Multiple Choice. Choose the BEST answer !!

1. Suppose that compound A accepts electrons from compound B. What has happened to compound A?

A. It has been oxidized.
B. It has been reduced.
C. It has more energy.
D. A and C are correct.
E. B and C are correct.

2. Which of the following is not produced in any of the steps of glycolysis?

A. NAD+
B. NADH
C. ADP
D. ATP
E. Pyruvate

3. When a muscle cell metabolizes glucose in the complete absence of molecular oxygen, all of the following substances are produced except

A. NADH
B. ATP
C. Pyruvate
D. Lactic acid
E. Acetyl-CoA

4. Which of the following statements is the most accurate?

A. Pyruvate contains more energy than ethanol because it appears earlier in the anaerobic metabolism of glucose.
B. Pyruvate contains less energy than ethanol because NADH donates electrons to a precursor of ethanol.
C. Pyruvate and ethanol have equal amounts of energy, although ethanol is produced only by microorganisms.
D. Pyruvate does not change its energy content as ethanol is formed during the anaerobic metabolism of glucose.
E. Pyruvate becomes oxidized to ethanol as NAD+  is reformed during the anaerobic metabolism of glucose.
 

5. Which of the following does not produce carbon dioxide?

A. a  plant cell in the dark
B. a yeast cell under anaerobic conditions
C. a mitochondrion under aerobic conditions
D. muscle cells under anaerobic conditions
E. a plant cell in the light

6. The enzymes that catalyze the reactions of the Krebs cycle are found in which subcellular organelle in eukaryotes?

A. chloroplast
B. ribosome
C. lysosome
D. mitochondrion
E. endoplasmic reticulum

7. When pyruvate is converted to acetyl-CoA

A. NADH and carbon dioxide are formed.
B. NADH and ATP are formed.
C. carbon dioxide and ATP are formed.
D. NADH is formed.
E. carbon dioxide, NADH, and ATP are formed.
 
 
 

8. A principal product of the Krebs cycle is

A acetyl-CoA.
B. citric acid.
C. ADP
D. oxidized electron carriers.
E. reduced electron carriers.

9. How many ATP molecules are synthesized directly in the Krebs cycle if you supply an aerobically respiring cells with 10 pyruvate molecules?

A. 2
B. 5
C. 10
D. 20
E. 300

10. In cellular metabolism, O2 is used

A. to provide electrons for photophosphoryation.
B. in glycolysis.
C. in fermentation.
D. as a terminal electron acceptor.
E. in the Krebs cycle.

11. Where is the respiratory electron transport chain located in a plant cell?

A. in the thylakoid membrane of the chloroplast
B. in the inner membrane of the chloroplast
C. in the outer membrane of the chloroplast
D. in the inner membrane of the mitochondrion
E. in the outer membrane of the mitochondrion

12. The chemiosmotic generation of ATP is driven by

A. osmotic movement of water into an area of high solute concentration.
B. The addition of protons to ADP and phosphate using enzymes.
C. A difference in hydrogen ion concentration on either side of a membrane.
D. Substrate-level phosphorylation.
E. None of the above.

13. Which of the following statements best describes the relationship between photosynthesis and respiration?

A. Respiration is the exact reversal of the biochemical pathways of photosynthesis.
B. Photosynthesis stores energy in complex organic molecules and respiration releases it.
C. ATP molecules are produced in photosynthesis and used in respiration.
D. Photosynthesis occurs only in plants and respiration occurs only in animals.
E. Respiration requires a proton gradient and photosynthesis does not.

14. The ultimate fate of an oxygen atom that begins the photosynthetic process as part of a water molecule is to

A. combine with a free oxygen atom to become oxygen gas.
B. reassociate with hydrogen ions to become a new molecule of water.
C. reassociate with free carbon and oxygen atoms to become carbon dioxide gas.
D. become part of the carbohydrate product made in the Calvin cycle.
E. combine with carbon dioxide to become glucose.
 
 
 
 
 

15. Suppose that you use a specific poison to prevent water from being split during photosynthesis. Which of the following would continue to take place?

A. oxygen production
B. reduction of carbon dioxide
C. synthesis of ATP
D. transport of electrons from one photosystem to another
E. reduction of NADP+

16. When a chlorophyll molecule in photosystem I traps light, it loses an electron. In noncyclic electron flow this electron is replaced

A. from one of the antenna pigments.
B. from the other end of photosystem I.
C. by a donation from photosystem II.
D. by a donation from an unexcited chlorophyll molecule.
E. from one of the hydrogen atoms in water.

17. Which of the following compounds are both products of the light reactions in photosynthesis and also reactants in the dark reactions?

A. NADPH and O2
B. NADPH and ATP
C. NADP+ and CO2
D. NADP+ , ATP, and CO2
E. NADP+, ATP and O2

18. In chemiosmotic synthesis of ATP during photosynthesis, the hydrogen ions diffuse from the

A. stroma to the thylakoid interior.
B. cytoplasm to cross the outer chloroplast membrane.
C. stroma to cross the inner chloroplast membrane.
D. thylakoid interior to the stroma.
E. space between the inner and outer membranes to enter the stroma.

19. In the dark (light-independent) reactions of photosynthesis

A. carbon dioxide is incorporated into an organic molecule.
B. oxygen is produced.
C. ATP is made.
D. A and C are correct.
E. A, B, and C are correct.

20. Carbon dioxide is reduced in

A. cyclic photophosphorylation.
B. noncyclic photophosphorylation.
C. the light reactions of photosynthesis.
D. the Calvin cycle.
E. Both the light and dark (light-independent) reactions of photosynthesis.

21. The reason why C4 plants can fix relatively more carbon than C3 plants when oxygen concentration in the plant cell is high is that

A. the plants do not have rubisco.
B. the plants have rubisco.
C. the initial carbon dioxide fixation enzyme cannot use oxygen as a substrate.
D. carbon enters the Calvin cycle directly from the air.
E. they utilize a process called photorespiration.
 
 

22. Chromosomes

A. contain genes in the form of proteins that code for DNA.
B. contain proteins in the form of DNA that code for genes.
C. contain genes in the form of DNA that code for proteins.
D. contain DNA in the form of proteins that code for genes.
E. contain proteins in the form of genes that code for DNA.

23. Which statement correctly compares mitosis and meiosis?
 
A. Sister chromatids split during both mitosis and meiosis I.
B. Sister chromatids split during mitosis, never during meiosis.
C. Sister chromatids do not split during mitosis or meiosis II.
D. Sister chromatids split during mitosis and meiosis II.
E. Sister chromatids split during meiosis I and meiosis II but not during mitosis.
 

24.   Scientists studying the cell cycle measured the DNA content of non-dividing cells and
determined that the diploid amount per cell was 3 picograms. They then measured a cycling cell
population and the amount of DNA ranged from 3.5 to 5.5 picograms. These cells were most likely
in

A.   G1.
B.   S.
C.   G2.
D.   G1 or G2.
E.   G1 or S.

25. During meiosis, the sister chromatids separate during

A.   anaphase II.
B.   anaphase I.
C.   S phase.
D. Prophase I.
E. never separate.

26. The total DNA content of each daughter cell is reduced during meiosis because

A.   chromosomes do not replicate during the interphase before meiosis I.
B.   chromosomes do not replicate during interphase between meiosis I and meiosis II.
C.   half of the chromosomes from each gamete are lost during fertilization.
D.   sister chromatids separate during anaphase of meiosis I.
F. chromosome arms are lost during crossing over.

27. How many chromatids would you expect to find at that stage in the mitotic cycle when the nuclear membrane disappears in a cell whose diploid number is 10?

A. 0
B. 5
C. 10
D. 20
E. 40

28. A diploid cell contains 14 chromosomes. At the end of meiosis I, each of the resulting cells most probably contains

A. 7 maternally derived or 7 paternally derived chromosomes.
B. a mixture of maternally derived and paternally derived chromosomes adding up to 7.
C. 14 maternally derived or 14 paternally derived chromosomes.
D. a mixture of maternally derived and paternally derived chromosomes adding up to 14.
E. 14 tetrads consisting of 7 maternally derived and 7 paternally derived chromosomes each.
 

29. Homologous pairs of chromosomes form a tetrad during meiosis as a result of  (select the most complete answer)

A. replication of chromosomes during prophase of meiosis I and synapsis during meiosis II.
B. replication of chromosomes during the S phase preceding meiosis I and synapsis during meiosis II.
C. replication of chromosomes during the S phase preceding meiosis I and synapsis during anaphase of meiosis I.
D. replication of chromosomes during the S phase preceding meiosis I and synapsis during prophase of meiosis I.
E. replication of chromosomes during the S phase preceding meiosis II and synapsis during prophase of meiosis II.

30. In which of the following processes is most genetic variation generated?

A. first meiotic division
B. second meiotic division
C. S phase preceding mitosis
D. mitosis
E. S phase preceding the first meiotic division
 

Choose the best term from the following list to answer questions 31-35. Terms can be used more than once or not at all. If no term is appropriate, answer E.

A. chromatin
B. sister chromatids
C. homologous chromosomes
D. tetrad

31. Complex of DNA and histone proteins in the nucleus of eukaryotic cells. _____
32. Forms just prior to synapsis and crossing over. _____
33. Forms during S phase. ____
34. Consists of four chromatids. ____
35. Held together by a centromere. _____

Choose the best term from the following list to answer questions 36-40. Terms can be used more than once or not at all. Answer E if no correct term appears.

A. gamete
B. zygote
C. fertilization
D. recombination

36. Produced by meiosis. _____
37. Creates the diploid cell. _____
38. Unites gametes. _____
39. Is haploid. _____
40. Requires a tetrad. _____

Questions 41-50 are true or false. Answer A for true or B for false.

41. In the Hershey-Chase experiment, the radioactive P32 was found inside the infected cell. _____
42. During meiosis I, tetrads align along the metaphase plate with maternal chromatids on one side and paternal chromatids on the other in most cases. _____
43. Frederick Griffith demonstrated that mice could be killed only if a capsule was present around the bacteria that infected the mice. _____
44. Diploid cells have 4n of genetic material in G2 of the cell-cycle. _____
45. Recombination occurs during mitotic prophase. _____
46. Sister chromatids separate during meiosis II and during mitosis. _____
47. Homologous chromosomes can have different genes. _____
48. Mitosis produces two genetically identical daughter cells. _____
49. Meiosis produces four genetically different daughter cells. _____
50. Crossing-over occurs between sister chromatids. _____