous-recessive individual
2. In a test cross you breed an organism showing the
dominant features with one showing the recessive
feature
3. Each of the two possible genotypes (homozygous
or heterozygous) gives a different phenotypic ratio
in the F1 generation

268. TESTCROSS
3.18 describe patterns of monohybrid inheritance using a genetic diagram

269. Pedigree Charts
3.19 understand how to interpret family pedigrees
A pedigree is a chart of the genetic history of family over several generations.
Constructing a Pedigree
• Female
• Male
Connecting Pedigree
Symbols
• Married
Couple
• Siblings
• Fraternal
twins
• Identical
twins
• Not Affected
• Affected
• Deceased

270. Example (Dominant or Recessive)
3.19 understand how to interpret family pedigrees
Is the Affected allele Dominant or Recessive?
Affected Unaffected
aa AA
RECESSIVE
Aa Aa Aa
aa aa
aa
Aa Aa
aa aa
aa

271. Example (Dominant or Recessive)
3.19 understand how to interpret family pedigrees
Is the Affected allele Dominant or Recessive?
Affected Unaffected
Aa aa
Aa Aa
DOMINANT
aa aa
Aa Aa Aa
AA
AA aa
Aa

272. Interpreting a Pedigree Chart (hard)
3.19 understand how to interpret family pedigrees
Determine if the pedigree chart shows:
• An autosomal disease
-The disease Allele is not on Sex
Chromosome (X Y)
-The disease Allele can be dominant or
recessive
• X-linked disease
-The disease Allele is found on X Sex
Chromosome
-( X = Normal Allele, Xr = Disease Recessive
Allele)
press
If it is a 50/50 ratio between men and
women. The disorder is autosomal.
Most of the males in the pedigree are
affected. The disorder is X-linked
press

273. Interpreting a Pedigree Chart (additional)
3.19 understand how to interpret family pedigrees
Sex Linked diseases can include:
• Hemophilia (Xr) - Recessive
• Colour blindness (Xr) - Recessive The phenotype of a Carrier
is “NOT DISEASED”

274. Example (Dominant or Recessive)
3.19 understand how to interpret family pedigrees
Example of Pedigree Charts
• Is the affected trait Autosomal or X-linked?
AUTOSOMAL
If it is a 50/50 ratio between men and
women. The disorder is autosomal.

275. Example (Dominant or Recessive)
3.19 understand how to interpret family pedigrees
Summary
• Pedigrees are family trees that explain your genetic
history.
• Pedigrees are used to find out the probability of a
child having a disorder in a particular family.
• To begin to interpret a pedigree, determine if the
disease or condition is autosomal or X-linked and
dominant or recessive.

276. Monohybrid Cross Probability
3.20 predict probabilities of outcomes from monohybrid crosses
GIVE THE GENOTYPE RATIO:
GIVE THE GENOTYPE RATIO:
GIVE THE PHENOTYPE RATIO:

277. Male or Female
3.21 understand that the sex of a person is controlled by one pair of chromosomes, XX in a female and XY in a male

278. Male or Female
3.21 understand that the sex of a person is controlled by one pair of chromosomes, XX in a female and XY in a male
XX = Female
XY = Male

279. Determine the Sex (diagram it)
3.22 describe the determination of the sex of offspring at fertilisation, using a genetic diagram

280. Diploid Cell Division
3.23 understand that division of a diploid cell by mitosis produces two cells which contain identical sets of chromosomes

281. What are homologous chromosomes?
3.23 understand that division of a diploid cell by mitosis produces two cells which contain identical sets of chromosomes
Different organisms have different numbers of chromosomes. Humans
have 46 chromosomes. This is the diploid number of humans.
Chromosomes can be grouped in pairs called homologous
chromosomes. In each pair, one chromosome has been inherited
from the mother and the other inherited from the father.
homologous pair
chromosome from
mother
chromosome from
father

282. What are homologous chromosomes?
3.23 understand that division of a diploid cell by mitosis produces two cells which contain identical sets of chromosomes
2n
Body cells are: 2n - Diploid
Sex Cells are: n - Haploid
2n
2n

283. What is Mitosis good for?
3.24 understand that mitosis occurs during growth, repair, cloning and asexual reproduction
MITOSIS
GROWTH
New cell growth
Nerve cells
(tissue)
Muscle cells
(tissue)
Repair
Scar tissue
Replace old cells
RBC
Skin
Cloning Dolly the sheep
Asexual
Reproduction
Budding
Bacteria & Yeast
Cuttings, Bulbs,
Tubers, Runners
Willow
Tulips
Potatoes
Strawberries

284. Meiosis Makes Gametes
3.25 understand that division of a cell by meiosis produces four cells, each with half the number of chromosomes, and that this results in the
formation of genetically different haploid gametes

285. Meiosis Makes Gametes
3.25 understand that division of a cell by meiosis produces four cells, each with half the number of chromosomes, and that this results in the formation of
genetically different haploid gametes
3.27 know that in human cells the diploid number of chromosomes is 46 and the haploid number is 23
MITOSIS MEIOSIS
1) Produces 2 daughter cells
2) Daughter cells are diploid
(have 23 pairs of chromosomes)
3) Daughter cells are genetically
identical to each other.
3) Gametes are different to
each other
4) Gametes are different to
the parent cell (crossing over of
genetic material)
5) Two stage process
6)Happens in Reproductive
organs only
4) Daughter cells are genetically
identical to the parent cell (no
genetic crossing over)
5) One stage process
6) Happens everywhere in the
body
1) Produces 4 gamete cells
2) Daughter cells are haploid
(Only have 23 chromosomes)

286. Random Fertilization and Variation
3.26 understand that random fertilisation produces genetic variation of offspring

287. Key Word basic Summary
This topic, more than any other, confuses people. Remember these!
DNA: A genetic code
Gene: One instruction in the code telling a cell how to make a
specific protein
Allele: A different version of a gene
Chromosome: Coiled up DNA
Haploid number: the number of different chromosomes in a cell (23)
Diploid number: the total number of chromosomes in a cell (46)
Cell Division:
There are two types of cell division;
- Mitosis – used for growth, repair & asexual reproduction
- Meiosis – used to produce gametes for sexual reproduction

288. Nature Vs Nurture
3.28 understand that variation within a species can be genetic, environmental, or a combination of both
Variation

289. Mutations
(not all x-men get superpowers)
3.29 understand that mutation is a rare, random change in genetic material that can be inherited
3.31 understand that many mutations are harmful but some are neutral and a few are beneficial
Mutation - a rare, random change in the genetic code of a gene.
The mutated gene will produce a slightly different protein to
the original non-mutant gene. The new protein might;
A) Work just as well as it did before (neutral mutation)
B) Work better than before (beneficial mutation)
C) Work worse / not at all (harmful mutation)
Beneficial mutations give a selective advantage to the individual.
Individuals with this kind of mutated allele are more likely to survive,
reproduce and pass their alleles on. This is the basis of:
Natural Selection

290. Evolution by Natural Selection
3.30 describe the process of evolution by means of natural selection
Evolution is the process by which the range of
organisms on Earth change
New species arise through a process known as
NATURAL SELECTION
1) Living organisms produce more offspring than are needed
to replace them, not all of these off-spring grow up and
breed themselves. These offspring have different alleles.
2) Those organisms best suited to their local environment
survive best and breed, passing on their genetic
(genes/DNA) information to the next generation
3) In this way the different forms will become more and
more different until eventually they are a new species

291. WHAT IS THE SELECTION METHOD
3.30 describe the process of evolution by means of natural selection
HOW TO BE SUCCESSFUL IN PASSING ON YOUR
GENES (A HOW TO 5 STEP GUIDE):
1) BE ATTRACTIVE (physical and social traits can make you more
successful with the opposite sex)
2) REPRODUCE OFTEN (The more offspring you make the better)
3) DON’T WASTE YOUR RESOURCES (Invest only the minimal
amount of resources in offspring to see them through to
reproduction)
4) HAVE A ‘DEEP’ GENE POOL (The more variable your offspring
the better chance of some of them surviving unexpected
catastrophes. A little bit of mutation/lots of alleles is not a bad
thing)
5) STAY ALIVE!! (Live long enough to reproduce………....then die.)

292. DARWIN SAID IT BEST
3.30 describe the process of evolution by means of natural selection
Darwin came up with this theory
1) Darwin’s 1st Observation: Not all
individuals survive
2) Darwin’s 2nd Observation: There is
variation in a species
3) Darwin’s Conclusion: The better
adapted individuals survive (the
“fittest”) and reproduce, passing their
alleles onto the next generation.
Over time this process leads to evolution.
www.darwinawards.com/

293. THE SUPERBUGS
3.32 understand that resistance to antibiotics can increase in bacterial populations, and appreciate how such an increase can lead to infections
being difficult to control
1) Bacteria reproduce very frequently so mutations (different alleles) are common.
2) These mutations can mean that they are no longer affected/controlled by a certain
antibiotic
3) Surviving generations carry the mutation (allele)making it easier for them to survive.
4) If bacteria evolve over many generations to be resistant to drugs we are treating
them with then they are difficult to control
5) Sometimes they can be controlled using a different antibiotic
6) These bacteria in turn become resistant to new antibiotics due to the high rate or
reproduction and random mutations
7) Currently some are becoming resistant to all current know antibiotics.
Methicillin-resistant Staphylococcus aureus (MRSA or golden staph), vancomycin-resistant
Enterococcus (VRE) and multi-drug-resistant Mycobacterium tuberculosis (MDR-TB)
✔

294. The Makings of a Mutant (TA)
3.33 understand that the incidence of mutations can be increased by exposure to ionising radiation (for example gamma rays, X-rays and
ultraviolet rays) and some chemical mutagens (for example chemicals in tobacco).(TA)
Mutations are: a) inherited b) happen on their own
(although this is rare).
The frequency that mutation occurs naturally can be
increased by exposure to radiation
• gamma rays
• X-rays
• ultraviolet rays
And
Chemical mutagens
• chemicals in tobacco..Not Nicotine!)

295. Ecology & Environment

296. Definitions
4.1 understand the terms population, community, habitat and ecosystem
• Population: all the individuals of a particular
species within a defined area
• Community: a group of different populations
living in the same area
• Habitat: the physical, chemical and biological
environment in which an organism lives
• Ecosystem: a community of living things and
the environment in which they live

297. How to Use a Quadrat (1)
4.2 explain how quadrats can be used to estimate the population size of an organism in two different areas
4.3 explain how quadrats can be used to sample the distribution of organisms in their habitats.
• A quadrat can be used to calculate
the total population of a species
(e.g. snails).
• Simply count the number of
individuals in the quadrat.
• This technique only works for large
organisms which can be
distinguished as individuals and do
not move fast (not always easy for
plants, e.g. grass and tigers)

298. How to Use a Quadrat (2)
4.2 explain how quadrats can be used to estimate the population size of an organism in two different areas
4.3 explain how quadrats can be used to sample the distribution of organisms in their habitats.
• A quadrat can be used to
calculate the percentage cover
of a species (e.g. moss).
• The quadrat is divided into
100 smaller squares.
• The percentage cover of the
quadrat is simply the number
of squares filled with the
species.

299. How to Use a Quadrat (3)
4.2 explain how quadrats can be used to estimate the population size of an organism in two different areas
4.3 explain how quadrats can be used to sample the distribution of organisms in their habitats.
• A quadrat can be used to
calculate the percentage
frequency of a species (e.g.
daisies in a field).
• The quadrat is divided into 100
smaller squares. You simply count
a 1 for each square the species is
in and a 0 for those where it is
absent.
• This gives you an indication of the
frequency of the species, it does
not tell you the total population.

300. USE of A Sample Quadrat
4.2 explain how quadrats can be used to estimate the population size of an organism in two different areas
4.3 explain how quadrats can be used to sample the distribution of organisms in their habitats.
The best use of a quadrat is in obtaining a sample
(it is not practical to count all of the species)
e.g. one cannot count all of the grass plants in a field!
Ecologists use quadrats to sample from a habitat.

301. You can use the data to:
4.2 explain how quadrats can be used to estimate the population size of an organism in two different areas
4.3 explain how quadrats can be used to sample the distribution of organisms in their habitats.
Compare different species in ONE
area
Compare the same species in TWO
or MORE areas

302. Using a Quadrat
4.2 explain how quadrats can be used to estimate the population size of an organism in two different areas
4.3 explain how quadrats can be used to sample the distribution of organisms in their habitats.
Sampling:
1) Sample has to be random (so no bias is
introduced).
2) Samples have to be representative, so we have to
take a large enough sample. At least 5% of
habitat.

303. Using a Quadrat
4.2 explain how quadrats can be used to estimate the population size of an organism in two different areas
4.3 explain how quadrats can be used to sample the distribution of organisms in their habitats.
How to make a quadrat sample?
• Find the boarders of your habitat (measure)
• Divide your habitat into a grid with X and Y coordinates.
• Randomly place your quadrat (use a random numbers for X & Y
coordinates)
• Count number or organism/organisms, percentage cover or
frequency of organisms.
• Record all data in a table.
• Repeat until a large enough sample size is completed
• Average all data
• Scale up average (multiply average per quadrat by number of
quadrats in habitat)
• Compare:
1. Different species in same habitat
2. Same species from a different habitat

304. Review from the past
4.4 explain the names given to different trophic levels to include producers, primary, secondary and tertiary consumers and decomposers

305. Feeding Relationships
4.4 explain the names given to different trophic levels to include producers, primary, secondary and tertiary consumers and decomposers
Food chains are used to show the relationships
between species in a habitat. E.g.
The secondary Consumer (eats the Primary
Consumer)
The Primary Consumer (eats the producer)
The Primary Producer (all food chains start with this)
FOX
RABBIT
GRASS
Each level in a food chain is called a Trophic Level

306. Definitions of Different Trophic levels
4.4 explain the names given to different trophic levels to include producers, primary, secondary and tertiary consumers
and decomposers
• Producers:
Plants (use sunlight to obtain nutrients)
• Primary Consumer:
Herbivores (plant eaters)
• Secondary Consumer:
Carnivore (animal / herbivore eaters)
• Tertiary Consumer:
Carnivore (animal / carnivore eaters)
• Decomposers:
Usually a bacterium or fungi, that breaks down the cells of
dead plants and animals into simpler substances.

307. FOOD WEBS
4.5 understand the concepts of food chains, food webs, pyramids of number, pyramids of biomass and pyramids of energy transfer
Food chains can be built up into complex food
webs. The difference between food chains and
food webs is that food webs have branches,
chains never do.

308. A Pyramid of Numbers
4.5 understand the concepts of food chains, food webs, pyramids of number, pyramids of biomass and pyramids of energy transfer
In a pyramid of numbers, the length of each bar
represents the number of organisms at each
trophic level in a specified area.

309. Pyramid of numbers (complex)
4.5 understand the concepts of food chains, food webs, pyramids of number, pyramids of biomass and pyramids of energy transfer

310. Pyramid of Biomass
4.5 understand the concepts of food chains, food webs, pyramids of number, pyramids of biomass and pyramids of energy transfer
In a pyramid of biomass, the length of each bar represents the
amount of organic matter – biomass – at each trophic level in a
specified area.
At each trophic level, the amount of biomass and
energy available is reduced, giving a pyramid shape.

311. Pyramid of Biomass
4.5 understand the concepts of food chains, food webs, pyramids of number, pyramids of biomass and pyramids of energy transfer

312. Compare Numbers to Biomass
4.5 understand the concepts of food chains, food webs, pyramids of number, pyramids of biomass and pyramids of energy
transfer

313. Pyramid of Energy
4.5 understand the concepts of food chains, food webs, pyramids of number, pyramids of biomass and pyramids of energy transfer
• It is a graphical representation of the trophic levels,
by which the incoming solar energy is transferred to
the ecosystem.
• It shows the total energy flow in the ecosystem.
• There does not exist an inverted energy pyramid.

314. Pyramid of Energy
4.5 understand the concepts of food chains, food webs, pyramids of number, pyramids of biomass and pyramids of energy transfer
4.6 understand the transfer of substances and of energy along a food chain
4.7 explain why only about 10% of energy is transferred from one trophic level to the next.
Energy is never ‘lost’, it is transferred.
Not all the energy is transferred to the next
stage is converted into growth.

315. Pyramid of Numbers, Biomass & Energy
4.5 understand the concepts of food chains, food webs, pyramids of numbers, pyramids of biomass and pyramids of energy transfer

316. Cycles within Ecosystems
4.8 describe the stages in the water cycle, including evaporation, transpiration, condensation and precipitation (TA)
transpiration

317. Some quick definitions
4.8 describe the stages in the water cycle, including evaporation, transpiration, condensation and precipitation (TA)
Evaporation: To change from a liquid or solid state
into vapour.
Condensation: To become liquid or solid, as a gas or
vapour.
Precipitation: Rain, snow, sleet, dew, etc, formed
by condensation of water vapour in the
atmosphere.
Transpiration: The passage of watery vapour
through the skin or through any membrane or pore
in plants.

318. CARBON CYCLE
4.9 describe the stages in the carbon cycle, including respiration, photosynthesis, decomposition and combustion

319. Some quick definitions
4.9 describe the stages in the carbon cycle, including respiration, photosynthesis, decomposition and combustion
• Respiration : The process in living organisms of
taking in oxygen from the surroundings and
giving out carbon dioxide (external respiration).
• Photosynthesis : The synthesis of organic
compounds from carbon dioxide and water (with
the release of oxygen) using light energy
absorbed by chlorophyll.
• Decomposition : To break down (organic matter)
physically and chemically by bacterial or fungal
action.
• Combustion : The process of burning

320. NITROGEN CYCLE
4.10 describe the stages in the nitrogen cycle, including the roles of nitrogen fixing bacteria, decomposers, nitrifying bacteria and
denitrifying bacteria (specific names of bacteria are not required). (TA)

321. NITROGEN CYCLE
4.10 describe the stages in the nitrogen cycle, including the roles of nitrogen fixing bacteria, decomposers, nitrifying bacteria and
denitrifying bacteria (specific names of bacteria are not required). (TA)

322. NITROGEN CYCLE
4.10 describe the stages in the nitrogen cycle, including the roles of nitrogen fixing bacteria, decomposers, nitrifying bacteria and
denitrifying bacteria (specific names of bacteria are not required). (TA)

323. NITROGEN CYCLE
4.10 describe the stages in the nitrogen cycle, including the roles of nitrogen fixing bacteria, decomposers, nitrifying
bacteria and denitrifying bacteria (specific names of bacteria are not required). (TA)

324. Nitrogen Cycle
4.10 describe the stages in the nitrogen cycle, including the roles of nitrogen fixing bacteria, decomposers, nitrifying bacteria and denitrifying bacteria
(specific names of bacteria are not required). (TA)
This is not particularly easy to understand. You need to
know the roles of all the different bacteria. There are 4;
• Decomposers – turn nitrogen in protein into ammonium
+)
(NH4
-) into Nitrites
• Denitrifying Bacteria – turn Nitrates (NO3
-) into ammonium (NH4
(NO2
+ ) into Nitrogen gas (N2)
+) into nitrites
• Nitrifying bacteria – turn ammonium (NH4
-) and then nitrates (NO3
(NO2
-)
+)
• Nitrogen-fixing bacteria – turn N2 into ammonium (NH4

325. WAIT!!!
4.10 describe the stages in the nitrogen cycle, including the roles of nitrogen fixing bacteria, decomposers, nitrifying bacteria and denitrifying bacteria (specific names of
bacteria are not required). (TA)
There is more that you are not expected to know from
your syllabus, but may be included as additional
information in your exam on the Nitrogen Cycle
• Extension - leguminous plants
• All of the above bacteria are naturally present in the
soil. The only exception to this is that some Nitrogen-fixing
bacteria (e.g. Rhizobium) live in the roots of
some plants. These plants are called legumes (e.g.
peas, clover etc). They have a symbiotic relationship
with the bacteria i.e. both the bacteria and the plant
benefit from working together.

326. Human influences on the environment
4.11 understand the biological consequences of pollution of air by sulfur dioxide and by carbon monoxide
Acid rain:
SO2, CO2 and NOx (oxides of nitrogen) dissolve in
rain to form Sulphuric Acid, Carbonic Acid and
Nitric Acid.
This falls as acid rain, which destroys soil,
pollutes waterways and causes erosion.

327. BIOLOGICAL CONSEQUENCES
4.11 understand the biological consequences of pollution of air by sulfur dioxide and by carbon monoxide
1) Acid rain can 'burn' trees. This stops photosynthesis.
2) Sulphuric acid causes Calcium and Magnesium to be
leached out of the soil. Without Calcium and Magnesium
ions in the soil plant’s leaves turn yellow/wither and the
plant can't grow.
3) Reduce the pH of the streams & lakes. The affect is
that it releases aluminum ions (Al3+) which causes the
thickening of mucus in the fishes gills. Fish have difficulty
in obtaining oxygen. The fish numbers decrease.

328. CO
4.11 understand the biological consequences of pollution of air by sulfur dioxide and by carbon monoxide
Carbon Monoxide (CO) is a gas added to the atmosphere
by the combustion of fossil fuels (particularly coal)
burned with insufficient oxygen.
• Carbon monoxide combines with our hemoglobin
inside our blood and blocks hemoglobin from carrying
oxygen which reduces oxygen circulation.
• This is toxic, too much carbon monoxide can be fatal.

329. Greenhouse Gasses
4.12 understand that water vapour, carbon dioxide, nitrous oxide, methane and CFCs are greenhouse gases
4.13 understand how human activities contribute to greenhouse gases

330. Global Warming
4.14 understand how an increase in greenhouse gases results in an enhanced greenhouse effect and that this may lead to
global warming and its consequences
Greenhouse gases trap heat around the surface
of the Earth and are needed to keep the planet
warm enough for life.
1) Incoming shortwave radiation passes through the atmosphere and
hits the Earth, where it is absorbed. (LIGHT)
2) The Earth re-emits the radiation as longer-wavelength Infra-Red
radiation. (HEAT)
This is the problem.
3) Too much IR radiation is absorbed by greenhouse gases on its way
out of the atmosphere. This traps the too much heat in the
atmosphere.

331. GREENHOUSE EFFECT
GOOD
4.14 understand how an increase in greenhouse gases results in an enhanced greenhouse effect and that this may lead to global warming and its consequences

332. GREENHOUSE EFFECT
BAD
4.14 understand how an increase in greenhouse gases results in an enhanced greenhouse effect and that this may lead to globalwarming and its
consequences

333. GREENHOUSE EFFECT
4.14 understand how an increase in greenhouse gases results in an enhanced greenhouse effect and that this may lead to global warming and its
consequences
The theory goes that the greenhouse effect is causing
global warming, which is bad. Global warming might
cause:
a) Polar ice cap melting (Sea levels rising)
b) Extinction of species living in cold climates
c) Changes in rainfall (both droughts and flooding)
d) Changes in species distribution (i.e. tropical species
spreading, like mosquitoes)

334. Eutrophication
4.15 understand the biological consequences of pollution of water by sewage, including increases in the number of micro-organisms
causing depletion of oxygen (TA)
4.16 understand that eutrophication can result from leached minerals from fertiliser
Eutrophication is what happens when too much chemical
fertiliser is used on crops and it washes/leaches into rivers
and streams.
(also nitrates can come from sewage)
1) The nitrates in the fertilisers are essential to get crops to
grow well and increase yields.
NITRATES ADDED
2) However, if too much is used, or it rains soon after it is
added to fields, the fertiliser gets washed away.
RUN OFF
3) The nitrates then help plants in the rivers and streams to
grow very quickly, especially algae.
ALGAL BLOOM

335. 4) But after the initial massive growth in algae
there isn't enough light and water plants die
MASSIVE PLANT DEATH
5) Without sunlight and when the nitrates run
out MOST of the algae die
MASSIVE ALGAL DECAY
6) All those dead plant start to decay. Respiring
bacteria remove oxygen from the water.
ANOXIC CONDITIONS
7) No Oxygen kills fish and other animals.
ANIMAL DEATH AND DECAY

336. 8) Then even more algae and animals die.
MORE DEATH & DECAY
9) pH levels fall as decomposition produces acids
pH DROPS
10) Everything dies and waterway can no longer
support life
TOTAL DEATH
So farmers have to be very careful using fertilisers
so as not to wipe out all river and lake life.

337. Simply but Clearly
4.15 understand the biological consequences of pollution of water by sewage, including increases in the number of micro-organisms causing
depletion of oxygen (TA)
Nitrates >
Algae Grow >
Algae Die >
Algae Decay >
No Oxygen >
Fish &
Animals Die

338. Deforestation
4.17 understand the effects of deforestation, including leaching, soil erosion, disturbance of the water cycle and of the
balance in atmospheric oxygen and carbon dioxide
Cutting down trees and not replacing causes:
• Leaching of soil minerals
• Soil erosion / washed and blown away (no roots
holding soil together)
• Desertion (new deserts forming)
• Disturbance of the water cycle (less transpiration
can lead to flooding and / or drought)
• Increase in CO2 levels
Less photosynthesis
• Decrease in O2 production
Burning trees

340. Section 5
Use of Biological Resources
• a) Food production
• b) Selective breeding
• c) Genetic modification (genetic engineering)
• d) Cloning

341. Food production
CROP PLANTS
5.1 describe how glasshouses and polythene tunnels can be used to increase the yield of certain crops
5.2 understand the effects on crop yield of increased carbon dioxide and increased temperature in glasshouses
Greenhouses and polythene tunnels raise the temperature, which increases
the rate of photosynthesis, which increases crop yield.
(Yield - The total mass of the edible part of crop.)
1) If the level of CO2 in the greenhouse is increased  the yield will further
increase .
2) Heating units increase temperature and CO2. (combustion)
(remember, CO2 is a limiting factor in photosynethsis)
3) In winter months using artificial lights gives a ‘longer day’ for growing
4) Transparent glass and plastic allow short wave energy in (light) and reflect
long wave energy back (heat) to keep temperature high.

342. Glasshouses and Polythene tunnels
5.1 describe how glasshouses and polythene tunnels can be used to increase the yield of certain crops
5.2 understand the effects on crop yield of increased carbon dioxide and increased temperature in glasshouses

343. What is grown
5.1 describe how glasshouses and polythene tunnels can be used to increase the yield of certain crops
High value crops are grown in polythene tunnels and
greenhouses.
Some examples are:
• Strawberries
• Tomatoes
• Flowers
Only high value crops make sense to grow in this intensive
way.
(Value of crop must exceed cost of production)

344. Fertilizer and Crop Yield
5.3 understand the use of fertiliser to increase crop yield
If fertilizers are added (specifically those that contain
Potasium, Nitrate and Phosphate– KNP fertilisers) then
the yield will increase even more!
Potassium – essential for plant membranes
Nitrate – essential for making plant
proteins
Phosphate – essential for DNA and membranes

345. Fertilizer and Crop Yield
5.3 understand the use of fertiliser to increase crop yield
• Nitrogen is used to make
protiens
• Proteins increase biomass (more
plant)
• Increase in biomass increases
marketable part of the crop
( on a plant)
• Increased crop increases revenue
(the cost of fertilizer must be less
then the increase in value of the
crop)

346. Eutrophication again
Simply but Clearly
5.3 understand the use of fertiliser to increase crop yield
Nitrates >
Algae Grow >
Algae Die >
Algae Decay >
No Oxygen >
Fish &
Animals Die

347. Pest Control
5.4 understand the reasons for pest control and the advantages and disadvantages of using pesticides and biological control with
crop plants
Pest Control can also be used to increase Yield. This can be done
either using pesticides or biological controls.
• Pesticide – a chemical that kills pests (anything that eats your
crop), but does not harm the crop plant
• Biological control – introducing a biological organism which will
eat the pest, but not the crop plant (e.g. birds are sometimes
encouraged inside greenhouses because they eat caterpillars)

348. Name some –cides
5.4 understand the reasons for pest control and the advantages and disadvantages of using pesticides and biological control with crop plants
• Herbicides
• Insecticides
• Fungicides
• Molluscicides
• Fratricides
• Suicides
• Homicide
• Uxoricide
• Matricide
• Patricide
• Vatricide
• Deicide
• Tomeicide
• Mundicide
Plants
Insects
Fungi
Shellfish
Brother
Self
Person
Wife
Mother
Father
Poets
God
Books
Everything

349. Pesticides
5.4 understand the reasons for pest control and the advantages and disadvantages of using pesticides and biological control with crop plants
Disadvantages of using pesticides:
• pesticides may enter and
accumulate in food chains
• pesticides may harm organisms
which are not pests
• some pesticides are persistent.
DDT

350. Biological Control
5.4 understand the reasons for pest control and the advantages and disadvantages of using pesticides and biological control with crop plants
Advantages and disadvantages of
biological control, to include:
• advantages:
– no need for chemical pesticides
– does not need repeated treatment
• disadvantages:
– predator may not eat pest
– may eat useful species
– may increase out of control
– may not stay in the area where it is
needed.

351. Micro Organisms
5.5 understand the role of yeast in the production of beer
Yeast
Remember that yeast are capable of respiring
1) aerobically (producing CO2 and water)
&
2) anaerobically (producing CO2 and ethanol).
Yeast are therefore used in the brewing industry.

352. MAKING BEER
5.5 understand the role of yeast in the production of beer
In order to make beer:
• barley seeds are allowed to germinate by soaking
them in warm water (This is called malting).
• The germinating barley seeds break down their
carbohydrate stores, releasing sugar.
• After a couple of days the barley seeds are gently
roasted (which kills them).
• The dead seeds are put into a fermenter with
yeast.
• The yeast use the sugar for anaerobic respiration
and produce ethanol.

353. Well it’s beer

354. EXPERIMENT
5.6 describe a simple experiment to investigate carbon dioxide production by yeast, in different conditions
You need to know:
An experiment that shows the production of CO2 by yeast, in
different conditions:
IV (choose one and keep the others constant):
a) Type of sugar
b) Concentration of sugar (mass meter/measuring cylinder - %)
c) Temperature of solution (thermometer – 0C)
DV (Measure one):
a) Height of frothy bubbles (ruler - cm)
b) Volume of CO2 produced (gas syringe - mL)
c) Volume of CO2 from delivery tube to inverted container over
water (graduated cylinder – mL)
The best example is to mix a yeast suspension with sucrose
Any CO2 produced can be collected over water or bubbled through
lime water or hydrogen carbonate indicator

355. 5.6 describe
a simple
experiment
to investigate
carbon
dioxide
production by
yeast, in
different
conditions

356. Graphs and Limiting Factors
5.6 describe a simple experiment to investigate carbon dioxide production by yeast, in different conditions
The rate of CO2 production levels off in the
experiments over time.
Reason:
1) Sugar (glucose/sucrose) is a limiting factor
2) Ethanol is produced which is toxic to micro-organisms
(yeast)

357. MAKING YOGHURT
5.7 understand the role of bacteria (Lactobacillus ) in the production of yoghurt (TA)
Lactobacillus bacterium is This bacterium is used to turn milk
into yoghurt.
It uses lactose sugar in the milk to produce lactic acid by
anaerobic respiration.
A. The lactic acid affects the milk proteins, making the
yoghurt curdle (go solid) and giving it the characteristic
tart taste.
B. lowers the pH of milk to inhibit harmful to human
bacterial growth

358. Industrial Fermenters
5.8 interpret and label a diagram of an industrial fermenter and explain the need to provide suitable conditions in the fermenter,
including aseptic precautions, nutrients, optimum temperature and pH, oxygenation and agitation, for the growth of micro-organisms
(TA)
Fermenters are huge containers that hold up to 200,000dm3 of liquid.
They make it possible to control the environmental conditions such as:
1. Temperature
2. Oxygen
3. Carbon Dioxide concentrations
4. pH
5. Nutrient levels
This allows microorganisms can grow and respire
without being limited and can work as efficiently as
possible
(High Yield)

359. MAKING MONEY FROM BACTERIA
5.8 interpret and label a diagram of an industrial fermenter and explain the need to provide suitable conditions in the fermenter, including
aseptic precautions, nutrients, optimum temperature and pH, oxygenation and agitation, for the growth of micro-organisms (TA)
It is very important the everything in the
fermenter is sterile, so that only the
microorganisms that are wanted grow in the
culture.
Fermenters are used to produce commercially:
• Penicillin (antibiotic) in aerobic conditions
• Beer (ethanol) in anaerobic conditions
• Yoghurt (lactic acid) in anaerobic conditions

360. FERMENTER
5.8 interpret and label a diagram of an industrial fermenter and explain the need to provide suitable conditions in the fermenter, including aseptic
precautions, nutrients, optimum temperature and pH, oxygenation and agitation, for the growth of micro-organisms (TA)
Important details:
Water Cooling jacket – keeps the microorganisms at optimum temperature.
They will produce lots of heat through respiration, therefore need to be
cooled!
Paddles – keep stirring the mixture. This stops waste products from building up
and keeps the air evenly mixed
Nutrient medium – supplies the microorganisms with fuel for respiration
Sterile Air supply – supplies clean O2 for respiration (note: this is not required
in anaerobic fermentation processes)
Data-logger – monitors temperature and pH, keeps the fermenter at optimum
conditions

361. Fermenter Diagram
5.8 interpret and label a diagram of an industrial fermenter and explain the need to provide suitable conditions in the fermenter, including aseptic
precautions, nutrients, optimum temperature and pH, oxygenation and agitation, for the growth of micro-organisms (TA)
You don’t need to be
able to draw this out,
but you could be
asked to label a
diagram of a
fermenter or be
asked to explain the
function of the
various parts of a
fermenter.

362. STOPPING THE O2, RELEASING CO2
5.8 interpret and label a diagram of an industrial fermenter and explain the need to provide suitable conditions in the fermenter, including
aseptic precautions, nutrients, optimum temperature and pH, oxygenation and agitation, for the growth of micro-organisms (TA)
The valve
• releases CO2 under pressure
• stops Oxygen and
microorganisms from entering

363. Why Fish farming(overview)
5.9 explain the methods which are used to farm large numbers of fish to provide a source of protein, including maintenance of water quality, control of
intraspecific and interspecific predation, control of disease, removal of waste products, quality and frequency of feeding and the use of selective breeding.
• Control feeding diet quality and frequency
• Control water quality, temperature and waste removal
• Control predation
• Control disease and parasites
• Select for species, size and quality
• No boats needed and a guaranteed harvest
• Less overfishing of natural wild fish stocks
• No risk of catching unwanted (non-marketable species)

364. Fish farming
5.9 explain the methods which are used to farm large numbers of fish to provide a source of protein, including maintenance of water quality, control of
intraspecific and interspecific predation, control of disease, removal of waste products, quality and frequency of feeding and the use of selective breeding.
Fish are farmed in fish farms because they are a
good source of protein.
1) Fish farms keep lots of fish in very small tanks to
minimize space requirements.
2) To stop the fish fighting with each other these
precautions are taken;

365. Fish farming
5.9 explain the methods which are used to farm large numbers of fish to provide a source of protein, including maintenance of water quality, control of
intraspecific and interspecific predation, control of disease, removal of waste products, quality and frequency of feeding and the use of selective breeding.
To reduce predation:
• Nets cover tanks
• Barriers separate tanks

366. Basic Points
5.9 explain the methods which are used to farm large numbers of fish to provide a source of protein, including
maintenance of water quality, control of intraspecific and interspecific predation, control of disease, removal of waste
products, quality and frequency of feeding and the use of selective breeding.
- Different fish species are kept in
separate tanks. This stops
competition between species of
fish (interspecific competition)
- Fish of different genders are kept
separately (unless they are being
bred)
- Fish of different ages are kept
separately. This stops competition
between fish of the same species
(intraspecific competition)

367. INCREASING YIELD
5.9 explain the methods which are used to farm large numbers of fish to provide a source of protein, including maintenance of water quality,
control of intraspecific and interspecific predation, control of disease, removal of waste products, quality and frequency of feeding and the use of
selective breeding.
The fish are fed often and in small amounts, or fed with
protein-rich food
(where does the protein come from?)
Sometimes hormones are added to the water to speed
growth.
Only the biggest and most healthy fish are allowed to
breed.
(The small and unhealthy fish end up as fish food.)
This is an example of selective breeding.

368. INCREASING YIELD, DECREASING DISEASE, MAKING
SUPERBUGS AND AFFECTING CONSUMERS
5.9 explain the methods which are used to farm large numbers of fish to provide a source of protein, including maintenance of water quality, control of intraspecific and
interspecific predation, control of disease, removal of waste products, quality and frequency of feeding and the use of selective breeding.
The use of antibiotics will increase the rate of growth (yield) &
decrease incidence of disease.
Pesticides decrease the growth and spread of parasites
Negatives:
1. It can also selectively breed antibiotic resistant bacteria.
2. Pesticides can kill other invertebrates
3. Pollution from organic material leads to eutrophication
4. Antibiotics may not degrade and can be passed on to
consumers (humans).

369. DECREASING DISEASE
5.9 explain the methods which are used to farm large numbers of fish to provide a source of protein, including maintenance of water quality,
control of intraspecific and interspecific predation, control of disease, removal of waste products, quality and frequency of feeding and the use of
selective breeding.
Water is closely monitored.
Fish are continuously supplied with fresh sterile
water so that wastes and excess nutrients are
washed out constantly.
The fish are kept in sterile water to limit disease,
which would spread very quickly in the cramped
ponds.

370. DECREASING DISEASE
5.9 explain the methods which are used to farm large numbers of fish to provide a source of protein, including maintenance of water quality,
control of intraspecific and interspecific predation, control of disease, removal of waste products, quality and frequency of feeding and the use of
selective breeding.
C:
O:
R:
M:
M:
S:
Question
Answer Notes Marks
C different temperatures / eq;
O same species / size/ age/gender/eq;
R repeat / eq;
M1 mass / length / number / eq;
M2 time period stated;(one day minimum)
S1 and S2 same food type / same food mass /
same oxygen / tank size /
fish density stated / eq;;
6
Total 6

371. Selective Breeding
5.10 understand that plants with desired characteristics can be developed by selective breeding
5.11 understand that animals with desired characteristics can be developed by selective breeding.

372. Definition
5.10 understand that plants with desired characteristics can be developed by selective breeding
5.11 understand that animals with desired characteristics can be developed by selective breeding.
Selective Breeding:
a. Individuals with desired characteristics are
bred together
b. This is to produce offspring which express
desired characteristics.
c. Offspring with desired characteristics are
bred
d. Repeat over many generations

373. Examples:
Examples
5.10 understand that plants with desired characteristics can be developed by selective breeding
5.11 understand that animals with desired characteristics can be developed by selective breeding.
Increased yield and reduction of stem length in wheat
Increased yield of meat and milk in cattle.

374. Selective Breeding Points
5.10 understand that plants with desired characteristics can be developed by selective breeding
5.11 understand that animals with desired characteristics can be developed by selective breeding.
• Process of controlled sexual reproduction
• Potentially can take thousands of years
• Can lead to huge variation in a species.
Example: dog family

375. Selective Breeding
(a simple how to guide…. again)
5.10 understand that plants with desired characteristics can be developed by selective breeding
5.11 understand that animals with desired characteristics can be developed by selective breeding.
• Identify individual organisms that have a
desirable trait in a population.
• Breed these individuals together.
• From offspring choose those with the
desirable trait.
• Breed these offspring together.
• Continue for a long, long, long time

376. Genetic Modification
Syllabus points 5.12 – 5.20

377. Genetic
Modification
Syllabus points 5.12 – 5.20
Review the
structure of DNA:
DNA is a double-stranded molecule. The strands coil up to form a double-helix. The strands are
linked by a series of paired bases.
Thymine (T) pairs with Adenine (A)
Guanine (G) pairs with Cytosine (C)

378. Process of Genetic Engineering
5.14 understand that large amounts of human insulin can be manufactured from genetically modified bacteria that are grown in a fermenter
The example you need to know is the creation of E coli
bacteria that makes human insulin.
However, a more fun example is Alba, the glow-in-the-dark
bunny, and pigs that makes the protein luminol (FGP)
(taken from a jellyfish!)

379. TRANSGENIC ORGANISMS
5.12 describe the use of restriction enzymes to cut DNA at specific sites and ligase enzymes to join pieces of DNA together
The organism that receives the new gene from a
different species is a transgenic organism.

380. PROCESS
5.12 describe the use of restriction enzymes to cut DNA at specific sites and ligase enzymes to join pieces of DNA together
1) Plasmids are isolated from a bacterium.
2) They are cut open with a specific restriction
enzyme.
3) The gene to be transferred is cut from the donor
DNA using the same restriction enzyme, so that the
plasmid and the gene have the same sticky ends and
can be joined together. (ends match)

381. PROCESS
5.12 describe the use of restriction enzymes to cut DNA at specific sites and ligase enzymes to join pieces of DNA together
4) The 'opened-up' plasmids and the isolated gene are
mixed with a DNA ligase enzyme to create
recombinant plasmids.
5) Bacteria are incubated
with the recombinant DNA.
6) Some bacteria will take up the plasmids.

382. PROCESS
5.12 describe the use of restriction enzymes to cut DNA at specific sites and ligase enzymes to join pieces of DNA together
7) The bacteria that have
taken up the plasmid now
contain the gene from the
donor cell. This could be a
gene controlling the
production of human
insulin.
8) So the bacterium is
transgenic.

383. Making a Transgenic Bacterium
5.12 describe the use of restriction enzymes to cut DNA at specific sites and ligase enzymes to join pieces of DNA together
On your diagram include the enzymes used to ‘cut’ and ‘stitch’ back to
together the DNA. Include where the Vector would be used.

384. 5.13 describe how plasmids and viruses can act as vectors, which take up pieces of DNA, then insert this recombinant DNA into other cells
• Common vectors include Viruses and
Plasmids
• Now your transgenic bacterium is complete.
All you need to do is grow it in a fermenter
and it makes lots of insulin for you!

385. Putting it all together
5.12 describe the use of restriction enzymes to cut DNA at specific sites and ligase enzymes to join pieces of DNA together

386. Transgenic Organism
5.16 understand that the term transgenic means the transfer of genetic material from one species to a different species. (TA)
Organism containing DNA from two or more sources
(i.e. an organism that’s been genetically engineered to
express a foreign gene)
Plants are good to genetically engineer because they
are more simple and there are fewer ethical issues.

387. Genetically modified (GM) crops are engineered to:
5.15 evaluate the potential for using genetically modified plants to improve food production (illustrated by plants with improved resistance to pests)
• Have bigger yields
• Produce their own insecticide
• Be frost resistant (e.g. frost resistant strawberries)
• Have resistance to disease
• Grow in harsher environments (e.g. drought-resistant rice)
• Grow in harsher environments (e.g. salt resistant wheat)
• Have a longer sell-by date (e.g. non-squash tomatoes)
• Be a different colour / taste to normal (e.g. chocolate
flavoured carrots)
• Have vitamins in them that they would not normally have
(e.g. golden rice)
• Have stronger taste (e.g. chilli's)
• Be easier to eat (e.g. easy-peel oranges)

388. CLONING
Syllabus points 5.17 – 5.20
Cloning is used to make many copies of a single
individual. Usually the individual has a very desirable
phenotype and has often been produced at the end
of a Selective Breeding or GE programme.
CLONES ARE: Genetically Identical Organisms
Start
2min

389. Cloning in Plants
5.18 understand how micropropagation can be used to produce commercial quantities of identical plants (clones) with desirable characteristics
The easiest way to clone a plant is to take a cutting or
a graft (asexual reproduction).
However, micro propagation (tissue culture) can be
used in large-scale cloning programmes.
Which desirable characteristics in cloned plants do you want
to express (selective breeding vs GM)?

390. Diagram of Propagation
5.17 describe the process of micropropagation (tissue culture) in which small pieces of plants (explants) are grown in vitro using nutrient media

391. Diagram of Propagation
5.17 describe the process of micropropagation (tissue culture) in which small pieces of plants (explants) are grown in vitro using nutrient media

392. Micro propagation
5.17 describe the process of micropropagation (tissue culture) in which small pieces of plants (explants) are grown in vitro using nutrient media
1) Micro-propagation - small pieces of plants
(explants) or tissue samples are grown in a Petri dish
on nutrient medium (agar).
Growing a living organism in an artificial
environment is called In Vitro.
2) Hormones / bleach are added to the explant so it
will grow into a miniature plant (a plantlet).
3) This can be done on a huge scale to produce
1000s of plantlets from a single culture.

393. Diagram of Propagation
5.17 describe the process of micropropagation (tissue culture) in which small pieces of plants (explants) are grown in vitro using nutrient media
How do you draw it?
Include vocabulary:
Auxin/Bleach
Nutrient agar
In Vitro
Cutting/Tissue Sample/explants
Plantlets
(you can include more)

394. Advantages and Disadvantages to clones
5.17 describe the process of micropropagation (tissue culture) in which small pieces of plants (explants) are grown in vitro using nutrient media

395. Animal Cloning
5.19 describe the stages in the production of cloned mammals involving the introduction of a diploid nucleus from a mature cell into an
enucleated egg cell, illustrated by Dolly the sheep
• Take an embryonic cell
• Remove it’s nucleus (enucleate it)
• Replace with the nucleus from an adult cell (from the
animal you want to clone)
• Give it an electrical shock
• The embryonic cell grows into an embryo clone of the
adult, from which the donor nucleus came

396. Animal Cloning
5.19 describe the stages in the production of cloned mammals involving the introduction of a diploid nucleus from a mature cell into an
enucleated egg cell, illustrated by Dolly the sheep
This process was used to create Dolly the
sheep

397. Animal Cloning
5.19 describe the stages in the production of cloned mammals involving the introduction of a diploid nucleus from a mature cell into an
enucleated egg cell, illustrated by Dolly the sheep

398. WHY CLONE?
5.20 evaluate the potential for using cloned transgenic animals, for example to produce commercial quantities of human antibodies or organs
for transplantation. (TA)
Cloning can be used beneficially in agriculture to
increase the yield of crop plants.
Cloning genetically engineered animals organisms
allows us to mass-produce very useful organisms
e.g. the E. coli bacterium that makes human insulin
has been cloned many times.
Now all diabetics have access to human insulin.

399. Making Insulin
5.20 evaluate the potential for using cloned transgenic animals, for example to produce commercial quantities of human antibodies or organs
for transplantation. (TA)

400. Human antibodies
5.20 evaluate the potential for using cloned transgenic animals, for example to produce commercial quantities of human antibodies or organs
for transplantation. (TA)
To make human antibodies:
1.Create transgenic mice
with human DNA (for
immune system)
2.Infect mice with disease
3.Mice produce human
antibodies to disease
4.Collect mouse blood and
remove antibodies
5.Inject sick humans with
antibodies
1)Milk it or Bleed it
2)Can give more blood

401. COMMERCIAL ORGANS FROM CLONES!!!!
5.20 evaluate the potential for using cloned transgenic animals, for example to produce commercial quantities of human antibodies or organs for
transplantation. (TA)
The key word to this syllabus point is
EVALUATE
1) Morality
2) Political
3) Religious
Start
11.15

402. The CLONE Wars!!!!
5.20 evaluate the potential for using cloned transgenic animals, for example to produce commercial quantities of human antibodies or organs
for transplantation. (TA)
Advantages
Development of cloned animals which have been genetically engineered to
produce valuable proteins in their milk or blood.
Create identical organisms with exact genetic characteristics required.
Cloning can save animals form extinction.
Disadvantages
Concerns about the ethics of cloning.
Cloning limits variation.
This can effect natural selection.
Concerns about using the technique to clone humans in the future.

404. THE END