Name:. ( ) U6S.. SMJK 964 PEREMPUAN CHINA PULAU PINANG SMJK PEREMPUAN School CHINA Level PULAU Test PINANG

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1 Name:. ( ) U6S.. SMJK 964 PEREMPUAN CHINA PULAU PINANG SMJK PEREMPUAN School CHINA Level PULAU Test PINANG SMJK PEREMPUAN CHINA PULAU BIOLOGY PINANG SMJK PEREMPUAN CHINA PULAU PINANG Suggested Mark Schemes SMJK PEREMPUAN CHINA PULAU PINANG 90 minutes SMJK PEREMPUAN CHINA PULAU PINANG Part A Structure Questions 30 MARKS Write the answers or correct solutions in the answering space after each question. Question 1: (a) The table shows some of the characteristics of two types of plant cell. [8 MARKS] (i) Identify cells X and Y. [1] X = tracheid Y= vessel (Both gain 1 mark, either one wrong then no mark) (ii) Suggest why flowering plants possess large amount of tissue formed from cell Y rather than from cell X. [1] large leaf surface area and many stomata results in much water loss by transpiration o this must be replaced from transpiration stream/pull vessels can transport greater volumes/faster than tracheids (Either one) (iii) Name the tissue in flowering plants where sugars and amino acids are transported. [1] Phloem / sieve tube Page 1

2 (iv) Name the two main types of cell found in that tissue. [1] sieve tube & companion cell (v) What is meant by the term mass flow? [1] the bulk transport of materials from one point to another; as a result of pressure difference between the two points (source to sink) (b) The diagram below illustrates the mass flow hypothesis. This hypothesis has been suggested to explain transport through the phloem. (d) Name the main carbohydrate transported in the phloem. [1] Sucrose (e) Use information from the illustration to explain how the high hydrostatic pressure is produced at A. [2] higher concentration of solute/named solute inside sieve tube / phloem causing lower water potential water moves from a high to a low water potential / down a water potential gradient by osmosis / diffusion Page 2

3 Question 2: [5 marks] The graph shows changes in pressure in the aorta, left ventricle and left atrium during one heart beat of Sue Ching. (a) The maximum pressure in the left atrium is lower than the maximum pressure in the left ventricle. What causes this difference in maximum pressure? [1] less muscle / thin(ner) wall in left atrium (b) A stethoscope can be used to listen to the sounds made by the heart. (i) What is the evidence from the graph that the first heart sound is caused by the atrioventricular valve closing? [1] pressure of left ventricle higher than pressure of left atrium (ii) What causes the second heart sound? Give the reason for your answer. [1] closing of the semi-lunar valves / pocket valves pressure in artery / aorta is higher than ventricle (c) Our heart rate increases during exercise. Describe the ROLE played by the chemoreceptors and the medulla oblongata in increasing the heart rate. [2] (i) chemoreceptors (located in) carotid / aortic bodies / medulla detect high carbon dioxide levels / H + / low ph due to increased respiration Page 3

4 (ii) medulla oblongata more impulses (from medulla) to SA node via sympathetic nervous system (accept converse reference to parasympathetic) (send nervous) impulse to medulla oblongata / respiratory centre Question 3: [8 marks] (a) Muscle cells contain large numbers of mitochondria that supply the ATP for muscle contraction. The ATP is produced by oxidative phosphorylation. Use the most appropriate word or words to complete the paragraph below on oxidative phosphorylation. [2] Hydrogen atoms from the Krebs cycle are brought to the electron transport chain reduced carried as NAD or FAD. Here the hydrogen atoms are split into protons and electrons. The electrons flow through carriers and during this process energy / proton is transferred. The protons are pumped across the inner membrane, producing a electrochemical gradient. As the protons flood back through the stalked particles, the enzyme.. ATP synthetase forms ATP from ADP and inorganic phosphate. (b) Fatty acids and cholesterol are synthesised in the liver from acetyl coenzyme A (acetyl CoA). One way in which acetyl CoA is generated is from pyruvate, which enters mitochondria during aerobic respiration of glucose. Acetyl CoA can enter the Krebs cycle, if ATP levels within the cell are low, or enter alternate pathways to synthesise fatty acids or cholesterol. The diagram below illustrates these pathways schematically. Page 4

5 (i) State the progress taking place in the cytoplasm which produces pyruvate from glucose. [1] Glycolysis (ii) Describe how triglycerides are formed in the liver from fatty acids. [1] Glycerol + three fatty acids (condensation reaction formation of ester bond) (iii) Name the organelles where triglycerides are formed. [1]... Smooth endoplasmic reticulum / smooth ER (iv) Fats are an important respiratory substrate for mammals. Describe how stored fats may be used to generate ATP when a mammal is starving. [3] (triglycerides are) hydrolysed / broken down, to fatty acids β-oxidation / to form 2 carbon fragments to form acetyl CoA, enters Krebs cycle during aerobic respiration glycerol enters glycolysis, then enters, link reaction / Krebs cycle and ETC Question 4: [4 marks] A student named Sarah investigated the effect of red and green light on the rate of photosynthesis. She placed Spirogyra on a microscope slide. Then she mounted the slide in water which contained many bacteria. Her friend, Aeon, shone spots of red and green light on to different parts of the Spirogyra. The rest of the Spirogyra was in the dark. The results are shown in the diagram below. (a) Explain the difference in the numbers of bacteria in the red and green light spots. [2] Red light leads to more photosynthesis/more oxygen produced (than green light) (More of) red light absorbed (by chlorophyll) / (Most) green light reflected The bacteria moved to areas where the oxygen concentration was highest. Bacteria need oxygen to respire. (b) Distinguish between cyclic and non-cyclic photophosphorylation. [2] Cyclic photophosphorylation Non-cyclic photophosphorylation the process in which electrons are emitted from PSI the process in which electrons are emitted from PSII pass through carriers with the electrons pass through carriers production of ATP pass to PSI with the production of ATP and back to PSI loss of electrons from PSII stimulates photolysis produces ATP, oxygen & NADPH Page 5

6 Question 5: The diagram below shows a section through the stomach wall. [5 marks] P (a) Name the layers A to D. [2] Mucosa A Muscle layer / smooth muscle / C longitudinal AND circular muscle / muscularis externa Submucosa B Serosa / connective tissue D (b) Cells in the lining of the stomach secrete pepsinogen, an inactive form of the enzyme pepsin. Indicate in the diagram above, using a label line marked with the letter P, a cell that secretes pepsinogen. [1] P pointing to peptic / chief cells in gastric gland (c) Explain why cells in the stomach secrete pepsinogen rather than pepsin. [2] (inactive enzyme) prevents autodigestion only converted to pepsin when food is present OR only converted when, HCl / acid, is present in the stomach Page 6

7 Part B Multiple Choice Questions Write the answers for each question in the answer box in the last page. 1. The diagram below shows the biochemical process of glucose degradation occuring in a cell. What do X, Y and Z represent? X Y Z A. Acetyl coenzyme A Ethanol Lactate B. * Fructose-1,6- biphosphate Dihydroxyacetone phosphate Glyceraldehyde -3- phosphate C. Malate Pyruvate Ethanol D. Pyruvate Lactate Acetyl coenzyme A 2. The Bohr s effect is very important to actively respiring cells because A. high carbon dioxide concentration causes faster release of oxygen. * B. large quantity of ATP is required to facilitate the diffusion of gases. C. high rate of glucose oxidation stimulates the secretion of insulin. D. low oxygen concentration stimulates the increase in the rate of breathing. 3. Which are true of the sinoatrial node? I It is situated at the posterior wall of the right atrium. II It acts as the pacemaker. III It can start the contraction of the atrium and ventricle almost simultaneously. IV It causes the contraction of the left and right ventricles almost simultaneously. A. I and II * C. II and III B. I and IV D. III and IV 4. The diagram below shows a chloroplast. 5. The lowering of ph of human blood causes A. the rate of heart beat to decrease B. the rate of heart beat to increase * C. less oxygen to be released from oxyhaemoglobin D. less carbon dioxide to be bound with haemoglobin What are the structures X and Y and their functions? X Function of X Y Function of Y A. Granum CO 2 fixation Lamella Photolysis of water B. Granum Photolysis of Stroma CO 2 fixation * water C. Stroma Photolysis of Granum CO 2 fixation water D. Lamella CO 2 fixation Granum Photolysis of water Page 7

8 6. The light reactions drive the redox process that involves the following pairs of reactants/products A. H2O/O2 and FAD/FADH2 B. H2O/O2 and NADH/NAD + C. O2/H2O and NADPH/NADP + D. H2O/O2 and NADP + /NADPH * 7. Fermentation A. is restricted to yeasts. B. breaks down glucose in reaction with oxygen. C. may occur in a muscle under anaerobic conditions. * D. produces more ATP than is liberated in the hydrogen transfer series. 8. Three of the four answers listed below are molecules that donate hydrogens to NAD +. Select the exception. A. Succinate * C. Isocitrate B. Alpha-ketoglutarate D. pyruvate 9. Which of the following have osmoreceptors to detect changes in osmotic pressure in the blood? I Aorta II Carotid sinus III Hypothalamus A. I and II C. II and III * B. I and III D. I, II and III 10. Which of the following is the special characteristic of CAM plants as compared to C4 plants during photosynthesis? A. Low rate of photorespiration B. The presence of Krantz anatomy C. The production of malate at night * D. Effective fixation of carbon at high temperatures 11. Three of the four answers listed below are processes associated with light-dependent reactions. Select the exception. A. photolysis B. chemiosmosis C. fixing carbon dioxide * D. noncyclic pathways of ATP formation 12. Which of the following is/are true of chemosynthetic bacteria? I They are autotrophic. II They get the energy from sunlight. III They oxidise inorganic compounds to obtain energy. A. I only C. II and III B. I and III * D. I, II and III 13. The main function of a stoma is to A. respond to the environmental stress B. allow the diffusion of gas into the mesophyll cell C. regulate the movement of water during transpiration D. allow the diffusion of gas while regulating water loss * 14. The diagram below shows non-cyclic photophosphorylation during the light reaction of photosynthesis. Page 8

9 Which of the following is true of X, Y and Z? X Y Z A. Ferredoxin Plastoquinone Plastocyanin B. Ferredoxin Plastocyanin Plastoquinone C. Plastocyanin Plastoquinone Ferredoxin D. Plastoquinone Plastocyanin Ferredoxin * 15. The heart A. will contract as a result of stimuli from the sinoatrial node. * B. contracts only as a result of nerve stimulation from the central nervous system. C. is activated primarily through the autonomic nervous system. D. pulse is primarily under the control of the atrioventricular node. 16. The events which lead to the opening of a stoma are as follows: I The stoma is open. II The guard cells become turgid. III The water potential of the guard cells decreases. IV Water enters the guard cells osmotically. V Potassium ions are actively transported into the guard cells. Which sequence of events is correct? A. III, IV, V, II, I B. III, V, IV, II, I C. V, III, IV, II, I * D. V, IV, III, II, I 17. An example of saprophytic organism is A. Rafflesia sp. B. Taenia sp. C. Mucor sp. * D. Periplenata sp. 18. The diagram below shows the diffusion of carbon dioxide from respiring cells into the blood involving steps P, Q, R and S. Page 9

10 Which step requires carbonic anhydrase to proceed to the next? A. P * B. Q C. R D. S 19. The oxygen dissociation curve for the haemoglobin of an individual is further left compared to the oxygen dissociation curve for the haemoglobin of a normal individual. Which statements are true of that individual? I The individual migrates from a low altitude to a high altitude. II The individual migrates from a high altitude to a low altitude. III The total haemoglobin and red blood cell count of the individual increases. IV The total haemoglobin and red blood cell count of the individual decreases. A. I and III * B. I and IV C. II and III D. II and IV 20. The following table shows the reactions of photosynthesis and their facts. Reaction Fact I Calvin cycle P Occurs in the stroma II Light Reaction Q Produces oxygen R Reduces NADP + S Uses ATP Which of the following is correct for the reactions and their facts? P Q R S A. I I II II B. * I II II I C. II I I II D. II II I I ANSWER: 1. B 2. A 3. A 4. B 5. B 6. D 7. C 8. A 9. C 10. C 11. C 12. B 13. D 14. D 15. A 16. C 17. C 18. A 19. A 20. B Page 10

11 Additional (detail) Question 4b (iv) Fats are an important respiratory substrate for mammals. Describe how stored fats may be used to generate ATP when a mammal is starving. [3] (triglycerides are) hydrolysed / broken down, to fatty acids (stored in) adipose tissue lipolysis / refer to lipase fatty acids are transported in the bloodstream enter the liver are broken down / catabolised into fatty acyl CoA in cytoplasm (of hepatocytes) fatty acyl CoA enters mitochondrion β-oxidation / to form 2 carbon fragments to form acetyl CoA (acetyl CoA) enters Krebs cycle during aerobic respiration liver may form, ketone bodies / acetoacetate / β-hydroxybutyrate exported out of the cell/ enter circulation for other tissues to use as a respiratory substrate glycerol enters glycolysis (part-way) then enters, link reaction / Krebs cycle and the ETC energy dense / described highly reduced state of, lipids / fatty acids one complete turn of Krebs for each 2C fragment from fatty acid e.g. bound to albumin, fate of acetoacetate in tissues Prepared by Yeap Chee Beng Page 11

AP Bio Photosynthesis & Respiration

AP Bio Photosynthesis & Respiration Multiple Choice Identify the letter of the choice that best completes the statement or answers the question. 1. What is the term used for the metabolic pathway in which