ACS BIOCHEMISTRY 360 FINAL EXAM REVIEW KEY 2023.WITH 100% CORRECT ANSWERS AND EXPLANATIONS
1. Which of the following statements about collagen is
... [Show More] correct?
a) Collagen contains a high proportion of hydroxylated proline residues.
b) Collagen is a globular, intracellular protein.
c) Post-translational modification of collagen involves vitamin A.
d) The structure of collagen consists of a superhelix of three α helices twisted together
Explanation – collagen has α chains, NOT helices. Each of the polypeptides in the triple superhelix of procollagen is an unusual left-handed helix not the right-handed α helix seen in globular proteins. However, the three polypeptides are twisted around each other in a right- handed manner to form the triple helix. All α helices are right-handed and get broken from high amounts of proline, hydroxylated proline, and glycine; but, these triplets of amino acids strength collagen. Glycine-X-Y.
2. Which of the following polypeptides is expected to be a globular protein?
a) KFSCCKDVVDG
b) IPVDSEDKHWY
c) AFSCKHEDGML
d) RDGLIVFYWSC
e) DEHRKICLRRG
Explanation – Utilize the one letter codes for all amino acids and know their charge and polarity. Globular proteins are usually seen in aqueous environments and will fold to have nonpolar amino acids on its interior. Based on that information, the polypeptide needs to have outside amino acids that are charged or polar while the interior will have nonpolar/hydrophobic amino acids. D is correct because (RDGLIVFYWSC) arginine, aspartate, serine, and cysteine are polar/charged.
3. Select answers that match with the amino acid. Some answers will have more than one answer.
1. acidic side chain
2. non-chiral amino acid
3. basic side chain
4. side chain can be modified by adding phosphates
5. involved in disulfide cross links
6. often found in the turns of proteins
7. is converted to tyrosine by hydroxylation leucine 11
aspartate 1
serine 4, 12
lysine 3, 8, 9
phenylalanine 7, 13
asparagine 9, 12
glycine 2, 6
tyrosine 4, 12, 13 [Show Less]