Use the mutation lab to answer the question below. Which of the following substi

Question

Use the mutation lab to answer the question below. Which of the following substitution mutations most substantially impacts the resulting polypeptide? O changing C to A within the DNA segment TGC in the middle of the DNA strand O changing A to C within the DNA segment ATC near the 5' end of the template DNA strand O changing G to C within the DNA segment GTA near the 3 end of the DNA strand Why did this substitution mutation have the greatest impact? O O O O A stop codon was changed to one encoding an amino acid, elongating the polypeptide. It caused a frameshift mutation, impacting all the downstream amino acids in the polypeptide It changed the start codon, so no polypeptide was synthesized from the resulting mRNA. A codon encoding an amino acid was changed to a stop codon, truncating the polypeptide.

Explanation / Answer

TGC make ACG thr amino acid.

TGA make ACU mRNA that codes for Thr amino acid.

ATC make UAG at mRNA at 5’ end that encode for termination codon. Hence it will terminate the polypeptide prematurely.

GTA make CAU that code for His.

CTA make GAU that code for asp

Slightly change in amino acid hardly makes any major difference. Here second answer is correct.

If termination codon is changed than it is possible that extended polypeptide can perform their function.

A frame shift mutation will make protein synthesize and may be it will perform some function.

If initiation codon is absent then polypeptide will not synthesize.

Truncated polypeptide may also work some time.

Here third answer is correct

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