Question

Which of the following enzymes is responsible for reverse transcription?
A. RNA polymerase
B. Reverse transcriptase
C. DNA polymerase
D. Transcriptase

Answer 1

Hint: Reverse transcription is the process of generating complementary DNA (cDNA)from an RNA template with the help of an enzyme. Viruses like HIV and hepatitis B use reverse transcription to replicate their genomes. In molecular biology, this process is commonly used in PCR technique to RNA. The classical PCR technique is only applicable to DNA strands, but with the help of a special enzyme, RNA can be transcribed into DNA and analysed.

Complete explanation:
Option A: RNA polymerase is an enzyme that is used to synthesize RNA from a DNA template. It is used in several molecular techniques. The four types of RNA polymerase are RNA polymerase I, RNA polymerase II, RNA polymerase III and RNA polymerase IV.
Option A is incorrect.
Option B: Reverse transcriptase is an enzyme that is used to generate complementary DNA from an RNA template. This process is known as reverse transcription.
Option B is correct.
Option C:During cell division, the DNA polymerase functions by duplicating the DNA content of a cell. They add nucleotides at the three prime hydroxyl groups of the growing DNA strand.
Option C is incorrect.
Option D: Transcriptase is an enzyme that catalyses the generation of RNA from a DNA template during transcription. Transcriptase is the other name of RNA polymerase.
Option D is incorrect.

Hence the Correct answer is option B. Reverse transcriptase.

Note:
A popular technique used to identify rare mRNAs is reverse transcription polymerase chain reaction also known as RT-PCR. The procedure contains a two step reaction to amplify a fragment of the desired gene. In the first step, cDNA is generated from the RNA template using reverse transcriptase and oligo-dT as primer. In the second step of the procedure, cDNA of the desired gene is amplified with gene specific primers by PCR. RT-PCR is widely used in medical field for detection of diseases.