In the genetic code, how many different codons can be made from the four RNA bases taken three at a time?
Answer and explanation
Correct answer: B.
- Step 1: Each of the three positions in a codon can hold any of the four bases A, U, G or C. Step 2. The number of codons is . **Answer: . Why not the others:** multiplies 4 by 3 instead of raising 4 to the power 3, is the number of amino acids the codons code for, and is , with the base and the power swapped.
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