CCHY 2013 Bio Yearly TYS ANS

6093 Biology Yearly TYS 2013 No Paper 1 Marks Remarks 1 B 1 2 C 1 3 C 1 4 D 1 5 D 1 6 A 1 7 D 1 8 C 1 9 D 1 10 C 1 11 C 1 12 D 1 13 A 1 14 A 1 15 D 1 16 B 1 17 C 1 18 C 1 19 B 1 20 D 1 21 D 1 22 B 1 23 A 1 24 C 1 25 B 1 26 B 1 27 B 1 28 A 1 29 B 1 30 B 1 31 B 1 32 B 1 33 D 1 34 C 1 35 C 1 36 B 1 37 B 1 38 A 1 change option A to 23 + 1X for chromosomes in ovum 39 B 1 40 A 1 Total 40

Paper 2 Section A 1ai P: right atrium Q: bicuspid valve/ chordae tendineae 1 1 1aii Line drawn pointing to aorta with label X 1 1b Oxygenated blood from lungs flows into LA through pulmonary veins; muscles of LA contract increasing P(LA)+ When P(LA) is higher than P(LV), bicuspid valves open allowing blood to flow from LA to LV; muscles of LV contract increasing P(LV)+ when P(LV) is higher that P(LA) bicuspid valves closes to prevent backflow of blood into LA; When P(LV) is higher than P(aorta), semilunar valves open to force out of LV into aorta at high pressure , transported to all parts of the body; When P(aorta) is higher in P(LV), semilunar valves closes to prevent backflow of blood into LV; 1 1 1 1 Entry of blood into heart Atrial contraction Ventricular systole Closure of valves R: atrium contract A: muscles of the atrium contracts 1ci P(LV) = Line 2 P(LA) = Line 3 P(aorta) = Line 1 P(LV) > P(LA) = 0.1 P(LV) < P(aorta) = 0.4 0.4 – 0.1 = 0.3s 1 1cii Line 2 1 Total 9

2a Translocation is the transport of m anufactured food substances such as sucrose and amino acids by active transport; Occurs through the phloem from the leaves to the other parts of the plants vice versa/ bi-directional; 1 1 substances process location direction 2bi Left side beside the cambium nearer to pith 1 2bii Right side, darker region nearer to epidermis 1 2c Weed killers are soluble in water / dissolves in water in soil; weed killer diffuse into the root hair cells down concentration gradient + diffuse from RHC into t he adjacent root cells down concentration gradient until the xylem; weed killers move u p the xylem vessel in the stem by transpiration pull; Weed killer reaches the x ylem vessel in the leaf veins + reaching the chloroplasts in the mesophyll cells in the leaf; 1 1 1 1 solubility soil to RHC to RC to xylem process xylem to leaf to MC Total 8

3a P: branch of renal artery 1 3bi Protein content: 0.0 Glucose content: 0.1 1 1 3bii Proteins are present in P but not in R + at glomerulus, proteins are retained in the glomerular capillaries; they are too large to pass through the walls of the glomerular capillaries and the partially permeable basement membrane + no proteins in R; 1 1 3biii Absence of glucose in R + at PCT, most glucose are selectively reabsorbed through the