NCHS_Bio_P2ans

2021 Prelim Bio P2 MS 1a P: ovary; Q: cervix; R: vagina 3 correct – [2]; 2 correct – [1]; 1 correct – [0] 1b The oviduct is blocked/ occluded/ sealed/ closed off [1] Fertilisation cannot occur as ovum cannot be moved to meet/ fuse with the sperm due to the blocked oviduct. [1] 1c X is in uterine lining [1] 1d Between day 21-24; [1] Progesterone functions to maintain the thickness of the uterine lining; [1] During this period, progesterone level is increasing towards peak, indicating uterine lining is most likely the thickest. [1] 2a ANY one of below Epithelium of the villus have numerous microvilli; [1] to increase surface area to volume ratio for faster absorption of digested food [1]. OR Epithelium/ wall of villus is one cell thick [1] to reduce diffusion distance for faster absorption of digested food [1]. OR Contains a lacteal which continually transports fats away from ileum [1] to maintain a steep concentration gradient for faster absorption of fats [1]. OR Well-supplied with blood capillaries which continually transports digested food away from duodenum [1] to maintain a steep concentration gradient for faster absorption of digested food [1]. 2b The villi in person with coeliac disease is shorter/ has smaller surface area to volume ratio [1]. Less glucose absorbed into bloodstream, resulting in less aerobic respiration, releasing less energy, hence causing fatigue [1] 3a correct arrangement of at least 4 vascular bundles [1] correct labelling of xylem and phloem [1]

3b When the rate of respiration slows down, less energy is released resulting in less active transport [1]. Less active transport results in less translocation of sucrose and amino acids from leaves to the rest of the plant for growth [1]. Less respiration results in less energy for cell activities such as photosynthesis to produce glucose, reducing plant growth [1]. Less mineral ions absorbed/ ions absorbed more slowly at the roots by active transport [1]. Less nitrate ions causes less amino acids / protein results in less protoplasm/ growth; [1]  3ci Loss of water vapor through stomata of leaves [1] 3cii The wind blows away the water vapour that accumulates outside the leaf. [1] This causes a steeper water vapour concentration gradient between the inside of the leaf and the atmosphere. [1] This allows water vapour to diffuse out of the leaf faster [1], increasing rate of transpiration. 3ciii The leaf folds up, reducing exposed surface area to reduce rate of transpiration OR stomata closes, reducing rate of transpiration. [1] 4a 8 [1] 4b Only visible features were accepted as this question ask for ‘this flower’. Any [2] Has a large and conspicuous petal; [1] Non-pendulous anther and compact stamen; [1] Non-feathery and compact stigma; [1] 4ci self-pollination [1] 4cii Any [2] · Plants bear either male or female flowers. · Anthers and stigmas in the same plant mature