Exam 2B with 40 Questions - Introduction to Biochemistry | CHEM 3653, Exams of Chemistry

Download Exam 2B with 40 Questions - Introduction to Biochemistry | CHEM 3653 and more Exams Chemistry in PDF only on Docsity! CHEM 3653; Exam-2 December 6, 2013-B Page: Name: _______________________ OUID#:______________ 1 1. Propionyl-CoA can generate energy through the TCA cycle by converting it to a. succinate and acetyl-CoA. b. acetyl-CoA. c. succinyl-CoA. d. Fumarate and acetyl-CoA. 2. The carbon skeleton of leucine will ultimately enter the TCA cycle through a. only succinatyl-CoA. b. only acetyl-CoA. c. succinate and acetyl-CoA. d. Fumarate and acetyl-CoA. 3. Dietary fatty acids are transported from the intestines to the adipose tissue through the circulatory system via a. HDL. b. LDL. c. albumin. d. chylomicrons. 4. Ultimately, the carbon skeleton of all 20 amino acids can be used in a. gluconeogenesis. b. glycolysis. c. glycogen synthesis. d. the pentose phosphate pathway e. all of the above. 5. Phenylpyruvate is the product of the a. transamination of phenylalanine. b. deamination of pyruvate. c. oxidative decarboxylation of tyrosine. d. reduction of tryptophan. 6. Orotidylate is a. the purine that can ultimately be converted to adenylate and guanylate. b. the pyrimidine that can ultimately be converted to cytidylate and thymidylate. c. a urea cycle intermediate. d. a one carbon unit carrier. 7. For the insulin receptor to transduce the signal inside the cell, a. the G-alpha subunit needs to bind GTP to activate adenylate cyclase. b. the G-alpha subunit needs to bind GTP to activate phosphodiesterase. c. it needs to recruit a kinase to phosphorylate the cytoplasmic domain after dimerization. d. it needs to cross-phosphorylate the cytoplasmic domain after dimerization. 8. Losing the intrinsic GTPase activity of G protein will likely affect signal transduction by a. maintaining the signal amplification continuously inside the cell.<< b. not amplifying the signal inside the cell. c. phosphorylayting phenylalanine residues. d. converting cAMP to AMP eliminating the secondary messenger. 9. Nitrogen from deaminated amino acids is carried in the blood via a. alanine. b. oxaloacetate. c. aspartate. d. α-ketoglutarate. 10. If citrate lyase is deficient, a. fatty acid synthesis is inhibited. b. amino acid biosynthetic pathways are inhibited c. pyrimidine biosynthesis is activated d. the glyoxylate cycle is inactive e. the urea cycle is inhibited CHEM 3653; Exam-2 December 6, 2013-B Page: Name: _______________________ OUID#:______________ 2 11. CoA transferase is an essential enzyme in a. the TCA cycle through condensation with oxaloacetate. b. ketolysis through transferring CoA to acetoacetate. c. activating fatty acids with CoA for β-oxidation. d. activating malonate for fatty acid synthesis. 12. It takes two molecules of triglycerol to make a. one molecule of glucose. b. two molecules of fructose. c. two molecules of alanine. d. Both “a” and “b” are correct. e. Both “b” and “c” are correct. 13. One of the steps to terminate the signal in the β-adrenergic receptor transduction pathway is through the action of the a. serine/threonine phosphatase activity. b. protein kinase. c. tyrosine phosphatase. d. intrinsic GTPase activity in Gα subunit of the G protein. 14. One of the main causes for metabolic syndrome is a. over production of ketone bodies. b. a deficiency in mitochondrial biogenesis. c. the action of diacylglycerol as a result of over-nutrition of fatty acids. d. the lack of carnitine transferase enzymes. 15. Tetrahydrofolate is a one-carbon carrier of a. formyl. b. methyl. c. methylene. d. methenyl. e. All of the above. 16. The carbon skeleton of tyrosine will ultimately enter the TCA cycle through a. succinate and acetyl-CoA. b. only succintyl-CoA. c. only acetyl-CoA. d. fumarate and acetyl-CoA. 17. Fluorouracil kills cancer cells by inhibiting the synthesis of a. thymine. b. cytosine. c. uracil. d. adenine. e. guanine. 18. Glycerol produced from triglyceride mobilization in the adipose tissues a. can enter the glycolytic pathway through glyceraldehyde 3-phosphate or dihydroxyacetone phsophate. b. can enter the gluconeogenic pathway through glyceraldehyde 3-phosphate. c. can enter the gluconeogenic pathway through dihydroxyacetone phsophate. d. Both “a” and “c” are correct. e. all of the above. 19. Excess energy (ATP) in the cell stimulates a. nucleotide biosynthesis. b. beta-oxidation. c. glycolysis. d. both “b” and “c” are correct. e. both “a” and “c” are correct.