41. Indicate which of these common amino acids in proteins can release a proton from their lateral chain.
a. Alanine, lysine
b. Lysine, glutamate
c. Serine, threonine
d. Aspartate, leucine
42. An enzyme promotes a chemical reaction by:
a. Changing the direction of the enzymatic reaction
b. Changing the free energy of the reaction
c. It binds irreversibly to the substrate
d. Lowering the energy of activation
43. Which of the following best describes the arrangement of amino acid side chains in an alpha-helix?
a. The side chains (R) point inward toward the center of the helix.
b. The side chains (R) point outward away from the helical axis.
c. The side chains (R) point toward the C-terminal end of the helix.
d. The side chains (R) point toward the N-terminal end of the helix.
44. Select the correct answer about proteins:
a. Conjugated proteins are the ones that contain more than two polypeptide chains.
b. In globular protein, Trp and Phe residues are located on the surface of the protein.
c. Fibrous proteins are highly soluble in water.
d. Simple proteins are the ones that contain amino acids in their structure.
45. Which of the following compounds is an energy-rich compound?
a. Pyruvate
b. Phosphoenolpyruvate
c. Dihydroxyacetone phosphate
d. Glyceraldehyde 3-phosphate