Question

explain the initiation process of protein synthesis?(4 mark)​

Answer 1

Answer:

Explanation:

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. The start codon in all mRNA molecules has the sequence AUG and codes for methionine.

Answer 2

Answer:

Hi friends,

The protein synthetic machinery must select the appropriate starting points for mRNA reading and peptide bond formation. AUG is usually used as the starting codon, and essentially all proteins begin with a methionine. AUG is also the codon for methionine that occurs in the interior of a protein as well, so there must be a mechanism to distinguish between the two types of methionine codons.

The steps of initiation occur on the isolated small subunit (30S) of the prokaryotic ribosome. Ribosomes contain two subunits, a 30S and 50S subunit, which associate to form a 70S particle. (The S values refer to the rate at which each component sediments in the ultracentrifuge; they don't always add up.) In general, the 30S subunit is mostly involved in the decoding and tRNA‐mRNA interaction process, while the 50S subunit is involved in actual peptide bond synthesis. Ribosomal subunits are dissociated prior to the initiation reaction.

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