Question

What is necessary for a eukaryotic RNA to be recognized and bound by the small subunit of the ribosome?

a) Formation of the pre-initiation complex before ribosome binding.
b) Formation of the initiation complex before ribosome binding.
c) Sufficiently large 5' UTR for ribosome scanning.
d) Presence of 5' methyl-G cap on the mRNA.
e) Presence of an AUG start codon near the 5' end of the mRNA.

Answer 1

The presence of an AUG start codon near the 5' end of the mRNA is necessary for a eukaryotic RNA to be recognized and bound by the small subunit of the ribosome. Hence the correct answer is option E

Step-by-step explanation:

The necessary requirement for a eukaryotic RNA to be recognized and bound by the small subunit of the ribosome is the presence of an AUG start codon near the 5' end of the mRNA. Instead of binding to the mRNA at the Shine-Dalgarno sequence like in prokaryotes, the eukaryotic initiation complex recognizes the 5' cap of the eukaryotic mRNA. The small subunit tracks along the mRNA in the 5' to 3' direction until it identifies the AUG start codon, at which point the large subunit binds to the complex.

Hence the correct answer is option E