The basic building blocks of DNA and RNA are called nucleotides. Both DNA (deoxyribonucleic acid) and RNA (ribonucleic acid) are composed of these nucleotides, which are the fundamental units that carry genetic information.
A nucleotide consists of three components:
- A nitrogenous base: This can be one of four types in DNA (adenine, thymine, cytosine, guanine) and one of four types in RNA (adenine, uracil, cytosine, guanine). The nitrogenous base is crucial as it determines the genetic code.
- A sugar molecule: In DNA, the sugar is deoxyribose, whereas in RNA, it is ribose. The difference between these sugars is the presence of one less oxygen atom in deoxyribose compared to ribose.
- A phosphate group: This is a molecule made up of phosphorus and oxygen. The phosphate group connects the sugar of one nucleotide to the sugar of another, forming a long strand of DNA or RNA.
In summary, nucleotides, made up of a nitrogenous base, a sugar, and a phosphate group, are the essential building blocks that make up the structures of DNA and RNA, enabling them to store and transfer genetic information in all living organisms.