MCAT Question A Day - 3/31/13 - Answer!
Amino acids:
A. have one amino and one carboxylic acid group.
B. have low melting points.
C. exist as dipolar ions only.
D. have different ionic forms depending on the pH.
The correct answer is (D). Some amino acids contain a second acidic group (e.g., aspartic
acid) or a second basic group (e.g., lysine). Glycine is not optically active. In basic solution the
dibasic form of amino acids predominates, while in acidic solution the protonated form is in
highest concentration.
Want more questions? - Click here to check out our MCAT Question A Day archive
