Correct Answer: (D) complementary DNA

DNA synthesized from an RNA template through reverse transcription is known as complementary DNA (cDNA). This process reverses the normal transcription flow, using enzymes like reverse transcriptase to create a DNA copy of mRNA.​

Option Analysis

Recombinant DNA (A) refers to DNA formed by combining genetic material from different sources, such as in cloning or genetic engineering. It does not specifically involve RNA as a template.​

Transcript (B) denotes RNA produced from a DNA template during transcription, the opposite of the process described.​

T-DNA (C) stands for transfer DNA from Agrobacterium tumefaciens, used in plant genetic transformation. It originates from bacterial DNA, not RNA templates.​

Complementary DNA (D) matches exactly, as it is single- or double-stranded DNA synthesized from mRNA via reverse transcriptase, common in retroviruses and lab techniques like cDNA libraries.​

Complementary DNA, or cDNA, represents DNA synthesized from an RNA template, a key concept in molecular biology for competitive exams. This process, driven by reverse transcriptase, creates intron-free DNA copies ideal for gene cloning and expression studies.​

Reverse Transcription Process

Reverse transcriptase enzyme binds to mRNA, using it as a template to synthesize first-strand cDNA, followed by a second strand. Retroviruses like HIV rely on this for replication, integrating cDNA into host genomes.​

Applications in Research

cDNA libraries enable eukaryotic gene study in bacteria, aiding protein production and gene expression analysis. It supports PCR, microarrays, and therapies targeting viral infections.​

Exam Relevance

For IIT JAM Biotechnology or life sciences, distinguishing cDNA from recombinant DNA or transcripts tests understanding of central dogma exceptions. Practice questions emphasize this reverse flow.​