Question

31. Which of the following describes the distribution of the polar and nonpolar portions of lipids in the lipid bilayer? A). Both polar heads are on the inside of the bilayer and both hydrophobic tails are on the outside of the bilayer. B). Both polar heads are on the outside of the bilayer and both hydrophobic tails are on the inside of the bilayer. C). Both the inside and outside of the bilayer consist of alternating polar heads and nonpolar tails. D). Some polar heads are on the inside of the bilayer and some are on the outside; the hydrophobic tails are similarly distributed.

33. Which describes the isoelectric point of an amino acid? A). The degree of ionization of the amino acid at pH 7. B). The pH at which there is no net charge for the amino acid. C). The pH at which the ionized form predominates. D). The pH at which the amino acid is present as the dipolar ion. CH2 – CONH2 

34. Asparagine (Asn) has an isoelectric point (pI) of 5.4, (H3N+ ¾CH¾COO- ). Select the correct Zwitterion structure of asparagine in a solution with a pH of 10. CH2 – CONH2 CH2– CONH2   A). H2N¾CH¾COO- B). H3N+ ¾CH¾COOH CH2– CONH2 CH2– CONH2   C). H2N¾CH¾COOH D). H3N+¾CH¾COO-

35. Which functional group is involved in linking together the amino acids of proteins? A). amine B). anhydride C). carbonyl D). carboxyl

36. Select the correct three-letter abbreviation for the order of amino acids in this tripeptide. O H O H O      H3N+  CH  C  N  CH  C  N  CHCO-    CH2OH CH3 H A). AlaGlySer B). GlySerAla C). SerAlaGly D). AlaSerGly

37. The secondary structure of proteins depends primarily on which property of amino acids? A). disulfide bonds B). hydrogen bonds C). amide bonds D). polar side chains

38. The beta-pleated sheet represents what level of protein structure? A). Primary B). Secondary C). Tertiary D). Quaternary

39. The following will denature proteins EXCEPT A). Agitation B). Acids and bases C). Heavy metal ions D). Freezing temperature

40. Which of the following is a structural protein? A). cellulose B). collagen C). hemoglobin D). insulin

41. In which of the following is the amino nitrogen also part of the side chain? A). cysteine B). glycine C). proline D). tryptophan

Answer 1