Question

question 16 of 20 :
select the best answer for the question.

1. how might a gene mutation be silent, with no observable effect on a cell or an organism?

a. many amino acids are encoded by multiple codons. a gene mutation that encodes the same amino acid would have no observable effect on
the cell or the organism.

b. many proteins are superfluous to the function of a cell. a gene mutation in a gene that encodes an unnecessary protein would have no
observable effect on the cell or the organism.

c. codons are complementary to anticodons in trna. a gene mutation that changes a codon to its anticodon would have no observable effect
on the cell or the organism.

d. several codons are stop codons. a gene mutation that inserts a stop codon when only a few amino acids remain in the peptide sequence
would have no observable effect on the cell or the organism.

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Explanation:

To determine the correct answer, we analyze each option:

• Option A: The genetic code is degenerate, meaning multiple codons can code for the same amino acid (e.g., UUU and UUC both code for phenylalanine). If a mutation changes a codon to another that codes for the same amino acid, the resulting protein remains unchanged, so there's no observable effect. This is consistent with the concept of silent mutations.
• Option B: Most proteins in a cell have important functions; the idea of "superfluous" proteins is incorrect. A mutation in a gene for any protein (even if misperceived as unnecessary) could still have effects if the protein has a role, so this is wrong.
• Option C: Changing a codon to its anticodon would likely change the amino acid sequence (since codons and anticodons are complementary but code for different things in terms of translation), leading to a different protein and observable effects. So this is incorrect.
• Option D: Inserting a stop codon prematurely (even with a few amino acids left) would truncate the protein, likely altering its function and causing observable effects. Thus, this is wrong.

Answer:

A. Many amino acids are encoded by multiple codons. A gene mutation that encodes the same amino acid would have no observable effect on the cell or the organism.