A normal polypeptide includes the following sequence of amino acids (Note:Each amino acid is named by a three-letter abbreviation.)

Iso-Leu-Pro-Val-His-Ser-Thr-Met

After a mutation, the amino acid sequence becomes the following:

Iso-Leu-Pro-Val-Tyr-Arg-Iso-Gly

Which of the following changes to a nitrogenous base in mRNA is most likely to have occured?

a. A cytosine (C) was replaced with uracil (U).

b. A uracil (U) was replaced with a thymine (T)

c. An adenine (A) was removed and not replaced

d. The codon ACU was removed and not replaced

Question

Alice Guerrero

Biology

17 November, 12:40

A normal polypeptide includes the following sequence of amino acids (Note:Each amino acid is named by a three-letter abbreviation.)

Iso-Leu-Pro-Val-His-Ser-Thr-Met

After a mutation, the amino acid sequence becomes the following:

Iso-Leu-Pro-Val-Tyr-Arg-Iso-Gly

Which of the following changes to a nitrogenous base in mRNA is most likely to have occured?

a. A cytosine (C) was replaced with uracil (U).

b. A uracil (U) was replaced with a thymine (T)

c. An adenine (A) was removed and not replaced

d. The codon ACU was removed and not replaced

+5

Answers (1)

Know the Answer?

Shiner · Answer 1

C

Explanation:

The mutation seen is most likely due to a frameshift mutation. A nucleotide was added or removed without replacement. This shifted the codon reading sequence by one nucleotide. Therefore the codon downstream of the mutation will code for different amino acids.