Question

question 1 of 10
why does a frameshift mutation usually cause more defects during protein
synthesis than a point mutation?
a. frameshift mutations are silent mutations.
b. frameshift mutations can affect many amino acids.
c. frameshift mutations affect the whole chromosome.
d. frameshift mutations only occur during translation.

Explanation:

• Point mutations change a single nucleotide. They may result in a silent mutation (no change in amino acid), missense (one amino acid change), or nonsense (premature stop).
• Frameshift mutations (insertion or deletion of nucleotides not in multiples of three) shift the reading frame. This affects all subsequent codons (groups of three nucleotides) in the mRNA. Since each codon codes for an amino acid (or a stop signal), a frameshift mutation can change many amino acids in the resulting protein, often leading to a non - functional protein. For example, if the original mRNA sequence is \(AUG\ GCU\ UUA\ CCC\) (coding for Met - Ala - Leu - Pro) and there is a deletion of one nucleotide in the \(GCU\) codon, the reading frame shifts. The new sequence might be \(AUG\ CUU\ ACC\ C\cdots\) (coding for Met - Leu - Thr and then a frameshift - induced incorrect sequence). So, frameshift mutations usually cause more defects during protein synthesis as they can affect many amino acids compared to point mutations which have more limited effects.

Answer:

C. Frameshift mutations can affect many amino acids.