Question

You know that there are twenty different types of naturally occurring amino acids and four different types of bases in the DNA. A combination of 3 such bases codes for a specific amino acid. If instead there are 96 different amino acids and 12 different bases in the DNA, then the minimum number of combination of bases required to form a codon is:

• A. 6
• B. 3
• C. 2
• D. 4

Hint:

To determine the minimum number of bases per codon needed to encode a given number of amino acids, use the formula \( \text{Number of combinations} = (\text{Number of bases})^{\text{Number of bases per codon}} \), and solve for \( n \).

Answer 1

The Correct Option is C

To determine the minimum number of base combinations for 96 distinct amino acids, we use the formula: Number of combinations = (Number of bases)^(Number of bases per codon). With 12 base types in DNA, we need to find the smallest 'n' such that \( 12^n \geq 96 \). Calculating powers of 12: \( 12^1 = 12 \) and \( 12^2 = 144 \). Since \( 12^2 = 144 \) is the first power greater than or equal to 96, the minimum number of bases per codon is 2. Thus, the correct answer is \( \boxed{2} \). Option (A): Incorrect. \( 12^6 \) is excessive.
Option (B): Incorrect. \( 12^3 \) is more than required.
Option (C): Correct. \( 12^2 = 144 \) is the minimum required to exceed 96 combinations.
Option (D): Incorrect. While 4 bases per codon generate many combinations, 2 is the minimum.