What is a nucleotide made up of?

A nucleotide is the basic building block of nucleic acids, such as DNA and RNA, and consists of three fundamental components: a phosphate group, a sugar molecule, and a nitrogenous base.

The phosphate group plays a crucial role in linking the nucleotides together, forming the backbone of DNA and RNA strands. The sugar component, which can be either ribose in RNA or deoxyribose in DNA, also contributes to the structure of the backbone. Lastly, the nitrogenous base varies among different nucleotides (adenine, thymine, cytosine, guanine in DNA; adenine, uracil, cytosine, guanine in RNA) and is responsible for encoding genetic information through sequence variations.

This combination of a phosphate group, a sugar, and a nitrogenous base allows nucleotides to function effectively in the storage and transmission of genetic information, making this option the correct description of a nucleotide's makeup.