Question

Generally, in eukaryotic cells the average length of a transcription unit along a DNA molecule is about 8,000 nucleotides, so the RNA product of the transcription is also that long. But it only takes about 1200 nucleotides from the above RNA product to translate average sized polypeptide of 400 Amino acids. (a) Name this RNA product transcribed from the DNA that subsequently translates into a polypeptide of 400 amino acids. Mention the enzyme responsible for transcribing this type of RNA from the DNA. (b) Name and explain the process the RNA molecule transcribed from 8000 nucleotide long DNA undergoes to be able to translate a polypeptide of 400 amino acids. (c) Write the number of RNA polymerases involved in the transcription of DNA in a prokaryote and eukaryotes.

Accepted Answer

(a) • hnRNA/ heterogeneous nuclear RNA • RNA polymerase II (b) hnRNA undergo capping at 5’ end (methyl guanosine triphosphate/mGppp), and tailing at 3’ end (with poly A tail or adenylate residue), further splicing is carried out, where non coding sequences or introns are removed and coding sequence or exons are joined together/ diagrammatic representation with given markers can also be considered. (c) • In prokaryotes - 1 • In eukaryotes-3

Marking-scheme solution

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Generally, in eukaryotic cells the average length of a transcription unit along a DNA molecule is about 8,000 nucleotides, so the RNA product of the…

Marking-scheme solution

More from Molecular Basis of Inheritance