DNA stands for deoxyribonucleic acid, which is the hereditary material present in all prokaryotic cells, eukaryotic cells, and some viruses. All the genetic information are encoded in the DNA, which is inherited from parents to offsprings. DNA is mainly present in the chromatin of the cell nucleus and also in mitochondria.
RNA stands for ribonucleic acid, which is present in all living cells and in some viruses. It is mainly involved in the synthesis of protein. RNA is present mainly in the cell cytoplasm and a few in the nucleolus.
DNA and RNA are polymers made up of nucleotides. It consists of phosphodiester bonds, sugars, and nitrogenous bases. Deoxyribose sugar is present in DNA, and ribose sugar is in RNA. The name deoxy suggests an absence of oxygen, which occurs in carbon number 2 of deoxyribose sugar. In the ribose sugar, the OH group is present. The nitrogenous bases present in both DNA and RNA are adenine (A), guanine (G), and cytosine (C). Thymine (T) is present in DNA which is replaced by uracil (U) in RNA.
| Characteristics | DNA (Deoxyribonucleic acid) | RNA (Ribonucleic acid) |
| Number of strands | DNA is usually double-stranded except in parvovirus (single-stranded DNA). | RNA is usually single-stranded except in reovirus (double-stranded RNA). |
| Nitrogenous bases | The nitrogenous bases present in DNA are adenine (A), guanine (G), cytosine (C ), and thymine (T). | The nitrogenous bases present in RNA are adenine (A), guanine (G), cytosine (C ), and Uracil (U). |
| Pairing of nitrogenous bases | G pairs with C in triple bonds, and A pairs with T in double bonds. | The GC boding is similar to DNA, but A pairs with U in double bonds. |
| Sugar | Deoxyribose sugar is present in DNA. The carbon number 2 of deoxyribose sugar contains a hydrogen (H) atom. | Ribose sugar is present in RNA. The carbon number 2 of ribose sugar contains hydroxyl (OH) group instead of hydrogen (H) atoms. |
| Types | There are two types of DNA based on location, i.e., nuclear DNA and mitochondria DNA. There are different types of DNA based on forms, i.e., A-DNA, B-DNA, C-DNA, D-DNA, E-DNA, and Z-DNA | There are three major types of RNA based on their function, i.e.,mRNA (messenger RNA), tRNA (transfer RNA), and rRNA (ribosomal RNA). Based on coding, RNA are two types, i.e., coding (cRNA) and noncoding RNA (ncRNA). |
| Stability | DNA is less reactive than RNA due to the presence of C-H bonds. It is stable in alkaline conditions. DNA grooves are smaller, so destructive enzymes can’t bind easily in them and attack the DNA. | RNA is more reactive than DNA due to the presence of hydroxyl bonds. It is not stable in alkaline conditions. RNA grooves are larger, so destructive enzymes can bind easily in them and attack the RNA. |
| Proportion of purine and pyrimidine | DNA has an equal proportion of purine and pyrimidine. | Purine and pyrimidine are not in equal proportion. |
| Synthesis | New DNA strands are synthesized by replication. | RNA is synthesized by transcription. |
| Primer | Primer is required during DNA synthesis. | Primer is not required during RNA synthesis. |
| Degrading enzyme | The enzyme that degrades the DNA is called deoxyribonuclease. | The enzyme that degrades the RNA is called ribonuclease. |
| Leaving nucleus | DNA can not leave the nucleus. | RNA can leave the nucleus. |
| Nucleotides and molecular weight | DNA has many nucleotides (up to 3-4 million) and high molecular weight. | RNA has a few nucleotides (up to 12000) and has a low molecular weight. |
| UV damage | DNA is more susceptible to UV damage as compared to RNA | Resistant to UV damage as compared with DNA |
References
- Madigan, M. T., Martinko, J. M., Stahl, D. A., & Clark, D. P. (2011). BROCK Biology of Microorganisms (13th edition). Benjamin Cumming.
- Pelczar Jr., M., Chan, E., & Krieg, N. (2007). Microbiology (5th edition). Tata McGraw-Hill.
