Question

multiple choice question
after the $nh_2$ group is removed from an amino acid, the remainder of the molecule is called a(n) ______ acid.

• lactic
• amino
• pyruvic
• keto

Explanation:

To solve this, we recall biochemical concepts: when the amino group ($\ce{NH2}$) is removed from an amino acid, the remaining molecule is a keto acid. Lactic acid is from lactic fermentation, amino acid still has $\ce{NH2}$, pyruvic acid is a different intermediate. So the correct answer relates to the structure after deamination (removal of $\ce{NH2}$), leading to keto acid.

Answer:

D. keto