Question

The coding region of a gene is 102 nucleotides long, including both start and stop codons.which of the following would be the most likely effect of. a single nucleotide deletion at position 76 in the coding region

Answer 1

Answer:

There would be changes in only the last 8 amino acids.

Cheers!!!

Answer 2

The coding region of a gene is 102 nucleotides long, including both start and stop codons. Which of the following would be the most likely effect of a single nucleotide deletion at position 76 in the coding region?

a. There would be no effect on the polypeptide.

b. Only the active site would be affected.

c. The entire amino acid sequence of the polypeptide would change.

d. There would be changes in only the first 25 amino acids.

e. There would be changes in only the last 8 amino acids.

The correct option is e, "There would be changes in only the last 8 amino acids."

Given:

The coding region of a gene is 102 nucleotides long, and includes both start and stop codons.

To Find:

If the 76th nucleotide gets deleted then what will happen.

Solution:

We know, that a codon consists of 3 nucleotides and a codon gives one amino acid.

For 102 nucleotides, the number of codons will be, 102/3 = 34

But as the coding region includes a stop codon, so we need to subtract that as it won't code for any amino acid.

Thus the total number of coding codons becomes, 34-1 = 33

Thus 33 codons will give 33 amino acids normally.

Now, after the 76th nucleotide, there are 102-76 = 26 nucleotides.

If the 76th nucleotide gets deleted then the number will become 25 nucleotides

25 nucleotides will give 25/3 i.e, 8.33 ≈  8 codons which mean 8 amino acids.

But these last 8 amino acids will get changed as the sequence of the coding region is getting changed.

That means option e is correct.

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