Biology · Molecular Basis of Inheritance · NEET
It is the rule that tells you the direction genetic information moves inside a cell. Information goes from DNA to RNA to Protein. DNA holds the instructions, RNA carries a copy of the instructions, and protein is the final working product. This one-way flow is the normal path in almost all living cells.
Francis Crick proposed the central dogma in molecular biology. NCERT states it clearly: the genetic information flows from DNA to RNA to Protein. Note that Crick also co-discovered the DNA double helix with Watson, so his name appears in more than one NEET topic. Do not confuse the person who proposed the dogma (Crick) with the people who named reverse transcription.
There are three key processes. Replication copies DNA to DNA (the self-loop on DNA). Transcription copies DNA to RNA. Translation reads RNA to build protein. In a simple flow chart: DNA has an arrow back to itself (replication), an arrow to RNA (transcription), and RNA has an arrow to protein (translation).
Reverse transcription is when the flow goes backwards, from RNA to DNA. NCERT says: in some viruses the flow of information is in the reverse direction, that is, from RNA to DNA. These viruses are retroviruses, like HIV. The enzyme that does this is reverse transcriptase. This is the main exception to the central dogma that NEET tests.
No. Transduction is NOT a central dogma step. Transduction means transfer of DNA from one bacterium to another using a bacteriophage. NTA puts transduction inside the options to trick you. The three real steps are replication, transcription, and translation. If you see transduction in a central dogma flow-chart option, that option is wrong.
It is an exception, not a full break. The normal flow is DNA to RNA to Protein. Reverse transcription adds a special path RNA to DNA seen only in retroviruses. Information never flows from protein back to nucleic acid, so protein is always the end point. For NEET, remember: reverse transcription is RNA to DNA, and it happens in some viruses, not in all cells.
Complete the flow chart on central dogma. The flow chart shows DNA with a self-directed arrow (a) back to DNA, an arrow (b) from DNA to RNA, and an arrow (c) from RNA to (d).
Try the real previous-year questions from this chapter — each with the answer and a full solution.
DNA to RNA to Protein. DNA makes RNA by transcription, and RNA makes protein by translation.
Transcription copies DNA into RNA (nucleic acid to nucleic acid). Translation reads RNA to build a protein (nucleic acid to protein). Transcription comes first, translation comes second.
Reverse transcriptase. It builds DNA using an RNA template, so information flows from RNA to DNA. It is found in retroviruses like HIV.
No. In the central dogma, protein is always the final product. Information never flows from protein back to nucleic acid.
It is a high-yield, direct-recall topic. NEET asks about the flow direction, who proposed it (Crick), and reverse transcription in viruses. Knowing the exact arrows and terms wins easy marks.
