Unit 1C Practice Exam (v.2: KEY)

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1 Unit 1C Practice Exam (v.2: KEY) 1. Which of the following statements concerning photosynthetic pigments (chlorophylls a and b, carotenes, and xanthophylls) is correct? (PT1-12) a. The R f values obtained from a chromatographic analysis are the same for these molecules. b. The wavelength of light absorbed is the same for these molecules. c. The molecules have the same molecular weight. d. The molecules have the same affinity to cellulose e. The molecules absorb energy by boosting electrons to higher energy orbitals 2. When ATP is produced in the mitochondria, all of the following occur EXCEPT. (PT1-23) a. Water is formed from O 2, electrons, and H + b. NADH is converted to NAD + + H + c. Protons are pumped out of the mitochondria d. An electrochemical gradient is established across mitochondrial membranes e. A ph gradient is established across mitochondrial membranes 3. In C 3 plants, the enzyme that incorporates CO 2 into an organic molecule is. (PT1-49) a. Helicase b. PEP carboxylase c. RuBP carboxylase/oxygenase d. Carboxypeptidase e. Pyruvate decarboxylase 4. The products of the Krebs cycle include. (PT1-52) a. ATP, NADH, FADH 2, CO 2 b. ATP, NAD +, FAD, CO 2 c. ATP, H 2O, O 2 d. ADP, CO 2, H 2O e. NADH, FAD+, CO 2 5. Experimental evidence shows that the process of glycolysis is present and virtually identical in organisms from all three domains: Archaea, Bacteria, and Eukarya. Which of the following hypotheses could be best supported by this evidence? ( ) a. All organisms carry out glycolysis in mitochondria b. Glycolysis is a universal energy-releasing process and therefore suggests a common ancestor for all forms of life. c. Across the three domains, all organisms depend solely on the process of anaerobic respiration for ATP production. d. The presence of glycolysis as an energy-releasing process in all organisms suggests that convergent evolution occurred. 1

2 6. The chemical reaction for photosynthesis is: 6 CO H 2O + light energy C 6H 12O O H 2O If the input water is labeled with a radioactive isotope of oxygen, 18 O, then the oxygen gas released as the reaction proceeds is also labeled with 18 O. Which of the following is the most likely explanation? ( ) a. During the light reactions of photosynthesis, water is split, the hydrogen atoms combine with the CO 2, and oxygen gas is released. b. During the light reactions of photosynthesis, water is split, removing electrons and protons, and oxygen gas is released. c. During the Calvin cycle, water is split, regenerating NADPH from NADP +, and oxygen gas is released. d. During the Calvin cycle, water is split, the hydrogen atoms are added to intermediates of sugar synthesis, and oxygen gas is released. Questions 7-8 refer to the following experiment. An experiment was conducted to determine whether light and chloroplasts are necessary for photosynthesis. To detect photosynthesis, DPIP, and electron acceptor, was used. DPIP is blue in its oxidized state but turns clear when reduced. That is, when electrons from photosynthesis are transferred to DPIP, the blue solution (oxidized DPIP) turns clear (reduced DPIP). A spectrophotometer measures the degree to which the blue solution becomes clear. (The clearer the solution, the greater its transmittance.) Assume that the ability of DPIP to accept electrons is not affected by heat. Three groups, each containing four solutions, were tested in the experiment. All solutions contained chloroplasts and DPIP. Four solutions in the first group were each exposed to light for 0, 5, 10, and 15 minutes, respectively. Four solutions in the second group were each kept in darkness for 0, 5, 10, and 15 minutes, respectively. Four solutions in the third group were each boiled before being exposed to light for 0, 5, 10, and 15 minutes, respectively. The graph that follows shows the results of the experiment. 7. Which of the following is correct? (PT1-96) a. It is reasonable to conclude that light absorbance is maximum at 400 nm. b. It is reasonable to conclude that light absorbance is maximum at 500 nm. c. It is reasonable to conclude that light absorbance is maximum at 600 nm. d. It is reasonable to conclude that light absorbance is maximum at 700 nm. e. The frequency for maximum light absorbance cannot be determined from the data provided 8. The dependent variable measured in this experiment is the. (PT1-97) a. Percent transmittance through the solutions b. Time exposed to light c. Amount of photosynthesis taking place d. Presence or absence of chloroplasts e. Frequency of light to which the solutions were exposed 2

3 Question 9 refers to the following graph that shows the relationship between CO 2 uptake by leaves and the concentrations of O 2 and CO 2 in growth chambers. 9. According to the graph, relative CO 2 uptake increases as O 2 concentration decreases. This can be explained best by which of the following? (PT2-93) a. O 2 is not necessary for photosynthesis b. As O 2 concentration decreases, CO 2 increases c. As O 2 concentration increases, CO 2 decreases d. O 2 competes with CO 2 for RuBP carboxylase activity e. A higher concentration of O 2 causes an increase in the relative CO 2 uptake 10. During hibernation, the rate of cellular respiration in a mammal is typically less than half the rate measured when the mammal is not hibernating. Such slowed cellular respiration is probably accompanied by which of the following? (1994-2) Pulse Rate Body Temperature a. Reduced Reduced b. Unchanged Reduced c. Reduced Increased d. Unchanged Increased e. increased Reduced 11. Which of the following is an important difference between light-dependent and lightindependent reactions of photosynthesis? ( ) a. The light-dependent reactions occur only during the day; the light independent reactions occur only during the night b. The light-dependent reactions occur in the cytoplasm; the light independent reactions occur in the chloroplasts c. The light-dependent reactions utilize CO 2 and H 2O; the light-independent reactions produce CO 2 and H 2O d. The light-dependent reactions depend on the presence of both photosystems I and II; the light-independent reactions require only photosystem I e. The light-dependent reactions depend on the presence of both photosystems I and II; the light-independent reactions use energy stored in ATP and NADPH 12. Which metabolic process is common to both aerobic cellular respiration and alcoholic fermentation? ( ) a. Krebs cycle b. Glycolysis c. Electron Transport Chain d. Conversion of pyruvic acid to acetyl CoA e. Production of a proton gradient 3

4 Questions refer to the following graph and information. 13. The rate of pyruvic acid formation fluctuates because. ( ) a. All glucose has reacted b. All enzymes have been used up c. The reaction is accelerated by positive feedback d. The reaction is affected by negative feedback e. Coenzymes have begun to function 14. Which of the following is most likely to result if oxygen is added to the tissue culture? ( ) a. Lactic acid formation will increase b. For each glucose molecule consumed, more ATP will be formed c. The levels of ATP produced will decrease d. Ethyl alcohol will be produced e. No change in the production of pyruvic acid will be observed 15. All of the following are common to C 3 and C 4 photosynthesis EXCEPT. ( ) a. Photolysis b. Initial step of CO 2 fixation c. Cyclic photophosphorylation d. Non-cyclic photophosphorylation e. Chemiosmotic photophosphorylation Question 16 refers to the molecules of the following substances. ( ) (A) FADH2) (B) NAD+ (C) NADP+ (D) Oxygen 16. Coenzyme that transfers electrons from the Krebs cycle to the mitochondrial electrontransport chain at a lower energy level than that of electrons entering at the beginning of the chain (A) 17. Metabolism of which of the following molecules results in the greatest net usable energy per gram? (2008-7) a. A triglyceride b. A tripeptide c. An alpha-linked disaccharide d. A beta-linked disaccharide e. An anabolic steroid 4

5 18. A scientist studying the oxygen concentration in sealed chambers containing cultured plant cells find that when the chambers are illuminated, the concentration of oxygen increases. However, when the chambers are kept in the dark, the concentration of oxygen decreases. Why does the oxygen concentration decrease when the chamber is kept in the dark? ( ) a. Plant cell mitochondria consume oxygen by aerobic respiration b. Plant cell chloroplasts run the photosynthetic pathways backward to consume oxygen c. Plant cell chloroplasts switch their structure and function and become mitochondria d. The chambers must not be properly sealed, so that oxygen is leaking out e. The cultures in the chambers must be contaminated with some animal cells, since only animal cells consume oxygen 19. Which of the following occurs in both fermentation and aerobic cellular respiration? ( ) a. Oxygen and carbon dioxide are consumed b. FAD is reduced, driving ATP synthesis c. Proton gradients are produced across membranes d. ATP is synthesized from ADP and inorganic phosphate e. Most of the energy from glucose is released as carbon dioxide. Questions refer to an experiment that is set up to determine the relative volume of O 2 consumed by germinating and non-germinating (dry) pea seeds at two different temperatures. The change in volume is detected by using a respirometer over a given period of time. The data are given below. 20. The rate of oxygen consumption in germinating pea seeds at 26 C is. ( ) a ml/min b ml/min c ml/min d ml/min e ml/min 21. Which of the following conclusions is best supported by the data? ( ) a. Non-germinating pea seeds have a higher rate of respiration than germinating pea seeds do b. Light is required for pea seed germination c. In the non-germinating pea seeds, oxygen consumption is directly proportional to oxygen concentration d. Less carbon dioxide is produced by germinating pea seeds at 26 C than at 10 C. e. In pea seeds an increase in temperature results in an increase in oxygen consumption 5

6 Questions A new species of succulent epiphytic flowering plant was discovered in the canopy of a tropical rainforest. Experiments were carried out to determine the plant s photosynthetic capacity by measuring the net uptake of carbon dioxide and changes in tissue starch concentration over a 32-hour period with 8 hours of dark at the start and end of the measurement period and 16 hours of moderate light between the dark periods. The changes in the rate of carbon dioxide uptake and the concentration of tissue starch are shown in the diagram below. ( ) 22. Which of the following is consistent with the data? ( ) a. The highest rate of carbon dioxide uptake occurs at the beginning of the light period b. The highest rate of carbon dioxide uptake occurs at the beginning of the dark period c. The highest rate of carbon dioxide uptake occurs near the end of the dark period d. The highest starch concentration occurs at the beginning of the light period e. The lowest starch concentration occurs at the end of the light period 23. A useful control for the experiment would have included which of the following? ( ) I. Expose the plant to 32 hours of continuous moderate light and measure rates of carbon dioxide uptake and tissue starch concentration II. Expose the plant to 32 hours of continuous dark and measure rates of carbon dioxide uptake and tissue starch concentration III. Measure the chlorophyll concentration in the plant s leaf tissue a. I only b. II only c. III only d. I and II only e. I, II, and III 24. The function of water in photosynthesis is to ( ) a. Combine with CO 2 b. Absorb light energy c. Supply electrons in the light-dependent reactions d. Transport H + ions in the light-independent (dark) reactions e. Provide O 2 for the light-independent (dark) reactions Cellular Respiration Questions Photosynthesis Questions