Question

During initiation of translation in both eukaryotes and prokaryotes the ________ binds before the ________.

A) large ribosomal subunit; small ribosomal subunit
B) small ribosomal subunit; large ribosomal subunit
C) EF-Tu; tRNA
D) EF-G; EF-Tu
E) ribosomes; initiation factors

Answer 1

In both eukaryotes and prokaryotes, the small ribosomal subunit binds before the large ribosomal subunit during the initiation of translation.

Step-by-step explanation:

In both eukaryotes and prokaryotes, the small ribosomal subunit binds before the large ribosomal subunit during initiation of translation.

In eukaryotes, the small ribosomal subunit binds to the mRNA and scans along until it identifies the start codon. Then, the initiator tRNA hydrogen bonds to the start codon, and finally, the large ribosomal subunit binds.

In prokaryotes, the start codon codes for N-formyl-methionine carried by a special initiator tRNA. The small ribosomal subunit binds to the mRNA with the help of initiation factors, and the initiator tRNA binds to the start codon, forming the initiation complex. Then, the large ribosomal subunit binds to the initiation complex, completing the initiation of translation.