1. Biology 12 Revision 9

2. Nitrogenous wastes Name the nitrogenous waste for each animal and describe the toxicity, solubility, need for energy, need for rapid removal and any advantages for each

3. Nitrogenous wastes Fish produce ammonia Solubility = high Toxicity = high Need for rapid removal = high Need for water = high Need for energy = low Rapidly removed across gills in water Birds produce uric acid Solubility = low Toxicity = low Need for rapid removal = low Need for water = low Need for energy = high Can be easily stored in eggs Allows good survival in places with little water Reptiles produce uric acid Solubility = low Toxicity = low Need for rapid removal = low Need for water = low Need for energy = high Can be easily stored in eggs Allows good survival in places with little water Mammals produce urea Solubility = medium Toxicity = medium Need for rapid removal = medium Need for water = medium Need for energy = medium Can easily cross placenta

4. Temperature regulation 1 Compare temperature regulation between each animal and the elephant.

5. Temperature regulation 1 Ectotherms – not able to control body temperature metabolically Temperature regulation relies on behaviour eg basking, seeking shade Endotherms – can control body temperature metabolically Temperature regulation relies on physiological changes eg sweating, panting, shivering, vasodilation, vasoconstriction as well as behaviour eg basking, seeking shade Small animals have a higher metabolic rate, because they have a larger surface area to volume ratio, and thus lose heat more rapidly They need to eat more per unit volume to maintain this metabolic rate Large animals have a lower metabolic rate, because they have a smaller surface area to volume ratio, and thus lose heat more slowly They need to eat less per unit volume to maintain this metabolic rate Endotherms in cold climates must have adaptations to reduce heat loss eg smaller ears and short fat bodies to reduce surface area, counter current flow in limbs, increased layers of fat, thicker fur or feathers Endotherms in hot climates must have adaptations to increase heat loss eg larger ears and long thin bodies to increase surface area, decreased layers of fat, thinner fur or feathers, more sweating or panting Endotherms living in water will tend to lose heat mainly by conduction and so must have adaptations to reduce heat loss by contact eg short fat bodies to reduced surface area, increased layers of fat Endotherms living on land will tend to lose or gain heat mainly by convection, radiation and evaporation) and so must have adaptations to either increase or reduce heat loss by these methods eg sweating, vasodilation, vasoconstriction

6. Temperature regulation 2 Metabolic rate Environmental temperature Body temperature Metabolic rate Body size Environmental temperature Water loss Complete the graphs below Ectotherm and endotherm Endotherm Ectotherm and endotherm

7. Temperature regulation 2 Metabolic rate Environmental temperature Body temperature Metabolic rate Body size Environmental temperature Water loss Ectotherm Endotherm Endotherms Endotherm

8. Osmotic regulation Describe the osmotic challenge faced by each creature and describe how they solve the problems faced

9. Osmotic regulation Marine invertebrates are osmoconformers – they maintain their body salt levels at the same concentration as their surroundings Sharks are osmoconformers – they maintain high concentrations of urea so their osmotic pressure is the same as their surroundings Freshwater fish have a higher salt concentration than their surroundings This means they constantly gain water and lose salts They maintain balance by ingesting salts, not drinking and producing large amounts of dilute urine Saltwater fish have a lower salt concentration than their surroundings This means they constantly lose water and gain salts They maintain balance by secreting salts from gills and kidneys, constantly drinking and producing small amounts of concentrated urine Osmoregulators Osmoconformers

10. Water regulation in plants Describe the adaptations seen in plants from each of these habitats

11. Water regulation in plants Tropical rainforests have high humidity and rainfall Adaptations include Tough water proof leaves Veins take water away from plant Arid regions have low humidity and rainfall and high temperatures Adaptations include Rolled leaves/reduced leaves/succulent leaves Grey/silver foliage Reduced stomata/ stomata underneath leaves Stomata in pits/hairs guard stomata Water storage in leaves/roots/stems Deep roots/broad shallow roots Tough cuticle/epidermis Coastal areas have low humidity and rainfall, high wind and salinity Adaptations include Rolled leaves Grey/silver foliage Reduced stomata/ stomata underneath leaves Succulent leaves Water storage in leaves/roots/stems Resistant to burial Water plants have high water availability and low air availability Adaptations include Large buoyant leaves Extra air spaces Stomata on top of leaves

12. Photosynthesis & water loss Carbon dioxide concentration Temperature Oxygen production Light Environmental temperature Water loss Oxygen production Oxygen production Complete the graphs below XerophyteHydrophyte

13. Photosynthesis & water loss Carbon dioxide concentration Temperature Oxygen production Light Environmental temperature Water loss Oxygen production Oxygen production Xerophyte Hydrophyte

14. Cell membranes Describe the structure of the cell membrane as revealed by electron microscopy and biochemical studies. Explain how substances move through the cell membrane.

15. Cells Describe the structure of the cell membrane as revealed by electron microscopy and biochemical studies. Phospholipids = A – waterproof, flexible layer, that lets in small particles – diffusion & osmosis Proteins = B – provides channels for larger particles (facilitated diffusion), acts as pumps or gates (active transport), acts as receptor sites Carbohydrates = C - acts as receptor sites A B C

16. Diffusion through membranes Membranes are differentially permeable Permeable substances (eg small particles) Impermeable substances (eg large particles) Movement is Energy Move through Can’t move through From areas of high concentration to areas of low concentration Is not needed

17. Facilitated diffusion Allows larger or less permeable substances to cross Involves channel proteins Energy is not needed

18. Osmosis Movement of water This occurs from areas of high water concentration (low concentration of solute) to areas of low water concentration (high concentration of solute)

19. Active transport Movement against a concentration gradient. Energy is needed

20. Ion pumps Involves special proteins that act as pumps Allows cells to maintain ion concentrations that are very different from the external environment Energy is used

21. Endocytosis Movement due to folding of membrane and bringing in the trapped substances Energy is needed Phagocytosis – solid substances trapped Pinocytosis – liquids are trapped

22. Exocytosis Movement due to vacuoles moving to membrane and attaching to release contents Energy needed

23. Energy transfers Energy transfer occurs in all cellular activities. For each of the following processes involving energy transfer, explain how each functions in the cell and give an example. Explain how ATP is involved in each example you choose. Aerobic RespirationAnaerobic respiration Photosynthesis

24. Anaerobic respiration Occurs in the cytoplasm Does not need oxygen Involves 2 processes – glycolysis and fermentation Glycolysis Glucose is broken down into 2 pyruvate (pyruvic acid) molecules Reactions use 2 ATP Reactions make 4 ATP Net ATP = 2/glucose molecule In animals Pyruvate is converted to lactic acid In plants and fungi Pyruvate is converted to ethanol and carbon dioxide ATP is the end product - used to capture energy of reactions

25. Aerobic respiration Occurs in the mitochondrion Needs oxygen Involves Transition reaction, Krebs cycle and Electron transport chain Involves many reactions and enzymes Produces 36 ATP Waste products are carbon dioxide and water ATP is the end product - used to capture energy of reactions

26. Photosynthesis Uses light energy to convert inorganic molecules to organic molecules Occurs in the chloroplasts of plant cells and some protists and the cytoplasm of cyanobacteria Occurs as a series of reactions, involving many different enzymes Involves light dependent and light independent reactions (the Light and Dark reactions) ATP is used to transfer energy from the light reactions to the dark reactions Net equation: carbon dioxide + water + solar energy  glucose + oxygen + water

27. Photosynthesis Discuss the effect of each of the following factors on the rate of photosynthesis in a living plant: carbon dioxide light intensity temperaturewater conservation

28. Photosynthesis Discuss the effect of each of the following factors on the rate of photosynthesis in a living plant: carbon dioxide light intensity temperaturewater conservation As stoma close to reduce water loss, carbon dioxide levels fall and photosynthesis decreases