| Criteria | DNA (Deoxyribonucleic Acid) | RNA (Ribonucleic Acid) | Remarks |
| Structure | Double-stranded helix (typically B-form); antiparallel strands | Single-stranded (can form secondary structures like hairpins) | DNA’s stable double helix ensures long-term storage; RNA’s flexibility supports diverse functions. |
| Sugar Component | Deoxyribose (lacks 2′-OH group on the pentose sugar) | Ribose (has 2′-OH group on the pentose sugar) | The 2′-OH makes RNA more reactive and less stable than DNA. |
| Nitrogenous Bases | Adenine (A), Thymine (T), Guanine (G), Cytosine (C) | Adenine (A), Uracil (U), Guanine (G), Cytosine (C) | RNA uses uracil instead of thymine, affecting base pairing and recognition. |
| Base Pairing | A pairs with T, G pairs with C | A pairs with U, G pairs with C (in duplex regions) | Base pairing in RNA occurs in structured regions (e.g., stems in tRNA, rRNA). |
| Function | Long-term storage and transmission of genetic information | Short-term storage, transmission, and execution of genetic information | DNA is genetic blueprint; RNA is the functional intermediate and sometimes catalytic. |
| Location in Cell | Primarily in the nucleus (and mitochondria) | Synthesized in nucleus; functions in cytoplasm (and nucleus) | RNA must move between compartments to perform its roles. |
| Stability | Chemically and enzymatically stable under physiological conditions | Less stable due to 2′-OH group and susceptibility to RNases | DNA’s stability is ideal for long-term information storage; RNA’s instability suits transient expression. |
| Types | One main type (with nuclear and mitochondrial variants) | Multiple types: mRNA, tRNA, rRNA, snRNA, miRNA, siRNA, etc. | RNA diversity enables complex regulatory and catalytic roles. |
| Replication | Self-replicating with help of DNA polymerases | Synthesized from DNA template via transcription (RNA polymerase) | Only DNA is self-replicating; RNA is produced as needed. |
| Enzymes Involved | DNA polymerases, DNA ligase, helicases | RNA polymerase, splicing enzymes, ribonucleases | Different enzymatic machinery reflects distinct biosynthetic roles. |
| Genetic Role | Carries the full genome and is inherited across generations | Acts as messenger (mRNA), translator (tRNA), ribosomal component (rRNA), regulator (miRNA, siRNA) | RNA performs multiple gene expression-related functions. |
| Catalytic Ability | Lacks catalytic function | Some RNAs have enzymatic activity (ribozymes, e.g., in ribosome) | RNA’s catalytic role supports the “RNA world” hypothesis. |
| Strand Length | Long and continuous (genome-sized; chromosomes) | Shorter; varies with type and function (e.g., mRNA vs. miRNA) | RNA length reflects function—longer RNAs (e.g., mRNA), short regulatory RNAs (e.g., miRNA). |
| Reactivity | Low (chemically inert under normal conditions) | High (chemically reactive due to 2′-OH and less stable bonds) | RNA is more prone to hydrolysis and chemical degradation. |
| Transmission | Inherited from parents to offspring | Synthesized as needed; not inherited | DNA is genetic material; RNA is produced anew in each cell or condition. |
| Modification | Rare modifications (e.g., methylation of bases for epigenetic regulation) | Extensive post-transcriptional modification (e.g., capping, splicing, editing) | RNA undergoes complex processing to become functional. |
