MCAT Organic Chemistry Question 136: Answer and Explanation

Home > MCAT Test > MCAT organic chemistry practice tests

Test Information

Question: 136

1. Which of the following amino acids does not have an L-enantiomer?

  • A. Cysteine
  • B. Threonine
  • C. Glutamic acid
  • D. Glycine

Correct Answer: D

Explanation:

Glycine’s R group is a hydrogen atom; this amino acid is therefore achiral because the central carbon is not bound to four different substituents. The other amino acids are all chiral and therefore have both L- and D-enantiomers.

Previous       Next