Question

A scientist introduces a mutation that makes the 60S ribosomal subunit nonfunctional in a human cell line. What would be the predicted effect on translation?

a) Initiation of translation would be impaired.
b) Elongation of translation would be impaired.
c) Termination of translation would be impaired.
d) Transcription would be affected.

Answer 1

Mutation in the 60S ribosomal subunit impedes the elongation phase of translation, preventing amino acids from being added to the polypeptide chain, thereby stalling translation.

Step-by-step explanation:

When the 60S ribosomal subunit of a human cell line is rendered nonfunctional due to a mutation, it dramatically affects the process of translation. The 60S subunit is a part of the larger ribosomal subunit in eukaryotes, which is essential for the elongation phase of protein synthesis. During this phase, amino acids are added one by one to the growing polypeptide chain. Without a functional 60S subunit, the ribosome cannot move along the mRNA strand, and thus, the addition of amino acids to a nascent protein cannot occur. This effectively stalls the translation process after the initiation complex has been formed. Therefore, the predicted effect on translation would be that elongation would be impaired, not just initiation.