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Define nucleotides and give their functions.

Last updated date: 13th Jun 2024
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Hint: They are the building block of nucleic acid; DNA and RNA. Nucleotides are the first molecules arranged in the formation of sequence to make nucleic acid.

Complete Answer:
Nucleotides are the building blocks of macromolecules because they're the first molecules which are arranged during a sequence to make the nucleic acids.

- Nucleotides are the biomolecules comprising nitrogenous base sugar and a phosphate group in an appointment.
- The sugars which are present within the nucleotide are ribose or deoxyribose. The nitrogenous bases are purines and pyrimidines. The phosphate is present as orthophosphoric acid.
- The nucleotide is made by the union of a phosphate group with a nucleoside. A nucleoside, in fact, contains a sugar molecule alongside an organic nitrogenous base.
- Nucleotide is a structural and functional unit of nucleic acids. Each nucleotide has a sugar molecule (ribose or deoxyribose), phosphate moiety and nitrogenous base. There are two sorts of nitrogenous bases, namely purines (adenine and guanine) and pyrimidines (thymine, uracil and cytosine).
- The bottom of a nucleotide is joined covalently (at N-1 of pyrimidines and N-9 of purines) in an N –beta- glycosyl bond to the 1’ carbon of sugar. The phosphate is esterified to the 5’ carbon. This makes options A and D incorrect as a nucleotide can have either purine or pyrimidine.
- Apart from DNA and RNA are often bases in another molecule, like ATP (ATP).
- It’s also found in coenzymes like NAD, NADP and FAD in biochemical reactions that play a crucial role in metabolism and cell signaling.
- Another molecule that contains a nucleotide is cyclic AMP (cAMP), a messenger molecule.
- They supply energy for several cellular functions that require it. Examples are: proteins, aminooctanoic acid and cell wall synthesis, moving the cell and cell parts (both internally and intracellularly) and cellular division etc.

Note: The human genome is claimed to contain 3 billion nucleotide pairs, albeit human cells contain 6 billion nucleotide pairs.