Question Video: Understanding the Term “Degenerate” When Applied to the Genetic Code | Nagwa Question Video: Understanding the Term “Degenerate” When Applied to the Genetic Code | Nagwa

Question Video: Understanding the Term “Degenerate” When Applied to the Genetic Code Biology • Third Year of Secondary School

The amino acid alanine can be coded for by the codons GCU, GCC, GCA, or GCG. What feature of the genetic code is this an example of?

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Video Transcript

The amino acid alanine can be coded for by the codons GCU, GCC, GCA, or GCG. What feature of the genetic code is this an example of? (A) It is universal. (B) It is nonoverlapping. (C) It is specific for each organism. (D) It is degenerate. (E) It contains no repeated codons.

In order for a gene in DNA to be converted into a protein, it needs to go through two steps. First, the DNA sequence is converted into mRNA during a process called transcription. Then the sequence in mRNA is converted into a sequence of amino acids to form the protein. Let’s look at how a sequence of mRNA can be translated into amino acids.

A group of three nucleotides in mRNA is called a codon. In this nine-nucleotide sequence of mRNA, there’s three codons. The specific sequence in a codon corresponds to a specific amino acid. The sequence GCU corresponds to the amino acid alanine. How these codons are converted into amino acids is given by the genetic code. Here, we can see a codon wheel that gives the different combinations of nucleotides in codons and the corresponding amino acid.

The codon GCU corresponds to the amino acid alanine. We can also see that the codons GCC, GCA, and GCG also correspond to the amino acid alanine. Four different codons can all code for the same amino acid. The genetic code is redundant, or degenerate, meaning that more than one codon can code for a specific amino acid.

Therefore, the correct answer is answer choice (D). It is degenerate.

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