BIOS102- 250 Fall 2012 Sample Second Exam MULTIPLE CHOICE. Choose the one alternative that best completes the statement or answers the question. 1) Which of the following statements describes NAD + ? A) In the absence of NAD + , glycolysis can still function. B) NAD+ is reduced to NADH during glycolysis, pyruvate oxidation, and the citric acid cycle. C) NAD+ can donate electrons for use in oxidative phosphorylation. D) NAD+ has more chemical energy than NADH. E) NAD+ is oxidized by the action of hydrogenases. ) During glycolysis, when each molecule of glucose is catabolized to two molecules of pyruvate, most of the potential energy contained in glucose is A) stored in the NADH produced. B) transferred directly to ATP. C) transferred to ADP, forming ATP. D) retained in the two pyruvates. E) used to phosphorylate fructose to form fructose 6 – phosphate. 3) Starting with one molecule of glucose, the energy – containing products of glycolysis are A) 6 CO2 , 30 ATP, and 2 pyruvate. B) 2 NAD+ , 2 pyruvate, and 2 ATP. C) 6 CO2 , 2 ATP, and 2 pyruvate. D) 2 FADH2 , 2 pyruvate, and 4 ATP. E) 2 NADH, 2 pyruvate, and 2 ATP. ) Why is glycolysis described as having an investment phase and a payoff phase? A) It uses stored ATP and then forms a net increase in ATP. B) It both splits molecules and assembles molecules. C) It uses glucose and generates pyruvate. D) It attaches and detaches phosphate groups. E) It shifts molecules from cytosol to mitochondrion. 5) The primary role of oxygen in cellular respiration is to A) combine with lactate, forming pyruvate. B) yield energy in the form of ATP as it is passed down the respiratory chain. C) act as an acceptor for electrons and hydrogen, forming water. D) combine with carbon, forming CO 2 .
E) catalyze the reactions of glycolysis. 6) In liver cells, the inner mitochondrial membranes are about five times the area of the outer mitochondrial membranes. What purpose must this serve? A) It increases the surface for oxidative phosphorylation. B) It allows for an increased rate of glycolysis. C) It increases the surface for substrate – level phosphorylation. D) It allows the liver cell to have fewer mitochondria. E) It allows for an increased rate of the citric acid cycle. 1 7) In the absence of oxygen, yeast cells can obtain energy by fermentation, resulting in the production of A) ATP, pyruvate, and acetyl CoA.
B) ATP, CO2 , and lactate. C) ATP, NADH, and pyruvate. D) ATP, pyruvate, and oxygen. E) ATP, CO2 , and ethanol (ethyl alcohol). 8) Phosphofructokinase is an allosteric enzyme that catalyzes the conversion of fructose 6 – phosphate to fructose 1,6- bisphosphate, an early step of glycolysis. In the presence of oxygen, an increase in the amount of ATP in a cell would be expected to A) inhibit the enzyme and thus increase the rates of glycolysis and the citric acid cycle. B) activate the enzyme and thus slow the rates of glycolysis and the citric acid cycle. C) inhibit the enzyme and thus slow the rates of glycolysis and the citric acid cycle.
D) inhibit the enzyme and thus increase the rate of glycolysis and the concentra tion of citrate. E) activate the enzyme and increase the rates of glycolysis and the citric acid cycle. 9) Which of the events listed below occurs in the light reactions of photosynthesis? A) Carbon dioxide is incorporated into PGA. B) NADP is produced. C) Light is absorbed and funneled to reaction – center chlorophyll a. D) ATP is phosphorylated to yield ADP. E) NADPH is reduced to NADP + . 10) Which of the following statements best describes the relationship between photosynthesis and respiration?
A) Respiration is anabolic and photosynthesis is catabolic. B) ATP molecules are produced in photosynthesis and used up in respiration. C) Photosynthesis stores energy in complex organic molecules, whereas respiration releases it. D) Photosynthesis occurs only in plants and respiration occurs only in animals. E) Respiration runs the biochemical pathways of photosynthesis in reverse. 11) In thylakoids, protons travel through ATP synthase from the thylakoid space to the stroma. Therefore, the catalytic ? knobs? of ATP synthase would be located A) on the ATP molecules themselves.
B) built into the center of the thylakoid stack (granum). C) on the pigment molecules of photosystem I and photosystem II. D) on the stromal side of the membrane. E) on the side facing the thylakoid space. 12) What is the primary function of the Calvin cycle? A) use ATP to release carbon dioxide B) use NADPH to release carbon dioxide C) synthesize simple sugars from carbon dioxide D) split water and release oxygen E) transport RuBP out of the chloroplast 2 13) Photorespiration occurs when rubisco reacts RuBP with A) 3 – phosphoglycerate. B) CO 2 . C) O2 . D) glyceraldehyde 3 – phosphate. E) NADPH. 4) Compared to C 3 plants, C 4 plants A) make a four- carbon compound, oxaloacetate, which is then delivered to the citric acid cycle in mitochondria. B) have higher rates of photorespiration. C) can continue to fix CO 2 even at relatively low CO2 concentrations and high oxygen concentrations. D) grow better under cool, moist conditions. E) do not use rubisco for carbon fixation. 15) Taxol is an anticancer drug extracted from the Pacific yew tree. In animal cells, Taxol disrupts microtubule formation by binding to microtubules and accelerating their assembly from the protein precursor, tubulin. Surprisingly, this stops mitosis.
Specifically, Taxol must affect A) the formation of the mitotic spindle. B) the S phase of the cell cycle. C) formation of the centrioles. D) chromatid assembly. E) anaphase. 16) Measurements of the amount of DNA per nucleus were taken on a large number of cells from a growing fungus. The measured DNA levels ranged from 3 to 6 picograms per nucleus. In which stage of the cell cycle did the nucleus contain 6 picograms of DNA? A) G1 B) G0 C) M D) S E) G2 17) What is a cleavage furrow? A) a ring of vesicles forming a cell plate B) the metaphase plate where chromosomes attach to the spindle C) the separation of divided prokaryotes
D) the space that is created between two chromatids during anaphase E) a groove in the plasma membrane between daughter nuclei 18) Which of the following describe(s) cyclin- dependent kinase (Cdk)? A) Cdk is present throughout the cell cycle and is an enzyme that attaches phosphate groups to other proteins. B) Cdk is inactive, or ? turned off,? in the presence of cyclin. C) Cdk is an enzyme that attaches phosphate groups to other proteins. D) Cdk is inactive, or ? turned off,? in the presence of cyclin and it is present throughout the cell cycle.
E) Cdk is present throughout the cell cycle. 3 19) Why do neurons and some other specialized cells divide infrequently? A) They no longer carry receptors for signal molecules. B) They no longer have active nuclei. C) They have been shunted into G 0 . D) They can no longer bind Cdk to cyclin. E) They show a drop in MPF concentration. 20) For a chemotherapeutic drug to be useful for treating cancer cells, which of the following is most desirable? A) It only attacks cells that are density dependent. B) It interferes with cells entering G0 . C) It interferes with rapidly dividing cells.