1. B2 Exam Revision

2. Plant cells vs. Animal cells Both types of cell have these: Only plant cells have these: Nucleus This controls the cell Cytoplasm This is the jelly like substance where chemical reaction take place Cell wall Gives support to the cell Large vacuole Large space filled with cell sap Cell membrane Controls what goes in and out of the cell 1) 2) 3) 6) 5) 7) Mitochondria Energy is released here by respiration 4) Chloroplasts Where photosynthesis takes place

3. Complete this definition of Diffusion using the key words: Diffusion is the _______ __________ of ______ from where there are lots of particles ( high __________) to where there are less particles. We say the particles diffuse down a concentration _________. In cells, the cell membrane has small holes that allow small particles through, but not large molecules. We call this membrane ________ ________. The bigger the difference in concentration, the faster the rate of ________. Partially permeable Diffusion Concentration Gradient Random movement Particles

4. Photosynthesis - The equation 1. What factors are needed to make glucose? 2. What products are made by photosynthesis?

5. Limiting factors If you alter the levels of light, carbon dioxide or change the temperature the rate of photosynthesis will change!

6. What happens to the glucose?

7. Enzymes Enzymes are biological catalysts, they increase the rate of reactions. Enzymes are protein molecules made up of long chains of amino acids. When enzymes are denatured the active site changes shape.

8. What happens at the active site? In the same way that a key fits into a lock, so a substrate is thought to fit into an enzyme’s active site. The enzyme is the lock, and the reactant is the key. + ↔↔ + enzyme reactant + enzyme-reactant complex ↔ products enzyme + ↔

9. Factors affecting enzymes If the temperature and pH changes sufficiently beyond an enzyme’s optimum, the shape of the enzyme irreversibly changes. normal denatured heat pH This affects the shape of the active site and means that the enzyme will no longer work. When this happens the enzyme is denatured.

10. Aerobic Respiration Oxygen + Glucose Carbon Dioxide + Water Energy + +

11. Amylase Protease Lipase Bile Hydrochloric acid Where are the enzymes found?

12. Enzymes of digestion

13. Chromosomes, Genes and Alleles 1. ………….. 2. ………....... 3. …………….. 4. ……………… B b 5. ……………. Nucleus, Gene, Chromosome, Allele, Cell (b)

15. How is meiosis different???

16. Why was his work not spread quickly? He was not a famous scientist – nobody knew about him at the time. His job as abbot stopped him giving lectures at universities. He published his work in an obscure journal that few people read. Biologists at the time did not think mathematics had anything to do with Biology. Gregor Mendel (The Pea Plant Man)

17. Disease Some disorders are inherited Huntington’s disease is caused by a dominant allele of a gene and can be inherited from only one parent Cystic fibrosis is caused by a recessive allele of a gene and so must be inherited from both parents

18. Cystic Fibrosis The treatment involves chest physiotherapy. They are very prone to chest infections and malnutrition. The mucus encourages the growth of pathogenic microbes that cause infection and cause long term lung damage.