MCAT Biochemistry Question 5: Answer and Explanation
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Question: 5
5. How many distinct tripeptides can be formed from one valine molecule, one alanine molecule, and one leucine molecule?
- A. 1
- B. 3
- C. 6
- D. 27
Correct Answer: C
Explanation:
There are three choices for the first amino acid, leaving two choices for the second, and one choice for the third. Multiplying those numbers gives us a total of 3 × 2 × 1 = 6 distinct tripeptides. (Using the one-letter codes for valine (V), alanine (A), and leucine (L), those six tripeptides are VAL, VLA, ALV, AVL, LVA, and LAV.)