Q.How many types of RNA polymerases exist in cells? Write their names and functions.

In eukaryotes, RNA polymerase I transcribes the major ribosomal RNAs (28S, 18S and 5.8S rRNA).

Eukaryotic cells have three distinct RNA polymerases, each transcribing a defined set of genes:

• RNA polymerase I transcribes the ribosomal RNAs — 28S, 18S, and 5.8S rRNA.
• RNA polymerase II transcribes the precursor of mRNA, i.e. heterogeneous nuclear RNA (hnRNA). …

DNA replication is catalysed by the enzyme DNA polymerase (DNA-dependent DNA polymerase).

During DNA replication, the enzyme DNA polymerase (specifically DNA-dependent DNA polymerase) catalyses the polymerisation of deoxyribonucleotides in the 5'→3' direction, using the parental strand as a template, to synthesise the new complementary daughter strand. It requires a primer (a short RNA segment made by the enzyme primase) to begin synthesis, and works alongside o …

During transcription, RNA polymerase synthesizes RNA by using ribonucleotide triphosphates as the building blocks, which pair with the exposed bases of the DNA template strand. The correct option is (C).

Ribosomal RNA (except 5S) is transcribed by RNA polymerase I in eukaryotes.

Eukaryotes have three nuclear RNA polymerases with a division of labour: RNA polymerase I transcribes the ribosomal RNAs (28S, 18S and 5.8S rRNA); RNA polymerase II transcribes the precursor of mRNA (hnRNA); and RNA polymerase III transcribes tRNA, 5S rRNA and small nuclear/snRNAs. Since the question asks specifically about ribosomal RNA transcription, the answe …

Eukaryotes use three RNA polymerases; Pol I makes the major rRNAs.

Eukaryotic cells have three distinct RNA polymerases, each transcribing a different set of RNAs: RNA polymerase I transcribes ribosomal RNA (rRNA), specifically the 28S, 18S and 5.8S rRNAs; RNA polymerase II transcribes the precursor of me …

In eukaryotes, three RNA polymerases have separate jobs; RNA Pol III makes tRNA, 5S rRNA, and other small RNAs.

Eukaryotic cells have three distinct nuclear RNA polymerases, each transcribing a different class of RNA:

• RNA Polymerase I — transcribes ribosomal RNA (rRNA), specifically 28S, 18S, and 5.8S rRNA.
• RNA Polymerase II — transcribes precursor of mRNA (heterogeneous nuclear RNA, hnRNA) as well as most snRNAs. …

In eukaryotic cells, the three main rRNA species (except 5S rRNA) are transcribed by RNA Polymerase I inside the nucleolus.

Eukaryotes have three main nuclear RNA polymerases, each dedicated to different classes of RNA:

• RNA Polymerase I transcribes the pre-rRNA that is processed into the 28S, 18S and 5.8S rRNAs (in the nucleolus).
• RNA Polymerase II transcribes heterogeneous nuclear RNA (hnRNA), the precursor of mRNA, as well as most snRNAs. …

RNA polymerase II transcribes the precursor of mRNA (heterogeneous nuclear RNA, hnRNA) in eukaryotes.

Concept. Unlike bacteria, which use a single RNA polymerase for all RNAs, eukaryotic cells possess three nuclear RNA polymerases, each dedicated to a specific class of RNA:

• RNA polymerase I → transcribes rRNAs (28S, 18S, 5.8S).
• RNA polymerase II → transcribes the precursor of mRNA, i.e. heterogeneous nuclear RNA (hnRNA).
• RNA polymerase III → transcribes tRNA, 5S rRNA and small nuclear RNAs (snRNAs). …

RNA polymerase catalyses transcription — it synthesises an RNA strand from a DNA template, joining ribonucleotides in the 5′→3′ direction.

Concept

Transcription is the copying of genetic information from DNA into RNA. The enzyme responsible is RNA polymerase, which reads the template strand of DNA and builds a complementary RNA strand.

Function

• RNA polymerase catalyses the polymerisation of ribonucleotides (using the DNA template) to make RNA, adding nucleotides only in the $5' \rightarrow 3'$ direction. …

Of the three eukaryotic RNA polymerases, RNA polymerase II is specifically responsible for transcribing hnRNA (the mRNA precursor).

Eukaryotic cells have three distinct RNA polymerases, each transcribing a different class of RNA:

• RNA polymerase I transcribes ribosomal RNA (rRNA), except 5S rRNA.
• RNA polymerase II transcribes heterogeneous nuclear RNA (HnRNA), the precursor that is processed (capping, tailing, splicing) into mature mRNA; it also transcribes some snRNAs. …

The three eukaryotic RNA polymerases divide the work: Pol III makes tRNA, 5S rRNA and snRNA.

Eukaryotes have three nuclear RNA polymerases with distinct roles:

• RNA Polymerase I — transcribes the large ribosomal RNAs (28S, 18S, 5.8S).
• RNA Polymerase II — transcribes precursor mRNA (hnRNA). …