Question

transcription in eukaryotes

Answer 1

In Eukaryotes

There are at least three RNA polymerase in the nucleus.

The primary transcript hnRNA ( Heterogenous Nuclear RNA ) contains two types of segments the non coding introns and coding exons.

The primary eukaryotic mRNA transcript is non functional it undergoes three types of processing;

• 1) SPLICING : Where the introns are removed and exons are joined in a definite manner.

• 2)CAPPING: An unusual nucleotide methyl guanosine triphosphate is added to the 5’ end of the hnRNA .

• 3) TAILING: Adenylate residues are added (polyadenylation) at 3’ end of hn RNA

Answer 2

Answer :-

Transcription in eukaryotes -

• The process of transcription in eukaryotes is more complex that that of prokaryotic transcription.

• Transcription in eukaryotes occurs inside the nucleus of the cell and the two types of semi-autonomous cell organelles ( Plastics and Mitochondria).

• This process takes place in the G1 and G2 phases of the cell cycle.

• Eukaryotes have three different types of RNA polymerases, namely- RNA polymerase I, RNA polymerase II and RNA polymerase III.

• The RNA polymerase I is responsible for the transcription of rRNAs (28s, 18s, and 5.8s).

• The RNA polymerase II is responsible for the transcription of the precursor of mRNA, and the heterogeneous nuclear RNA (hnRNA).

• The RNA polymerase III is responsible for the transcription of tRNA, 5SrRNA and snRNAs (small nuclear RNAs).