The correct option is
B Complementary DNA
The correct answer is option B.
Explanation of correct answer :-
- cDNA is an abbreviation for complementary DNA.
- cDNA is a DNA copy synthesized from mRNA by the action of reverse transcriptase.
- cDNA only has coding sequences.
- During transcription, both introns and exons are coded into messenger RNA (mRNA).
- 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.
- It is useful in bioinformatics and is also often used in gene cloning.
Explanation of incorrect answers :-
Option A
- Circular DNA is a form of closed-loop DNA that has no ends like a circle.
- This type of DNA is found in most prokaryotic cells.
- Also, it is seen in organelles like chloroplasts and mitochondria.
- The plasmid DNA is a classic example of extra-chromosomal circular DNA.
Option C
- Cytoplasmic DNA is a small circular chromosome present outside the nucleus.
- It is present within the cell organelles in the cytoplasm.
Final answer :cDNA stands for complementary DNA.