Question

cDNA is synthesized by

• A. Circular DNA
• B. Recombinant DNA
• C. RNA template
• D. None of these

Answer 1

The correct option is C

RNA template

The correct option is C.

Explanations of correct option:

1. cDNA is a double-stranded DNA copy derived from messenger RNA via Reverse Transcriptase.
2. Complementary DNA only possesses a coding sequence since it is a result of intron-free mRNA.
3. During transcription, both introns and exons are coded into messenger RNA (mRNA).
4. But, the introns are removed from mRNA to produce a mature mRNA by splicing the exons together which produces cDNA, containing only the protein-coding regions of the genome.
5. It is useful in bioinformatics and is also often used in gene cloning.

Explanations of incorrect options:

Option A

1. Circular DNA is a form of closed-loop DNA that has no ends like a circle.
2. This type of DNA is found in most prokaryotic cells.
3. Also, it is seen in organelles like chloroplasts and mitochondria.
4. The plasmid DNA is a classic example of extra-chromosomal circular DNA.

Option B

1. Recombinant DNA is the method of joining two or more DNA molecules to create a hybrid.
2. The technology is made possible by two types of enzymes, restriction endonucleases, and ligases.
3. It involves the transfer of specific genes from one organism to another by using restriction endonuclease enzyme and appropriate vectors.

Final Answer: cDNA is synthesized from the mRNA Template.