Nucleotides and nucleic acids have a wide range of functions, from simple building blocks in the human body, to cell signaling to energy generation.
As primary building block monomers, nucleotides have a wide range of uses in the human body. Aside from being used in nucleic acid chains to construct DNA, they are also used to form RNA. Ribonucleic acid (RNA) differs in structure and function to DNA and there are many versions of it. mRNA is messenger RNA which is used to make single-stranded copies of DNA and is read by ribosomes to produce proteins in the cell. tRNA, known as transport RNA is also important in the creation of proteins, as it carries the amino acids to match up to the mRNA being read by the ribosome. rRNA, known as Ribosomal RNA is an important component of ribosomes and used to build ribosome structures to read mRNA and create proteins from amino acids
Nucleotides are also found in Adenosine triphosphate (ATP) which is the energy store in the cell. Adenine, a nitrogenous base found in DNA and RNA, is the base structure that phosphate groups are attached to. These phosphate groups carry energy in their bonds that, when broken, can be used to drive cellular processes. GTP and GDP are a guanine based form of ATP and ADP and is often found in the production of RNA during transcription and signal transduction in cells.
Nicotinamide-adenine dinucleotide is an important cofactor in many metabolic reactions in the cell in both its oxidized (NAD+) and reduced (NADH) forms.
Free nucleotides can also be used as signals throughout the cell, promoting the cell to divide or to make proteins when they interact with certain enzymes.
Practice Questions
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Key Points
• Nucleic acids such as RNA are used in the translation and transcription of DNA to produce proteins in cells.
• Nucleotides like adenosine are used in energy generation through the structure of ATP and cell signaling in the cell. GTP and GDP are guanine based forms of ATP and are used in RNA synthesis.
• NADH and NAD+ are the reduced and oxidized forms, respectively, of the nicotinamide-adenine dinucleotide that is essential for cell metabolism.
Key Terms
Nucleotide: the monomer comprising DNA or RNA polymer molecules; consists of a nitrogenous heterocyclic base that can be a purine or pyrimidine, a five-carbon pentose sugar, and a phosphate group
Nucleic acid: polymers comprised of many nucleotides bonded together, found in the cells in two forms, RNA and DNA
DNA: Deoxyribonucleic acid, the genetic material found within the cell nucleus
RNA: Ribonucleic acid, codes for proteins at ribosomes
ATP: Adenoside triphosphate, cellular energy storage unit
Nicotinamide-adenine dinucleotide: NAD+ and NADH
Guanosine triphosphate (GTP) and guanosine diphosphate (GDP): A molecule that acts as a source of energy for signal transduction events.