What are nucleoside bases?

What are nucleoside bases?

Nucleosides (bottom) are made of a nitrogenous base, usually either a purine or pyrimidine, and a five-carbon carbohydrate ribose. A nucleotide is simply a nucleoside with an additional phosphate group or groups (blue); polynucleotides containing the carbohydrate ribose are known as ribonucleotide or RNA.

What are the 3 parts of nucleotides?

Nucleotides contain three characteristic components: a nitrogenous base, a pentose, and one or more phosphate groups. The nitrogenous bases are derivatives of two parent heterocyclic compounds, purine and pyrimidine. The major pyrimidine bases are cytosine, thymine, and uracil.

Why are nucleotides called bases?

The nitrogenous bases of nucleotides are organic (carbon-based) molecules made up of nitrogen-containing ring structures. Why is it called a base? Each nucleotide in DNA contains one of four possible nitrogenous bases: adenine (A), guanine (G) cytosine (C), and thymine (T).

What are RNA bases?

An RNA molecule has a backbone made of alternating phosphate groups and the sugar ribose, rather than the deoxyribose found in DNA. Attached to each sugar is one of four bases: adenine (A), uracil (U), cytosine (C) or guanine (G).

What is meant by nucleoside?

nucleoside, a structural subunit of nucleic acids, the heredity-controlling components of all living cells, consisting of a molecule of sugar linked to a nitrogen-containing organic ring compound.

What are the 5 nucleosides?

The five bases that are found in nucleotides are often represented by their initial letter: adenine, A; guanine, G; cytosine, C; thymine, T; and uracil, U. Note that A, G, C and T occur in DNA; A, G, C and U occur in RNA.

What are the 4 nucleotides in RNA?

RNA consists of four nitrogenous bases: adenine, cytosine, uracil, and guanine.

Which bases are purines?

Purine bases include adenine (6-aminopurine) and guanine (2-amino-6-oxypurine) (Fig. 6.3).

What is a purine base?

Definition. A purine is an aromatic heterocyclic nitrogen compound, composed of a pyrimidine ring system fused to an imidazole ring system, with the core molecular formula C5H4N4. Purines are weakly basic compounds.

What are purine and pyrimidine bases?

Purines (adenine and guanine) are two-carbon nitrogen ring bases while pyrimidines (cytosine and thymine) are one-carbon nitrogen ring bases. Also Read: Amino Acids. Given below in a tabular column are the differences between Purines and Pyrimidines.

Which nucleotides are purines?

The purine nucleotide bases are guanine (G) and adenine (A) which distinguish their corresponding deoxyribonucleotides (deoxyadenosine and deoxyguanosine) and ribonucleotides (adenosine, guanosine). These nucleotides are DNA and RNA building blocks, respectively.