GCSE IGCSE Biology by Syllabus points

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

18. 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

19. 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.

20. 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

21. 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

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 Some pretty pictures of bacteria

23. 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

24. 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

25. 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

26. 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

27. 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

28. 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

29. 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

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 You just have to recognize a virus, but there are several shapes

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 REVIEW FROM YEAR 8

32. 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

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 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

34. Just thought you would like to know.

35. 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

36. 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.

37. 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

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

39. 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

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

41. 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.

42. 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

43. 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

44. 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

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

46. 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.

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 CARBOHYDRATE BONDS ARE CALLED: Glycosidic Bonds

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 BONDS IN PROTEINS ARE CALLED: Peptide 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 FATTY ACIDS AND GLYCEROL ARE CALLED: Ester Bond

50. 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

51. 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

52. 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

53. 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.

54. 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

55. 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

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 • They occur inside cells or are secreted by the cells. • Catalase is the enzyme that catalyses the break down of hydrogen peroxide. Catalase

57. 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

58. 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.

59. 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.

60. 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?

61. 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

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 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.

63. 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.

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) 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

65. 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

66. 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.

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 seed germination starch embryo plant amylase secreted maltose

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

69. 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.

70. 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

71. 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

72. 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

73. 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.

74. 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)

75. 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.

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

77. 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)

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 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.

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 WHAT IS THE SURFACE TO VOLUME RATIO’S FOR THESE TWO CELLS?

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 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:

81. 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.

82. NUTRITION (Yum Yum Yum)

83. 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.

84. 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)

85. 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

86. 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

87. 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.

88. 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?

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

90. ?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.

91. 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.

92. 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.

93. 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

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

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

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

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

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

99. 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

100. 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

101. Experiment we CAN NOT do!

102. 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

103. 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

104. 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

105. 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

106. 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).

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 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?

108. 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…

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 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.

110. Nutrition in Humans Syllabus points 2.23 – 2.32

111. 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.

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)

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) 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)

114. 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

115. 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

116. 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?

117. 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.

118. 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

119. 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

120. 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

121. 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

122. 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

123. 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

124. 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.

125. 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.

126. 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)

127. 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?

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

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

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

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

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

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

134. 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!

135. 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

136. 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)

137. 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)

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

139. 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

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

141. 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.

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

143. 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

144. Gas Exchange in Humans Syllabus points 2.44 – 2.48

148. Transport syllabus points 2.49 – 2.50

149. Transport syllabus points 2.49 – 2.50

150. 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. Transport in Humans (2.57 – 2.66)

164. 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

165. 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

166. 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.

167. 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

168. 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)

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

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

171. 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

172. 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

173. 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)

174. 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.

175. 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

176. 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.)

177. 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)

178. 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

179. 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.

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

181. 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.

182. 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.

183. 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.

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

185. 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

186. 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

187. 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.

188. 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)

189. 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

190. 2.81 describe the geotropic responses of roots and stems

191. 2.81 describe the geotropic responses of roots and stems You do need to know some fun experiments with plants

192. 2.81 describe the geotropic responses of roots and stems What happens when you grow a plant in space?

193. 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?)

194. 2.82 describe positive phototropism of stems

195. MORE EXPERIMENTS 2.82 describe positive phototropism of stems

196. 2.82 describe positive phototropism of stems What if you grow a plant in the dark?

197. 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.

198. 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)

199. 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

200. 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

201. 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.

202. 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

203. 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

204. 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).

205. 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

206. THE EYE

207. 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

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

209. 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

210. 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’

211. 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

212. 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

213. 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

214. 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

215. 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)

216. 2.89 describe the role of the skin in temperature regulation, with reference to sweating, vasoconstriction and vasodilation (TA)

217. 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

218. 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

219. 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).

220. 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.

221. Reproduction in Plants (3.3 - 3.7)

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

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

227. 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

228. 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.

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

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

231. 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

232. 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

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

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

235. INHERITANCE (Syllabus points 3.13 – 3.33)

236. 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).

237. 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.

238. 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

239. 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

240. 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)

241. 3.13 understand that the nucleus of a cell contains chromosomes on which genes are located

242. 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

243. 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

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 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.

245. 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

246. 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.

247. 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

248. 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)

249. 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

250. 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………..

251. 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

252. 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

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

255. 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

257. 3.17 understand the meaning of the terms: dominant, recessive, homozygous, heterozygous, phenotype, genotype and co-dominance

258. 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

259. CODOMINANCE

260. 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.

261. 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

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

263. 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

264. 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

265. 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

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

267. 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

268. 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

269. 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

270. 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

271. 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”

GCSE IGCSE Biology by Syllabus points

Marc Rodriguez

GCSE IGCSE Biology by Syllabus points