AQA GCSE Biology - Paper 1 Exam Study Guide with 100% Correct Answers | Latest Edition

AQA GCSE Biology - Paper 1 Exam Study Guide with 100% Correct Answers | Latest Edition 1. Osmosis practical - ANSWER Weigh identical vegetable pieces and place in varying concentrations of sugar solutions After set time, remove from solution, dry to remove excess liquid, reweigh Calculate change in mass Plot graph At 0% change in mass, the concentrations were equal 2. Organization of human systems - ANSWER Cell, tissue, organ, organ system 3. DS: Mouth - ANSWER Teeth break down food mechanically Saliva contains amylase 4. DS: Stomach - ANSWER Churns food together with hydrochloric acid and enzymes 5. DS: Liver - ANSWER Produces blue- stored in gall bladder before going to small intestine Bile emulsifies lipids into small droplets, increasing surface area for better digestion 6. DS: Pancreas - ANSWER Secretes amylase which breaks down starch into glucose in the small intestine 7. DS: Small intestine - ANSWER Nutrients absorbed by villi However starch is too large 8. DS: Large intestine - ANSWER Water absorbed 9. Enzymes - ANSWER Special proteins that act as biological catalysts, breaking down molecules into shorter ones (polymers to monomers) Specific- only breaking down molecules that fit its active site (lock and key model) 10. Enzyme Denaturation - ANSWER Temperature increases enzyme activity until denature (when the active site changes shape) Same is true for pH Optimum= the condition for maximum activity 11. Digestive enzymes - ANSWER Carbohydrates break down carbohydrates into simple sugars Proteases break down proteins into amino acids Lipases break down lipids into glycerol and fatty acids 12. Enzyme practical - ANSWER Mix amylase and starch, start timer Every ten seconds, add drop to iodine-filled spotting tray Record time taken for no starch to be detected, shown by no colour change in the iodine Repeat at different temperatures or pHs 13. Food tests - ANSWER Starch- iodine turns black Sugar- Benedict's solution goes from blue to brick red Protein- Biuret's reagent goes from blue to purple Lipids: cold ethanol goes cloudy or Sudan III splits into 2 layers, with the top being brick red 14. Lung components - ANSWER Trachea: wind pipe Bronchi: split off pipes Bronchioles: branches Alveoli: air sacs 15. Microscopes - ANSWER Light microscope: cheap, can see cell outline Electron microscope: finer details including organelles due to greater resolving power and higher definition 16. micrometer - ANSWER 'μm' Equal to 1x10^-6 meters Or 1000th (1x10^-3) of a mm 17. Animal and plant cell organelles - ANSWER Cell membrane- semi permeable: controls what enters and exits Nucleus- DNA Mitochondria- respiration Ribosomes- protein synthesis Cytoplasm 18. Only plant cell organelles - ANSWER Chloroplasts- hold chlorophyll for photosynthesis Cell wall- cellulose for rigidity Permanent vacuole- holds sap 19. Prokaryote cells - ANSWER DNA is loose in cytoplasm 20. Mitosis - ANSWER 1. Genetic material duplicates 2. Nuclear membrane dissolves 3. Two sets of chromosomes line up at centre of cell 4. Sets pulled to either side of cell 5. New nuclei forms 6. Other organelles duplicate and cell divides 7. 2 identical diploid cells 21. Specialization - ANSWER Stem cells can specialize to perform specific functions 22. Stem cells - ANSWER Found in embryos and meristems (also in bone marrow, but those can only specialise into blood cells- so can be used for diabetes treatment) Can be used in GM crops or to preserve a species 23. Embryo Clones - ANSWER Make clone of an embryo of a person, extract stem cells Done so they won't be rejected