Question

Name the enzymes responsible for transcription of tRNA and hnRNA from template DNA strands.

Answer 1

Transcription is a way of copying by the data present in a strand of DNA into a new molecule of messenger RNA. Generally, the genetic material is stored safely and stably in the DNA in the nuclei of cells as a template. The transcription process is performed by an enzyme which is known as RNA polymerase and several accessory proteins called transcription factors.

Complete answer:
The main goal of transcription is to generate a new copy of RNA from the sequence of DNA and the RNA transcript carries the information which is used in the encoding of a protein.
tRNA or transfer RNA is a small chain RNA that involves the transferring of a specific amino acid to a growing polypeptide chain and this transfer occurs during the translation. There is a site for attachment of amino acids present in a tRNA and there is also a three-base region which is called the anticodon. This anticodon recognizes the corresponding three-base codon region on mRNA via complementary base pairing.
In the case of eukaryotic cells, the transcription of tRNA is performed by RNA polymerase or RNA polymerase III. At first RNA polymerase III passes along the DNA to match the DNA nucleotides with a complementary RNA nucleotide. After the matching, it produced a new RNA molecule. This process of copying of the DNA going on until the RNA polymerase III arrived at a termination signal. The initial transcripts that are generated from tRNA genes are precursor molecules. They are then processed into mature tRNAs.
The primary transcript in eukaryotic cells is much more complex than the mature mRNA. This is known as the Heterogeneous nuclear RNA or in short hnRNA. hnRNA passes through the processing and eventually produces the mRNA. The hnRNA synthesis is performed by RNA polymerase II enzyme. This enzyme can read the DNA sequence and adds the complementary nucleotides for the production of new RNA molecules.
So, the RNA polymerase III and RNA polymerase II enzymes are responsible for the transcription of tRNA and hnRNA from template DNA strands.

Note: When the information present in a DNA strand is copied into a new molecule of messenger RNA or mRNA, is known as the transcription. The enzymes which are responsible for the transcription is known as RNA polymerase. There are various types of RNA polymerase found. In eukaryotic cells, RNA polymerase III enzymes have done the transcription of tRNA and the RNA polymerase II is involved in the transcription of hnRNA.