Natural proteins are composed primarily of 20 α-amino acids. Which one of the following statements is true for any of these amino acids in a solution of pH 1.5?
A. Only the amino group is ionized
B. Only the carboxylic acid group is ionized
C. Both amino and carboxylic acid groups are ionized
D. Both amino and carboxylic add groups are neutral
Answer: Option A
Which one of the following is INCORRECT about protein structures?
A. A protein fold is stabilized by favorable noncovalent interactions
B. All parts of a fold can be classified as helices, strands or turns
C. Two non-covalent atoms cannot be closer than the sum of their van der Waals radii
D. The peptide bond is nearly planar
Which one of the following amino acids has three ionizable groups?
A. Glycine
B. Leucine
C. Valine
D. Lysine
During lactic acid fermentation, net yield of ATP and NADH per mole of glucose is
A. 2 ATP and 2 NADH
B. 2 ATP and 0 NADH
C. 4 ATP and 2 NADH
D. 4 ATP and 0 NADH
The reactions leading to the formation of amino acids from the TCA cycle intermediates are
A. Carboxylation
B. Isomerization
C. Transamination
D. Decarboxylation
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