University of Central Florida (UCF) BSC1005 Biological Principles Practice Exam 2

A nucleotide is the basic building block of nucleic acids, such as DNA and RNA, and is composed of three main components: a sugar, a phosphate group, and a nitrogenous base. The sugar can be either ribose (in RNA) or deoxyribose (in DNA), and it forms the backbone of the nucleotide. The phosphate group is attached to the sugar and contributes to the overall structure and function of nucleic acids, facilitating the formation of the phosphodiester bond that links nucleotides together. The nitrogenous base is attached to the sugar and is crucial for encoding genetic information; it can be one of five types: adenine, thymine, cytosine, guanine, or uracil.

An amino group, which consists of a nitrogen atom bonded to two hydrogen atoms, is not a component of nucleotides. Instead, amino groups are typically associated with amino acids, the building blocks of proteins. Thus, the identification of the amino group as not being part of a nucleotide reinforces the distinction between nucleotides and amino acids in biochemistry and molecular biology.