Question

cDNA is
a) Circular DNA
b) Coiled DNA
c) Cytoplasmic DNA
d) Complementary DNA

Answer 1

Hint: c-DNA is the DNA that is synthesized from the RNA. They are synthesized from the single-stranded RNA which are messenger RNA or micro RNA. This reaction is catalyzed by the enzyme reverse transcriptase. This type of DNA is used to clone the eukaryotic genes in the prokaryotes.

Complete answer: The c-DNA in genetics is also known as the complementary DNA. It is synthesized from the single-stranded RNA by the template reaction and this reaction is catalyzed by the enzyme reverse transcriptase. Complementary DNA contains the coding regions only and has the absence of the non-coding region making them different from the DNA present in the genes. The DNA present in the genes contains both the introns and the exons. The c-DNA is used when in a certain cell a particular protein-coding is absent then they are transferred to such cells in order to make desired proteins. The main advantage of using c-DNA for this technique is that they don’t have the presence of both the introns and exons as in the genomic DNA making them easy to transport and then get transcribed. The c-DNA can be obtained as the single intron free segment. The c-DNA is produced when the desired protein needs to be transferred to an organism. They are made from that particular protein-coding mRNA. Hence, libraries of such proteins can be created and used.

So, the answer is ‘complementary DNA’.

Note: The synthesis of DNA from an RNA strand leads to the formation of the c-DNA. The presence of c-DNA can be done by the process of polymerase chain reaction and if we are able to amplify large segments without the contamination of the genomic DNA then once can say that they have obtained high quality c-DNA.