Multiple Choice
In the context of the genetic code, what is the relationship between DNA codons and proteins?
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11. Translation
The Genetic Code
Multiple Choice
Most organisms on Earth use essentially the same genetic code to translate mRNA codons into amino acids. How many distinct genetic codes are used by life on Earth?
A
Sixty-four (one genetic code for each codon)
B
Four (one for each nucleotide: A, U/T, G, and C)
C
Twenty (one genetic code for each amino acid)
D
One (a nearly universal genetic code, with a few minor variant codes)
Verified step by step guidance1
Understand that the genetic code refers to the set of rules by which the sequence of nucleotides in mRNA is translated into amino acids during protein synthesis.
Recognize that there are 64 possible codons (combinations of three nucleotides) because there are 4 nucleotides (A, U, G, C) and codons are triplets, so \$4^3 = 64$.
Note that although there are 64 codons, these codons map to only 20 standard amino acids plus stop signals, meaning the genetic code is redundant but specific.
Realize that almost all known organisms use the same genetic code, called the 'universal genetic code,' with only a few minor variations found in some mitochondria and certain microorganisms.
Conclude that despite the number of codons and amino acids, life on Earth predominantly uses one nearly universal genetic code.
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