Question

Which of the following is true of protein synthesis ONLY in prokaryotes?

• A. Translation and transcription are coupled
• B. The codon AUG codes for the start signal
• C. The tRNA anticodon can bind to two or more different codons
• D. The functional ribosomes contain two subunits constructed of proteins and RNA

Hint:

Prokaryotes can translate mRNA even before transcription completes — a key distinguishing feature.

Answer 1

The Correct Option is A

Step 1: Understand prokaryotic gene expression.
In prokaryotes, the absence of a nucleus allows transcription and translation to occur simultaneously in the cytoplasm. This coupling is unique to prokaryotes.
Step 2: Analyze the options.
(A) Correct — transcription-translation coupling is exclusive to prokaryotes.
(B) Incorrect — AUG is a start codon in both prokaryotes and eukaryotes.
(C) Incorrect — wobble base pairing occurs in both groups.
(D) Incorrect — both prokaryotic and eukaryotic ribosomes have two subunits made of rRNA and proteins.
Step 3: Conclusion.
Thus, only option (A) is exclusively true for prokaryotic protein synthesis.