Final Review Worksheet Chem 103, Winter 2006

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Final Review Worksheet

Chem 103, Winter 2006

1. Draw an example of each of the following: a) an aldopentose b) a ketotriose

2. Consider the monosaccharide galactose. a) Draw the Fischer projection for L-galactose. b) What is the stereochemical relationship between L-galactose and D-galactose? c) What is the stereochemical relationship between D-galactose and D-glucose? d) What must happen to D-galactose before it can enter glycolysis? e) Draw the Haworth structure for

-L-galactose

3. What is mutorotation?

4. Suppose that you have two sugar solutions, one is sucrose and the other is maltose.

Unfortunately, you forgot to label them and have now got them mixed up. What experiments could you do (besides measuring optical rotation) to determine which solution is which, and how would you tell?

5. How would you synthesize D-glucitol (D-sorbitol)? Write out the reaction, including structures and reagents.

6. Draw the structure for the product you would get by reacting D-glucose with methanol and an acid catalyst.

7. Maltose is a disaccharide obtained from starch. a) Draw the structure of

-maltose. b) What type of glycosidic bond does maltose have? c) Maltose is used for brewing malt beverages (like beer). Explain how maltose is converted to ethanol. Include all reaction steps. d) Is maltose a reducing sugar? Why or why not?

8. Suppose that you are attempting to hydrolyze lactose. a) What reagents could you use for the hydrolysis? b) How could you test the reaction solution to see if the hydrolysis worked?

9. What is the difference between amylose and amylopectin?

10. Iodine forms a dark blue complex with amylose, but not with cellulose. Explain why.

11. What is a lipid?

12. Which types of lipids do not contain fatty acid chains?

13. Would you expect trans-fatty acids to be liquids or solids at room temperature?

Explain why or why not.

14. How does an NSAID, such as ibuprofen, reduce pain and swelling from an injury?

15. How is a wax related to a fatty acid?

16. What is the main function of triacylglycerides?

17. Why are fats generally solid at room temperature, while oils are generally liquids at room temperature?

18. Trans fats are formed during traditional methods for the hydrogenation of unsaturated oils. Write the reaction for the hydrogenation of cis-oleic acid,

CH

3

(CH

2

)

7

CH=CH(CH

2

)

7

CH

3

, and show how trans-oleic acid could form during the reaction.

19. Show the products for the oxidation of oleic acid, CH

3

(CH

2

)

7

CH=CH(CH

2

)

7

CH

3

.

20. What is saponification? Show an example of a saponification reaction.

21. What are the main functions of glycerophospholipids, and how does their structure make them suited for those roles?

22. Draw a diagram of the general structure of a glycosphingolipid. What are the main functions of glycosphingolipids?

23. Draw the steroid nucleus.

24. Too much cholesterol is bad. However, cholesterol is essential for our cells. a) What are the main functions of cholesterol? b) How do vegetarians get cholesterol?

25. What are HDL and LDL, and what are their functions?

26. Where, and from what, are bile salts synthesized and what are their main functions?

27. Where are steroid hormones synthesized and what is their general function?

28. What are the roles of each of the following in cell membranes? a) cholesterol b) glycoproteins c) integral proteins

29. What is the difference between simple and facilitated transport?

30. Which of the nonpolar amino acids can participate in H-bonding?

31. The pI for serine is 5.7. Draw the structure of serine at the following pH’s: a) 5.7 b) 9.0

32. Draw the Fischer projection for D-leucine. c) 3.0

33. Suppose that you have a mixture of amino acids from a protein that you are analyzing. How could you use electrophoresis to determine which amino acids are present in the mixture?

34. Peptides are resistant to hydrolysis than triacylglycerides. Explain what gives peptides their special stability. Use drawings to illustrate your answer.

35. Draw the structure for Cys-Tyr-Ile

36. What type of secondary structure predominates in keratin?

-keratin? What type in

37. What is the primary type of cross-linking in secondary structure?

38. Describe the structure of collagen and explain what makes it so strong.

-

39. What is a salt bridge? Show an example.

40. Are enzymes typically globular or fibrous proteins?

41. How do heavy metal ions denature proteins?

42. What is a catalyst?

43. What are the two main overall purposes of enzymes in our cells?

44. Give the substrate and the type of reaction catalyzed for each of the following enzymes: a) maltase b) pyruvate carboxylase c) lipase

45. Explain the induced-fit model of enzyme action.

46. Why does an enzyme lose its activity when the pH not optimum?

47. Draw a graph of reaction rate vs. substrate concentration for an enzyme catalyzed reaction where the substrate concentration is not held constant, but instead the substrate gets used up during the experiment.

48. Explain why the activity of a competitive inhibitor can be reversed by increasing substrate concentration. Use a drawing to illustrate your answer.

49. Explain how zymogens are important in digestion.

50. What is an allosteric enzyme and how are they involved in feedback control?

51. What are the main functions of metal ions as cofactors?

52. Is the statement “water-soluble vitamins are coenzymes” valid? Explain.

53. Which vitamin is used to make each of the following coenzymes? a) FAD b) NAD

+ c) CoA

54. Vitamin A is a fat-soluble vitamin. a) What are the three forms of vitamin A? b) What are some dietary sources of vitamin A? c) Do plants actually contain vitamin A? Explain. d) What are the main functions of vitamin A?

55. What are the three main structural components of nucleic acids?

56. Is Thymine a purine or a pyrimidine?

57. Write out the full name for GDP.

58. Consider the following DNA sequence: a) Label the 5’ and 3’ ends.

AATCGC

b) Write the complementary DNA sequence. c) Write the mRNA sequence that would be transcribed from the DNA sequence. d) Write the amino acid sequence that would be translated from the mRNA sequence.

59. What is a replication fork?

60. What is an Okazaki fragment?

61. What are the three main types of RNA and what are their basic functions?

62. Where does processing of mRNA take place? Describe the process. Use drawings to illustrate your answer.

63. Describe how the lactose operon works.

64. Draw a schematic of the structure of tRNA, showing the binding sites for the amino acid and for the mRNA.

65. Why is a frame-shift mutation more likely to destroy protein function than a substitution mutation?

66. What is a genetic disease?

67. What is a plasmid?

68. What is recombinant DNA?

69. Where do restriction enzymes come from, and what do they do?

70. How could DNA fingerprinting be used to determine parenthood?

71. Describe how a viral infection occurs.

72. Nucleoside analogs, like AZT, which are used to treat HIV, have nasty side effects.

Give a possible explanation for why.

73. At what location does each of the following processes occur? a) glycolysis b) reduction of pyruvate c) oxidative phosphorylation

74. Where in the cell are ribosomes located?

75. Draw a diagram of a mitochondrion. Label the matrix, the intermembrane space, the outer membrane and the inner membrane.

76. Why is ATP considered a high-energy molecule?

77. The coenzyme NAD

+

is involved in many cellular reactions. a) What are the three main structural components of NAD

+

? b) Which of the three components is reduced during conversion to NADH? c) In what type of reactions does NAD

+

generally take part?

78. Describe what happens to starch in the mouth, before it is swallowed.

79. Where in the body are fructose and galactose converted to glucose?

80. Write the overall net reaction of glycolysis.

81. How is ATP involved in regulation of glycolysis?

82. What are the three pathways for pyruvate, and under what conditions do they occur?

83. What is the role of UDP in glycogenesis?

84. Which compounds activate glycogenolysis?

85. Write the overall reaction for gluconeogenesis.

86. What is the Cori cycle, and why is it important? Make a diagram showing the Cori cycle.

87. Write the overall reaction for the citric acid cycle.

88. Why is the citric acid cycle called a cycle?

89. State whether each of the following activates or inhibits the citric acid cycle:

a) ATP b) ADP c) NADH

90. What are the four main types of electron carriers in the electron transport chain?

91. Draw a diagram of an iron-sulfur cluster in its oxidized state. What happens to it when it accepts an electron?

92. In which complex of the electron transport chain is FADH

2

oxidized to FAD?

93. In which complex of the electorn transport chain is NADH oxidized to NAD

+

?

94. Draw a diagram of ATP synthase, showing the two subunits, F

0

an F

1

. Show where the protein crosses the intermitochondrial membrane and label the intermembrane space and the matrix. Show where the protons enter, where they leave and where the

ATP is synthesized.

95. Write the overall net reaction for the complete oxidation of glucose.

87. How are regulation of glucose levels and regulation of ATP levels related? Discuss in terms of the various cycles involved in glucose metabolism.

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