Question

What sequence of amino acids will the mRNA now code for if a mutation occurs in the DNA, changing the fourth base (counting from the 5' end) of the messenger RNA from G to A?

Answer 1

If a mutation occurs in the DNA, changing the fourth base of the mRNA from G to A, it will lead to a different sequence of amino acids being coded. The mutation changes the reading frame, resulting in a completely different amino acid sequence.

Step-by-step explanation:

If a mutation occurs in the DNA, changing the fourth base of the mRNA from G to A, it will lead to a different sequence of amino acids being coded. Let's look at an example to illustrate this. Original mRNA sequence: AUG-AAA-UAC-GGC-U. Mutated mRNA sequence: AUG-AAA-UAC-GGC-U. The mutation changes the reading frame, resulting in a completely different amino acid sequence. In the mutated mRNA, the AUG start codon now codes for methionine, AUA codes for isoleucine, and CCG codes for proline, among others.