A Level Biology Practice Exam

What is the role of nucleotides in the formation of nucleic acids?

1. They serve as energy carriers

2. They act as signaling molecules

3. They are the monomers used to build nucleic acids

4. They promote cellular respiration

The correct answer is: They are the monomers used to build nucleic acids

Nucleotides serve as the fundamental building blocks, or monomers, for the formation of nucleic acids, such as DNA and RNA. Each nucleotide consists of three components: a nitrogenous base, a five-carbon sugar (ribose in RNA and deoxyribose in DNA), and a phosphate group. The structure of nucleotides allows them to link together through phosphodiester bonds, forming long chains that compose the backbone of nucleic acid molecules. The sequence of nitrogenous bases along these chains encodes genetic information, providing the instructions necessary for the synthesis of proteins and the regulation of various cellular processes. This role in constructing nucleic acids is central to the processes of heredity, gene expression, and the transmission of genetic information across generations.