RNA is missing thymine (T) as one of its nitrogenous bases.
RNA vs. DNA: Key Differences
RNA (ribonucleic acid) and DNA (deoxyribonucleic acid) are both crucial nucleic acids involved in gene expression, but they have key differences in their structure and function. One significant difference lies in their nitrogenous base composition.
| Feature | RNA | DNA |
|---|---|---|
| Sugar | Ribose | Deoxyribose |
| Base Composition | Adenine, Guanine, Cytosine, Uracil | Adenine, Guanine, Cytosine, Thymine |
| Structure | Typically single-stranded | Typically double-stranded |
The Role of Uracil
Instead of thymine (T), RNA utilizes uracil (U). Uracil is a pyrimidine base that, like thymine, pairs with adenine (A). The absence of a methyl group on uracil makes it energetically less costly to produce compared to thymine, which is favorable for RNA's role in short-term gene expression. Thymine, on the other hand, is more chemically stable and resistant to mutation, a crucial characteristic for DNA's role in long-term genetic information storage.
In summary, RNA contains adenine, guanine, cytosine, and uracil, while DNA contains adenine, guanine, cytosine, and thymine. The substitution of uracil for thymine in RNA is a fundamental difference between these two vital nucleic acids.
