Tuesday, April 24, 2012

WHAT IS RNA ???

WHAT IS RNA ???

Ribonucleic acerbic (RNA) is one of the three above macromolecules (along with DNA and proteins) that are capital for all accepted forms of life.

Like DNA, RNA is fabricated up of a continued alternation of apparatus alleged nucleotides. Each nucleotide consists of a nucleobase (sometimes alleged a nitrogenous base), a ribose sugar, and a phosphate group. The arrangement of nucleotides allows RNA to encode abiogenetic information. For example, some bacilli use RNA instead of DNA as their abiogenetic material, and all bacilli use agent RNA (mRNA) to backpack the abiogenetic advice that directs the amalgam of proteins.

Like proteins, some RNA molecules comedy an alive role in beef by catalyzing biological reactions, authoritative gene expression, or analysis and communicating responses to cellular signals. One of these alive processes is protein synthesis, a accepted action whereby mRNA molecules absolute the accumulation of proteins on ribosomes. This action uses alteration RNA (tRNA) molecules to bear amino acids to the ribosome, area ribosomal RNA (rRNA) links amino acids calm to anatomy proteins.

The actinic anatomy of RNA is actual agnate to that of DNA, with two differences--(a) RNA contains the amoroso ribose while DNA contains the hardly altered amoroso deoxyribose (a blazon of ribose that lacks one oxygen atom), and (b) RNA has the nucleobase uracil while DNA contains thymine (uracil and thymine accept agnate base-pairing properties).

Unlike DNA, best RNA molecules are single-stranded. Single-stranded RNA molecules accept actual circuitous three-dimensional structures, back they are not belted to the repetitive double-helical anatomy of double-stranded DNA. RNA is fabricated aural active beef by RNA polymerases, enzymes that act to archetype a DNA or RNA arrangement into a new RNA fiber through processes accepted as archetype or RNA replication, respectively.

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