Question

The enzyme required for transcription is
A. Restriction enzyme
B. DNA polymerase
C. RNA polymerase
D. RNAse

Answer 1

Hint: The genetic material or the DNA is responsible for bringing any types of changes or alteration in living organisms. In this sense, DNA acts as a blueprint based on which the different functions of the body are carried out. For carrying out successful operations of several biological functions, the body needs to produce different types of biomolecules such as proteins.

Complete answer:
The production of proteins is based on the nature of various coded information obtained from the DNA. The codes are obtained from the DNA and they are copied by the RNA and again processed to produce protein by the cell. The process of transcription occurs in both prokaryotic and eukaryotic cells. Prokaryotes are mostly single celled and lack well defined membrane bound organelles. A prokaryotic chromosome is a closed circle shaped structure with no well-defined histone proteins while in the eukaryotes the chromosomes are coiled and histone proteins are present.

Transcription is the primary step in a series of steps of gene expression of DNA. In this process, a segment of DNA is copied into RNA by using the enzyme RNA polymerase. It is a process in which information present in a particular stretch of DNA is copied and carried by a molecule of RNA. The molecule of RNA that carries the copied information is called the messenger RNA or mRNA. The mRNA carries the encoded information, but it is not an identical copy of the DNA molecule.

> The process of transcription begins due to the enzyme RNA polymerase and this enzyme binds to the template strand of DNA and it begins to catalyse production of complementary RNA. The process of transcription requires the partial unwinding of the DNA helix specifically at the region of mRNA synthesis. Transcription always proceeds from the template strand, which is the same strand for each gene. The mRNA is complementary to the template strand, but the only difference is the presence of uracil base in place of the thymine base.

Once a gene is transcribed, the polymerase is needed to be dissociated from the DNA template and the newly formed mRNA is released.

Hence, the correct answer is option (C).

Note: The synthesis of mRNA is initiated at the promoter sequence on the template strand of the DNA. During the process of transcription, the template DNA strand is copied into the mRNA strand and the process is initiated when the enzyme RNA polymerase or RNA pol binds to the template DNA.