CCHY 2017 Bio Yearly TYS ANS

6093 Biology Yearly TYS 2017 No Paper 1 Marks Remarks 1 C 1 2 A 1 3 A 1 4 D 1 5 B 1 6 D 1 7 C 1 8 B 1 9 B 1 10 C 1 11 A 1 12 A 1 13 C 1 14 B 1 15 C 1 16 A 1 17 C 1 18 B 1 19 A 1 20 A 1 21 D 1 22 D 1 23 B 1 24 C 1 25 A 1 26 A 1 27 B 1 28 A 1 29 B 1 30 D 1 31 B 1 32 C 1 33 A 1 34 C 1 35 C 1 36 A 1 37 C 1 38 D 1 39 A 1 40 B 1 Total 40

Paper 2 Section A Marks Remarks 1a Homeostasis is the maintenance of a constant internal environment and conditions within the body of an organism + consisting of blood and tissue fluid; Receptors detect stimuli + negative feedback system + reacts to give a reverse effect of a stimulus + restoring the normal condition of the internal environment; 1 1 Definition Describe negative feedback 1b Ductless glands that secrete hormones directly into the blood + transported in the bloodstream to a target organ; e.g. pituitary gland secretes ADH to regulate reabsorption of water at the walls of collecting duct/ adrenal gland secretes adrenaline to increase metabolic rate/ pancreas secretes insulin and glucagon to regulate the BGC 1 1 Definition Example 1ci A: glycogen B: glucagon 1 1 1cii Muscular contractions + increase rate of aerobic respiration + increase demand of glucose; increase glucose uptake into muscle cells + lowering BGC; 1 1 Total 8 2a Keeps the leaf afloat/floating/buoyant on the surface of the water 1 R: did not specify location on water 2b Directly under/nearest to the upper epidermis + to absorb/capture as much sunlight as possible for p/s 1 R: did not take reference to upper epidermis 2c In light -dependent stage, chlorophyll absorbs/traps light energy + convert into chemical energy; Light energy is used to split water molecules into oxygen and hydrogen atoms + photolysis of water; In light-independent stage, hydrogen reduce carbon dioxide to glucose / carbon dioxide gains hydrogen to form glucose 1 1 1 Absorbs light Photolysis

+ using the chemical energy from t he light dependent stage; Reduction of CO2 2d 1 1 R: no plateau at the end of graph R: no highest point to indicate optimum temperature; rate must start and end on zero Total 7 3a photosynthesis + leavs contain chlorophyll that traps and converts light energy into chemical energy + provide energy for other organisms in the food web/ does not get energy from other organisms; 1 3b 74 10 2 1 1 1 3c Pyramid of numbers trophic level 4 trophic level 3 trophic level 2 trophic level 1 title with labelled levels; proportionate to the numbers with appropriate scale; consistent width for all levels; 3 R: incorrect and inconsistent scale Total 7 Percentage of carbon dioxide

4a Measure the initial mass of each plant at the start of experiment (M0) + measure the mass of e