Question

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Answer 1

Answer:

Option (C).

Explanation:

Instructions for the protein synthesis is present in DNA strand, which is transferred to mRNA by the process of transcription. During transcription, DNA sequence TCA will AGU, while DNA sequence TAA will give AUU codons in mRNA.

Codon AGU codes for serine, which is a hydrophilic amino acid, while codon AUU codes for isoleucine, which is a hydrophobic amino acid.

Due to this single-base substitution in DNA, the resulting mRNA will code for a different amino acid. As amino acid sequence of protein is responsible for its proper folding and functioning, the resulting protein will show an altered protein.

During protein folding, the hydrophilic amino acids are present at the surface of proteins, while hydrophobic amino acids are present at the center of proteins. So, the substituted amino acid, which is hydrophobic in nature will force its way to the core of the protein.

Thus, the correct answer is option (C).

Answer 2

The right answer is C.

When transcribing the TCA and TAA DNA, this gives respectively AGU and AUU.

AGU encodes a serine, which is a hydrophilic amino acid.

AUU encodes a hydrophobic amino acid which is isoleucine.

If we change the TCA codon to TAA, we will have serine change by isoleucine, so it is clear that the conformation of the protein will change.