Question

question 11
which of the following best describes a silent mutation?
a mutation that does not change the amino acid sequence of a protein
a mutation that does not cause the cell to die
a mutation that changes one amino acid in a protein to another amino acid
a mutation that introduces a premature stop codon
a mutation that shifts the reading frame of the genetic code

question 12
why are frameshift mutations generally more harmful than other point mutations?
they always cause the cell to die
they change the reading frame of the codon sequence which may change many amino acids in a protein resulting in a non - functional protein
they always result in a silent mutation
they do not ever affect the function of a protein
they are never harmful to the cell as the sequence in which codons are read is not important in protein production

Explanation:

• Question 11:
• A silent mutation is a type of point mutation. Due to the degeneracy of the genetic code (multiple codons can code for the same amino acid), a change in a single nucleotide (base - pair substitution) can occur in the DNA sequence. When this DNA is transcribed into mRNA and then translated, the resulting amino acid sequence of the protein remains unchanged.
• Option B is incorrect because many non - silent mutations also do not cause cell death. Option C describes a missense mutation. Option D describes a nonsense mutation (if a stop codon is introduced prematurely). Option E describes a frameshift mutation.
• Question 12:
• Frameshift mutations (insertions or deletions of nucleotides that are not in multiples of three) shift the reading frame of the mRNA. Since the genetic code is read in triplets (codons), this shift changes the reading frame for all subsequent codons. As a result, a large number of amino acids in the protein are likely to be altered, often leading to a non - functional protein.
• Option A is incorrect because not all frameshift mutations cause cell death. Option C is wrong as frameshift mutations are not silent mutations. Option D is incorrect because frameshift mutations usually do affect protein function. Option E is wrong because the reading frame of codons is crucial for proper protein production.

Answer:

• Question 11: A. A mutation that does not change the amino acid sequence of a protein
• Question 12: They change the reading frame of the codon sequence which may change many amino acids in a protein resulting in a non - functional protein