SSC CGL 2025 Tier-I · 16 September 2025, Shift 3 · General Awareness · Question 16 of 75

We transcribed this text from the pictures on a candidate's response sheet for this shift; the answer is the key SSC colour-marked on that sheet. Solution last reviewed 13 September 2026.

Where this paper and its answers come from

SSC does not publish CGL question papers or a public answer key. From 2025 the candidate response sheet prints every question and option as a picture, so the text here is transcribed from those pictures for this shift and checked against them independently; where the layout carries meaning, the picture is shown as well. Each answer is the key SSC colour-marked on that sheet. SSC released a tentative key for challenge and later its final one, both only to candidates behind a login, and the sheet does not say which of the two it carries. The solutions are written by UnlockIAS.

Which of the following sequences correctly represents flow of genetic info?

(a)DNA → Protein → RNA
(b)RNA → DNA → Protein
(c)DNA → RNA → Protein
(d)Protein → RNA → DNA

Answer

Why

Correct — C. Genetic information flows DNA → RNA → Protein.

Transcription: RNA polymerase copies a gene's DNA into messenger RNA (mRNA).
Translation: a ribosome reads the mRNA three bases (one codon) at a time and joins amino acids into a protein.

Francis Crick's central dogma (1958) adds the rule behind the arrows: once information has passed into protein, it cannot get out again.

Why the others are wrong

(a)
DNA → Protein → RNA — Protein cannot serve as a template for RNA. Ribosomes build protein by reading mRNA, so RNA must come before protein, not after it.
(b)
RNA → DNA → Protein — RNA → DNA does occur, as reverse transcription in retroviruses such as HIV, but it is an exception. And DNA is never translated straight into protein: mRNA comes in between.
(d)
Protein → RNA → DNA — This runs the flow backwards. The central dogma rules out any transfer of sequence information from protein back to RNA or DNA.

Concept

The central dogma describes how sequence information moves between DNA, RNA and protein. DNA stores it. A gene is transcribed into mRNA in the nucleus, and the mRNA moves to a ribosome in the cytoplasm, where it is translated into a chain of amino acids.

Information also passes from DNA to DNA (replication) and, in retroviruses, from RNA to DNA. What never happens is a transfer out of protein.

Crick's own statement is about what cannot happen. The tidy chain DNA → RNA → Protein is the simplified version popularised by James Watson's 1965 textbook, and both lead to the same answer here.

Key facts

Transcription (DNA → mRNA) is carried out by the enzyme RNA polymerase.
Translation (mRNA → protein) takes place on ribosomes, which read codons of three bases.
Reverse transcription (RNA → DNA) occurs in retroviruses such as HIV, using reverse transcriptase.
Crick published the central dogma in 1958: information that has passed into protein cannot get out again.

Study next

Types of RNA and their jobs: mRNA, tRNA and rRNARetroviruses and reverse transcriptaseWhere protein synthesis happens: nucleus, cytoplasm and ribosomes

Common traps

Choosing RNA → DNA → Protein after remembering reverse transcription, a viral exception rather than the general flow.
Thinking DNA is translated directly into protein and forgetting the mRNA step.

The four options are rearrangements of the same three molecules, so the question tests the order of the flow rather than the names.

Related PYQs

No directly related past PYQ was found.

Topic: Scientific Research — all 220 SSC CGL questions on it, every solved shift.