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Multiple Choice
What is unusual about the initiator tRNA in prokaryotes?
A
It carries unmodified methionine.
B
It carries valine instead of methionine.
C
It is not involved in protein synthesis.
D
It carries methionine that is formylated.
Verified step by step guidance
1
Understand that in protein synthesis, tRNA molecules are responsible for bringing amino acids to the ribosome, where proteins are assembled.
Recognize that the initiator tRNA is a special tRNA that starts the process of translation by binding to the start codon on the mRNA.
In prokaryotes, the initiator tRNA is unique because it carries a modified form of methionine, known as N-formylmethionine (fMet).
The formyl group is added to methionine after it is attached to the initiator tRNA, making it distinct from the methionine carried by other tRNAs.
This formylated methionine is crucial for the initiation of protein synthesis in prokaryotes, as it helps the ribosome recognize the start codon and begin translation.