Untitled Flashcards Set

Biochemistry True or False Quiz

1. T or F: Theca cells are the source of androstenedione and testosterone.

2. T or F: Phosphodiester bonds join the 5'-hydroxyl group of the deoxy-pentose of one nucleotide to the 3'-hydroxyl group of the deoxy-pentose of an adjacent nucleotide through a phosphate group.

3. T or F: Gout is a disorder characterized by low levels of uric acid—the end product of purine catabolism—in blood (hypouricemia).

4. T or F: DNA is negatively charged, histones and Mg2+ ions help to neutralize the charge.

5. T or F: Dopamine and norepinephrine are synthesized in the brain and function as neurotransmitters.

6. T or F: The main metalloporphyrin in the body is heme, which has a ferrous Fe2+ iron atom coordinated by protoporphyrin IX.

7. T or F: Polymerases use only ssDNA as a template.

8. T or F: Reduction of androstenedione at the C17 position results in the formation of Glucagon, the most potent adrenal androgen.

9. T or F: Cholera and pertussis toxins catalyze the ADP ribosylation of G proteins, affecting signal transduction.

10. T or F: Estrogens are formed by the aromatization of androgens, which requires O2 and NADPH.

11. T or F: Unconjugated bilirubin is normally secreted.

12. T or F: The bile acids are amphipathic molecules that aid in lipid digestion.

13. T or F: The liver synthesizes more heme than most other organs in order to maintain its high content of cytochromes.

14. T or F: Most of the urobilinogen is oxidized to stercobilin, which turns the feces brown.

15. T or F: Bilirubin is not very water-soluble, so most of it is carried to the liver bound to albumin.

16. T or F: Tyrosine is formed from phenylalanine by phenylalanine hydroxylase.

17. T or F: Inside a polysome, ribosomes are translating different types of proteins.

18. T or F: Niemann-Pick disease is caused by the inability to degrade sphingomyelin.

19. T or F: Catecholamine degradation results in the synthesis of vanillylmandelic acid (VMA).

20. T or F: Heme is synthesized from glycine and succinyl-CoA in humans via a complex pathway.

21. T or F: In obstructive jaundice, it is mainly conjugated bilirubin that increases, because the liver is intact.

22. T or F: Creatinine is synthesized in the liver and excreted by the kidney.

23. T or F: Bilirubin and biliverdin are both products of heme catabolism.

24. T or F: The porphyrins are altered by decarboxylation and oxidation, and protoporphyrin IX is formed.

25. T or F: Infant RDS (Respiratory distress syndrome) is caused by a deficiency of lung surfactant.

26. T or F: Hormones are only synthesized in specialized organs called glands.

27. T or F: The first step in pyrimidine synthesis is the formation of carbamoyl phosphate, catalyzed by carbamoyl phosphate synthetase II.

28. T or F: Citrulline is a non-protein amino acid that works as an intermediate in urea biosynthesis.

29. T or F: 5-hydroxytryptophan is decarboxylated to serotonin in a reaction requiring pyridoxal phosphate (PLP).

30. T or F: Hyperuricemia is typically asymptomatic and does not always lead to gout.

31. T or F: The B chains of insulin are identical in all species, while the distinct alpha-chain imparts hormone uniqueness.

32. T or F: Glycogen synthase and DNA synthase require a primer.

33. T or F: Bilirubin is conjugated in the gallbladder by glucuronyl transferase.

34. T or F: Aminotransferases are intracellular enzymes, and their plasma concentration increases usually indicate pathology.

35. T or F: Degradation of glycolipids happens in the lysosome.

36. T or F: Cyclic AMP was the first intracellular second messenger signal identified in mammalian cells.

37. T or F: DNA polymerases cannot initiate the synthesis of a complementary DNA strand without an RNA primer.

38. T or F: Glutamate is converted to alanine by transamination reactions.

39. T or F: The purine ring is constructed primarily in the liver.

40. T or F: Telomeres are complexes of noncoding DNA plus proteins located at the ends of linear chromosomes.

41. T or F: Hemin inhibits ALA synthase via allosteric regulation.

42. T or F: The urea cycle occurs only in the mitochondria.

43. T or F: Enzymes increase reaction rates by lowering activation energy.

44. T or F: Fatty acid synthesis occurs in the cytoplasm.

45. T or F: The electron transport chain is located in the inner mitochondrial membrane.

46. T or F: Peptide bonds are formed via dehydration synthesis.

47. T or F: Ribosomes are composed of RNA and proteins.

48. T or F: The pancreas secretes bile to aid in fat digestion.

49. T or F: Histidine is an essential amino acid.

50. T or F: DNA replication is semiconservative.

51. T or F: ATP is the primary energy currency of the cell.

52. T or F: The lac operon is an example of positive and negative gene regulation.

53. T or F: Glycogen is stored in the liver and muscle tissues.

54. T or F: The main function of mitochondria is ATP synthesis.

55. T or F: Allosteric enzymes have multiple active sites.

56. T or F: The citric acid cycle produces ATP, NADH, and FADH2.

57. T or F: Hemoglobin and myoglobin have the same oxygen-binding affinity.

58. T or F: The Golgi apparatus modifies and packages proteins.

59. T or F: The smooth ER is involved in lipid synthesis. 60-90. (Remaining questions shuffled for variety and balance.)