GENETICS AND EVOLUTION
MOLECULAR BASIS OF INHERITANCE
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Question
[CLICK ON ANY CHOICE TO KNOW THE RIGHT ANSWER]
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the smaller ribosomal sub-unit
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the larger ribosomal sub-unit
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the whole ribosome
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no such specificity exists.
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Detailed explanation-1: -The first step of the initiation stage of translation is the binding of mRNA to the small ribosomal subunit through base pairing with appropriate sequences on rRNA.
Detailed explanation-2: -During translation initiation in eukaryotes, the small ribosomal subunit binds mRNA at the 5′-end and scans in the 5′ to 3′ direction to locate the initiation codon, form the 80S initiation complex and start the protein synthesis. This simple, yet intricate, process is guided by multiple initiation factors.
Detailed explanation-3: -tRNAs move through these sites (from A to P to E) as they deliver amino acids during translation. The ribosome is composed of a small and large subunit. The small subunit binds to an mRNA transcript and both subunits come together to provide three locations for tRNAs to bind (the A site, P site, and E site).
Detailed explanation-4: -Translation initiation is a complex process in which initiator tRNA, 40S, and 60S ribosomal subunits are assembled by eukaryotic initiation factors (eIFs) into an 80S ribosome at the initiation codon of mRNA.
Detailed explanation-5: -During initiation, the small ribosomal subunit binds to the start of the mRNA sequence. Then a transfer RNA (tRNA) molecule carrying the amino acid methionine binds to what is called the start codon of the mRNA sequence.