Question

4. The figure below shows a stage in the translation process. or OLE (a) Name the above stage. (b) Name the molecules or parts labeled A to E. (c) Name the process of the formation of molecule B and the enzyme involved. (dy State the function of sequence o.

Answer 1

(1). Elongation stage : During elongation, ribosome travelling down the message, reading codons and bringing in the proper aminoacyl tRNA's to translate the message out to protein

(2).

(A). mRNA or messenger RNA : mRNA is single stranded RNA molecule that corresponds to the genetics sequence of a gene and is read by the ribosome in the process of producing a protein

(B). tRNA : a transfer RNA (tRNA) molecule is used in translation and consists of a single RNA strand that is only about 80 nucleotide long,containing an anticodon on the other end

(C). The elongating amino acid chain : where amino acids are linked together by peptide bond ( Leu means, amino acid Leucine)

(D). Stop codon or termination codon : That signals a termination of translation into protein

(E). The larger subunit of ribosome : ribosome is a complex molecule made of ribosomal RNA molecules and proteins that form a factory for protein synthesis in cell

(3). tRNA methylation : The methylation of tRNA is a post transcriptional modification which is achieved by specific enzyme, the tRNA methylases, with the S adenosylmethionine as a methyl donor

(4). UAA is a stop codon : In the genetic code, a stop codon is a nucleotide triplet within messenger RNA that signals a termination of translation into proteins.

- The stop codon termination factor doesn't have an amino acid on it, so when the aminoacyl transfer reaction take place to move the peptide chain off the tRNA and onto the next tRNA (termination factor), the peptide chain gets dropped and the peptide is now free of the ribosome and is able to fold up into the functional protein