NEET BIOLOGY

Detailed explanation-1: -RNA Polymerase I, also known as Pol I, is an enzyme that transcribes ribosomal RNA. It is composed of 14 subunits and weighs around 590 kDa. It transcribes the subunits of rRNA except for the 5S rRNA subunit. The transcription by Pol I accounts for about 50% of the total transcription in a cell.

Detailed explanation-2: -The task of transcribing nuclear genes is shared between three RNA polymerases in eukaryotes: RNA polymerase (pol) I synthesises the large rRNA, pol II synthesises mRNA and pol III synthesises tRNA and 5S rRNA.

Detailed explanation-3: -Eukaryotic 5S rRNA is synthesized by RNA polymerase III.

Detailed explanation-4: -RNA polymerase 1 (also known as Pol I) is, in higher eukaryotes, the polymerase that only transcribes ribosomal RNA (but not 5S rRNA, which is synthesized by RNA polymerase III), a type of RNA that accounts for over 50% of the total RNA synthesized in a cell.

Detailed explanation-5: -The 5.8S, 18S, and 28S rRNA are transcribed by RNA polymerase-I while 5S rRNA is transcribed by RNA polymerase-III.