BIOC 305 Final Exam Winter 2015 ***PRACTICE EXAM *** Multiple Choice (45 questions, 1 point each) 1. Which of the following statements about DNA methylation is TRUE?

I. Methylation plays a role in genomic imprinting. II. Methylation can influence gene regulation. III. Methylation plays a role in restriction modification systems. IV. Methylation occurs in prokaryotic cells, but not eukaryotic cells.

A) I, II, III, IV B) I, II, III C) II, III D) II, III, IV E) II only

2. Histone H1 binds to ____ which allows attachment to _____. A) the nucleosome core particle; nucleases B) linker DNA; the next nucleosome C) the nucleosome core particle; the next nucleosome D) linker DNA; nucleases E) none of the above

3. Defects in the proteins ______, which associate with RAD-51, are correlated with several types of cancer.

A) BRCA1 and BRCA2 B) RecU and RecB C) Pol and Pol D) DSB and NHEJ E) RecA and RecUGA

4. Which of the following sequences, if double stranded, would likely be a recognition site for a restriction enzyme?

A) 5' TGAGCA3' B) 5' TGATCA3' C) 5' TACGTCA3' D) All of the above would bind the repressor with equal efficiency E) None of the above would bind would the repressor

5. Nucleosomes I. bind specifically to palindromic DNA sequences II. are bound together by linker histones. III. contain a lipid bilayer IV. contain a histone octamer

A) I, II, IV B) II, III C) III, IV D) I, IV E) II, IV

6. The symptoms of LeschNyhan syndrome are caused by a deficiency of A) adenine phosphoribosyltransferase B) HGPRT (hypoxanthineguanine phosphoribosyltransferase) C) adenosine deaminase D) dihydrofolate reductase E) xanthine oxidase

7. Which of the choices correctly represents the synthesis of dTTP as represented by the following reactions?

I. dUMP + N5,N10-methylenetetrahydrofolate dTMP + dihydrofolate

II. dTMP + ATP dTTP + Pi III. dUTP + H2O dUMP + PPi IV. dUTP + N5,N10-methylenetetrahydrofolate dTTP + dihydrofolate

A) I II IV B) IV only C) III IV I II D) III I II E) III I

8. Which of the following organisms excrete uric acid? I. primates II. marine invertebrates III. insects IV. mammals other than primates

A) I, IV B) I, III C) IV only D) I only E) II, III

9. Which of the following statements is TRUE? A) AMPK generally activates pathways that consume ATP B) AMPK becomes activate when [AMP] is at its lowest. C) Insulin phosphorylates AMPK D) AMP binding to AMPK leads to activation of AMPK E) AMPK converts AMP to ADP

10. The end products of pyrimidine catabolism are

A) uric acid and glyoxylic acid. B) uric acid and allantoin. C) malonyl-CoA and methylmalonyl-CoA. D) -alanine and -ketoglutarate. E) none of the above

11. Addition of pyrophosphate to which of the following occurs during the first step of purine biosynthesis?

A) 5-phosphoribosyl phosphate B) ribulose-5-phosphate C) ribose-5-phosphate D) ribose E) phosphribosylamine

12. Glycine contributes to the ring at position _____.

A) A B) B C) C D) D E) E

13. Glucose is the preferred fuel of muscles because A) it can be metabolized under anaerobic conditions. B) it can be generated from ketone bodies even during starvation. C) the heart muscle uses glucose exclusively as a fuel. D) it is the most efficient energy storage available. E) all of the above

14. The metabolic fate(s) of glucose-6-phosphate include

I. glycogen and glucose. II. ribose-5-phosphate III. acetyl-CoA. IV. DNA and RNA.

A) I B) I, II C) I, III D) III, IV E) I, II, III, IV

15. Choose the FALSE statement. A) The liver performs gluconeogenesis. B) The liver produces ketone bodies when energy demand is high C) The liver converts fatty acids to acetyl-CoA. D) The liver consumes fatty acids for fuel when blood glucose is low. E) The liver uses amino acids as fuel.

16. Which of the following proteins stimulates the appetite?

A) leptin B) ghrelin C) adiponectin D) insulin E) PYY3-36

17. Which of the following statements is TRUE regarding the blood glucose level of non-insulin dependent diabetics compared to that of normal individuals?

A) Blood glucose levels of diabetics tend to be very stable, but at a higher level.

B) Blood glucose levels of diabetics tend to be variable and higher. C) Blood glucose levels decrease more rapidly following a meal, often

dropping lower than is tolerable. D) Blood glucose levels average the same level in diabetics, but reach higher

peaks for short periods. E) none of the above

18. In reference to the graph shown below, which of the following statements is true?

A) Curve A represents glucokinase in liver. B) Curve A represents hexokinase in liver. C) Curve A represents hexokinase in muscle. D) Curve B represents hexokinase in muscle. E) Curve B represents glucokinase in muscle.

19. The majority of glucose in the brain A) is used to store adequate glycogen for extended periods of starvation. B) is used to produce ATP for membrane Na+-K+ ATPase required for nerve

impulse transmission. C) is synthesized from fatty acids due to the need for high ATP levels. D) is synthesized in the adipose tissue and transported to the brain. E) is synthesized from ketone bodies under conditions of prolonged fasting.

20. Which of the following can generate glucose? I. kidney II. liver III. adipose tissue IV. muscle

A) I, II, III, IV B) I, II, IV C) I, II D) II, IV E) II only

21. Glucose uptake A) in the liver is mediated by GLUT4. B) in the muscle is increased in response to insulin due to increased

expression of GLUT4. C) in the brain is adjusted relative to the concentration of glucose. D) A and B E) A, B, C

22. Activation of AMPK activity is A) accomplished by AMP induced conformational changes facilitating

phosphorylation. B) accomplished by ATP induced conformational change facilitating

phosphorylation. C) inhibited by high levels of AMP due to conformational changes burying

the phosphorylation site. D) increased by high levels of ATP due to conformational changes burying

the phosphorylation site. E) none of the above

23. Which of the following are characteristics of metabolic syndrome?

I. insulin resistance II. inflammation III. increased risk for type 1 diabetes. IV. hypersensitivity to insulin

A) I, II B) I, II, III C) I, II, III, IV D) I, III E) I only

24. Which of the following does not use an aminotransferase in the first step of its synthesis? A) glutamine B) alanine C) aspartate D) glycine E) none of the above

25. Which of the following is an immediate precursor of glutamate?

A) -ketoglutarate. B) pyruvate. C) ornithine. D) acetyl-CoA E) succinyl-CoA

26. Which of the following statements about bilirubin is FALSE? A) light accelerates its breakdown B) it is a product of heme breakdown C) it is hydrophilic D) it is present only when the liver is damaged E) it causes jaundice

27. The diagram represents a substrate cycle in glucose metabolism. Which of the following statements about the cycle is true?

A) Reactions I & II are catalyzed by the same enzyme and help establish

equilibrium between the two metabolites. B) Reaction II produces ATP by substrate-level phosphorylation. C) Reaction II is catalyzed by an allosteric enzyme that is inhibited by

fructose-2-6-bisphosphate. D) Reaction I is involved in the biosynthesis of glucose. E) Reaction II occurs under low-energy conditions when the cell needs ATP.

28. In skeletal muscle cells, oxidation of NADH generated from anaerobic glycolysis occurs

during which of the following reactions? A) acetaldehyde ethanol B) lactate pyruvate C) phosphoenolpyruvate pyruvate D) pyruvate lactate E) glyceraldehyde-3-phosphate 1,3-bisphosphoglycerate

29. Which enzyme is involved in substrate level phosphorylation in glycolysis?

A) hexokinase B) pyruvate kinase C) glyceraldehyde-3phosphate dehydrogenase D) aldolase E) none of the above.

30. Muscle cells are not able to supply glucose for other tissues because

A) they lack the GLUT2 transporter. B) they lack pyruvate carboxylase. C) they lack glucose-6-phosphatase. D) they lack the malate-aspartate shuttle. E) they lack glycogen phosphorylase.

31. Which of the following uses inherent length and flexibility to facilitate transfer of an acetyl group as a swing arm in catalysis?

A) FAD B) NAD+ C) lipoamide D) thiamine pyrophosphate E) coenzyme A

32. Germinating plant seeds can convert acetyl-CoA (obtained from fatty acids stored as oils) into carbohydrates, whereas animals are incapable of converting fatty acids into glucose. This difference is due to the fact that:

A) animals have glycogen and dont need to make glucose from fatty acids. B) plants use the glyoxylate cycle to convert two acetyl CoA to oxaloacetate,

a precursor for gluconeogenesis. C) plant seeds use photosynthesis to make sugar. D) animals use the citric acid cycle selectively for energy production,

whereas plants primarily use glycolysis. E) most animal cells lack complete pathways for gluconeogenesis

33. Which of the following represents a point of regulation for the citric acid cycle? I. pyruvate dehydrogenase complex II. aconitase III. enolase IV. lactate dehydrogenase

A) I, II, III, IV B) I, II, IV C) II, III D) I E) I, IV

34. One method used by newborn mammals to generate heat is referred to as nonshivering

thermogenesis. This method utilizes a protein channel called ________ which is present in high levels inside the mitochondria of _____tissue.

A) thermogenin; muscle B) UCP-1; muscle C) thermogenin; brown adipose D) UCP-1; white adipose E) UCP-2; brown adipose

35. Which of the following is TRUE regarding the complexes within the mitochondrial electron transport system? I. Complex II contributes twice as many protons to the gradient than Complex I II. Inhibition of Complex II would decrease the total number of electrons

moving through the electron transport chain. III. Inhibition of Complex II would not alter the amount of free energy generated

from electrons originating from NADH. IV. Complex I passes electrons with high potential to Complex II.

A) I, II, III, IV B) I, II, III C) II only D) II, III E) III, IV

36. The structure of ATP synthase changes in conformation as a result of

A) the rotation of the and subunits. B) the rotation of the subunit. C) the rotation of ATP. D) the rotation of the subunit. E) all of the above.

37. A deficiency in the enzyme PEPCK (PEP carboxykinase) would

A) block function of the malate/aspartate shuttle. B) block transfer of reducing equivalents across the membrane in the heart and

liver. C) inhibit formation of ATP via oxidative phosphorylation. D) inhibit formation of NADH. E) decrease flux through gluconeogenesis.

38. Which statement(s) concerning the mitochondrial F0F1 ATP synthase is FALSE?

I. The F1 subunit includes rotating sets of dimers. II. The F0 subunit includes a ring of between 9 and 12 proton-carrying polypeptides. III. The F1 subunit undergoes a series of conformational changes throughout the course of reaction.

A) I, II, III B) II, III C) I only D) III only E) None of the options (I III) is false. Options I-IV are all true.

39. Which of the following is a substrate in the reaction that leads most directly to glycogen synthesis?

A) Glc-1-P B) Glc-6-P C) UDP-Gal D) UDP-Glc E) Glc-GTP

40. Flux through the pentose phosphate pathway is regulated by A) Glc-6-P kinase B) glucokinase C) Glc-6-P phosphatase D) glucosyltransferase E) Glc-6-P dehydrogenase

41. The malate-aspartate shuttle is important for transporting the equivalent of A) glycine B) oxaloacetate C) lactate D) alanaine E) acyl-CoA

42. What an input and output of ketogenesis?

A) hydroxybutyrate; acetyl-CoA B) pyruvate; -ketoglutarate C) acetlyl-CoA; acetoacetate D) pyruvate; acetone E) Glc-6-P; acetoacetone

43. Chylomicrons are A) lipoproteins B) lipases C) apolipoproteins D) micelles E) endosomes

44. Why is ammonia toxic? A) it inhibits hexokinase B) it depletes -ketoglutarate C) it competes with ATP in many reactions D) it inhibits pyruvate kinase E) it denatures proteins

45. Specific proteins are targeted for degradation using A) lysosomes B) restriction enzymes C) endosomes D) lipases E) E3 ubiquitin-protein ligase