The document describes the different levels of organization within organisms, from organelles to cells to tissues to organs to organ systems. It provides examples of structures at each level such as organelles including the nucleus, chloroplasts and mitochondria. Cells include skin cells, muscle cells and neurons. Tissues include muscle, nerves and blood. Organs include the heart, skin and brain. Organ systems include the circulatory, nervous and endocrine systems.

1. 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

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

3. 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

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

5. 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.

6. 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

7. 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

8. 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

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

10. 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.

11. 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

12. 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

13. 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

14. 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

15. 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

16. 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

17. 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.

18. 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

19. 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

20. 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

21. 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

22. 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.

23. 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.

24. 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?

25. 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

26. 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.

27. 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.

28. 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

29. 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

30. 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.

31. 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

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

33. 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.

34. 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

35. 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

36. 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

37. 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.

38. 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)

39. 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.

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

41. 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)

42. 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.

43. 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?

44. 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:

45. 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.