Home/Biology/Difference Between DNA and RNA

Difference Between DNA and RNA — NEET Biology

The main difference between DNA and RNA is that DNA is a double-stranded molecule with deoxyribose sugar that stores genetic information, while RNA is single-stranded with ribose sugar and functions in protein synthesis. This comparison is tested in NEET almost every year, with questions ranging from structural differences (sugar, bases) to functional roles (replication vs transcription).

Comparison Table: DNA vs RNA

BasisDNARNA
Full formDeoxyribonucleic acidRibonucleic acid
SugarDeoxyribose (lacks –OH at 2' carbon)Ribose (has –OH at 2' carbon)
Nitrogenous basesA, G, C, T (thymine)A, G, C, U (uracil replaces thymine)
StructureDouble-stranded helix (usually)Single-stranded (usually)
LocationNucleus, mitochondria, chloroplastNucleus, cytoplasm, ribosomes
FunctionStores and transmits genetic informationProtein synthesis (mRNA, tRNA, rRNA)
ReplicationSelf-replicatingSynthesized from DNA template
StabilityMore stable (double-stranded, deoxyribose)Less stable (single-stranded, reactive 2'–OH)
TypesOne type (but varies in form: A, B, Z)Three main types: mRNA, tRNA, rRNA
Base pairingA–T (2 H-bonds), G–C (3 H-bonds)A–U (in dsRNA regions like tRNA cloverleaf)

Key Points to Remember

  • DNA has deoxyribose sugar; RNA has ribose — the 2'–OH difference makes RNA less stable (NCERT Ch. 6)
  • Thymine in DNA is replaced by uracil in RNA — both pair with adenine
  • RNA is the genetic material in some viruses (e.g., TMV, HIV) — an NCERT-highlighted exception
  • Chargaff's rule (A=T, G=C) applies only to double-stranded DNA, not RNA
  • tRNA has the smallest size; rRNA is the most abundant RNA in the cell

NEET Exam Tip

How NTA Tests ThisNTA loves testing exceptions: 'Which virus has RNA as genetic material?' (TMV, HIV, Influenza). Also expect multi-statement questions mixing DNA/RNA features — e.g., 'Which of the following is true? (I) DNA has uracil (II) RNA is always single-stranded (III) rRNA is most abundant RNA' — statement III is correct, I and II are wrong.

Master NEET Biology with MedicNEET

12,771+ questions covering all Biology chapters — including comparison-based questions that match NTA's exact framing patterns.