Question

Suppose a drug blocked the entry of tRNA molecules into the ribosome. What effect would this drug have on gene expression?

A. There would be no effect because RNA is not part of the product of gene expression (i.e., is not a polypeptide).
B. Transcription initiation would be blocked, so the cell would be unable to synthesize mRNA and polypeptides.
C. Translation elongation would be blocked, so the cell would be unable to synthesize polypeptides.
D. Translation termination would be blocked, so the ribosome would remain attached to the polypeptide.

Answer 1

Blocking tRNA entry into the ribosome would result in the blocking of translation elongation, preventing the cell from synthesizing polypeptides, as tRNA is essential for protein synthesis.

Step-by-step explanation:

If a drug blocked the entry of tRNA molecules into the ribosome, the effect on gene expression would be significant.

Answering the given options, the correct effect would be: C. Translation elongation would be blocked, so the cell would be unable to synthesize polypeptides. tRNA is essential for bringing amino acids to the ribosome, where they are added to the growing polypeptide chain during translation. Without tRNA entry, no amino acids can be added, thus halting protein synthesis. Tetracycline, as mentioned, would affect tRNA binding to the ribosome, specifically the A site, impeding the growth of the protein chain by preventing new amino acids from being added.