2022 Pure Biology TYS Answers

2022 6093/1 Answers Qn Answers Qn Answers 1 D 21 B 2 B 22 B 3 D 23 A 4 B 24 C 5 C 25 D 6 B 26 B 7 C 27 D 8 D 28 D 9 A 29 B 10 D 30 A 11 B 31 B 12 B 32 B 13 C 33 D 14 D 34 C 15 D 35 C 16 D 36 A 17 A 37 D 18 C 38 B 19 A 39 A 20 D 40 A

2022 6093/2 Answers Section A Qn Answers Remarks 1a No nucleus + more space to carry haemoglobin to bind to oxygen; Biconcave shape + increase surface area to volume ratio + faster rate of diffusion of oxygen + in and out of the cell; Candidates should link structure to its correct function. Students should state that haemoglobin bind to oxygen instead of transport oxygen. RBCs are also biconcave and not concave. Candidates should link lack of nucleus to providing more room for haemoglobin instead of just oxygen. 1bi Decreased oxygen at cells or muscles + reduced ability to carry out aerobic respiration + less energy released at muscles for walking up stairs; Heart rate and breathing rate increase to get more oxygen and deliver oxygen to muscle cells; Anaerobic respiration + release more energy required; Produce lactic acid + build-up of lactic acid + muscle fatigue; Candidates should describe how breathing or heart rate would be affected and/or describe tiredness. Less oxygen would be delivered to the muscles or cells for aerobic respiration. Response should also include the need for anaerobic respiration. Candidates should note that responses should be specific including stating the type of respiration e.g aerobic respiration instead of generalised description of less oxygen delivered to the ‘body’, or just referred to ‘respiration’ without specifying aerobic respiration. Cellular respiration is unclear if it refers to aerobic or anaerobic respiration. ii Pulmonary vein; Oxygen diffuse from alveolus to red blood cells + blood vessel from lungs + highest concentration of oxygen; Candidates should take note, not to mistake pulmonary vein for pulmonary artery. Answers should be succinct with clear points to justify

their choice. 1c Transported to lungs + gaseous exchange + excretion of carbon dioxide as waste product + during exhalation; White blood cells Good answers for the reasons of transport of carbon dioxide should include the lungs, excretion, or exhalation. 2ai Palisade mesophyll cell Candidate should clearly state the type of cell instead of just leaf cell which had been mentioned in the question 2aii Large central vacuole 2aiii mitochondrion/ribosome Nucleus not acceptable as it is shown in the diagram 2b Chloroplast would move towards light source + in the cell Light energy is required for photosynthesis + absorb by chlorophyll; Nearer the light source for maximum amount of light energy + convert light energy to chemical energy Answers should show understanding of the need for light energy to be absorbed by chlorophyll for photosynthesis. Chloroplast would not migrate to the top of the leaf or epidermis but only within the cell, and would spread out so as not to overlap with each up. 2c Water molecules + osmosis and Carbon dioxide + diffusion; Water molecules down a water potential gradient + carbon dioxide down a concentration gradient; Through the cell wall and cell membrane; Answers should include how water molecules travelled from cell to cell by osmosis and that carbon dioxide moved by diffusion, and that movement was always ‘down a concentration gradient’. Both water and carbon dioxide would need to cross the cell surface membrane and the cell wall. Candidates who described movement of water from its

uptake in the roots, up the xylem to the leaf did not note the requirement of the question. 3a Long; Pendulous; Candidates should not give two correct answers in the first space and give further information in the second. Candidates should be careful not to give stigma features to stamens. 3bi Carbon, oxygen and hydrogen Nitrogen is not acceptable as it is not found in carbohydrates and fats 3bii White flour has a more digestible carbohydrates at 80.1g and 76.3g than brown flour at 76.5g and 72.0g in 100g of flour; White flour has less indigestible carbohydrates than brown flour such as 2.4g as compared to 4.6g for rice flour and 2.7g as compared to 10.7g for wheat flour; White flour has lesser protein than brown flour such as 5.9g as compared to 7.2g for rice flour and 10.3g as compared to 13.2g for wheat flour; White flour has lesser fats than brown flour such as 1.4g as compared to 2.8g for rice flour and 1.0g as compared to 2.5g for wheat flour; Candidates should clearly state the difference between named types of flour, instead relying on lists of quoted figures only. Comparative terms such as ‘less’ or ‘more’ should complement the use of figures to give others a better understanding of differences. 3biii Dissolve a spatula of flour in 2cm 3 of water in a test tube. Add 2cm 3 of biuret solution and shake to mix. Observe colour change. If biuret solution changes from blue to violet solution, protein is present. If the biuret solution remains blue, protein is absent. The test and expected colou r for protein should be described.

3c Rate of absorption of nutrients such as glucose, amino acids, fatty acids and glycerol would be reduced + the surface area to volume ratio of the surface of absorption is reduced; Lesser glucose absorption of glucose and amino acids through blood stream + fatty acids and glycerol through lacteals; Nutrients would be lost and egested without absorption; Candidates should state that absorption would be reduced as the surface area for absorption was reduced. Stronger responses should include further detail, such as stating specific nutrients that would be absorbed (into the bloodstream or lacteals) or egested without absorption. 4ai Candidates should note that blood in the hepatic portal vein flowing towards the liver 4aii Hepatic vein 4bi Fair comparison due to differences in population sizes, total number of cases might not be an accurate representation of the proportion of people with liver disease in the two areas Candidates should focus on identifying that the population sizes could be different. 4bii Number of cases in A is much higher than cases inB + in the first 40 year in A, cases increase from 38 cases per 100 000 in 1960 to 64 cases per 100 000 in 1980 whereas in B, cases increases from 6 cases per 100 000 men in 1960 to 14 cases per 100 000 in 1980; From 1980 to 2000, number of cases in A start to decrease to 38 cases per 100 000 + number of cases in B continue to increase to 27 cases per 100 000 Comparisons should be supported with data including the figures ‘per 100 000’ and not attempt to manipulate the figures (e.g. 500 000 cases in B in 1960). 4biii People are more aware about dangers of alcohol consump