RNA

ribonucleic acid that synthesizes protein within a cell, transferring information from DNA to the protein-forming system of the cell; also involved in expression and repression of hereditary information; its four main types are heterogeneous nuclear RNA (hRNA), messenger RNA (mRNA), transfer RNA (tRNA) and ribosomal RNA (rRNA).

defined: A chemical similar to a single strand of DNA. In RNA, the letter U, which stands for uracil, is substituted for T in the genetic code. RNA delivers DNA's genetic message to the cytoplasm of a cell where proteins are made. explained: Listen to a detailed explanation. Dr. Leslie Biesecker , of the National Human Genome Research Institute's Laboratory of Genetic Disease Research, defines RNA. illustrated:&nbspView illustration related terms:&nbspcell , deoxyribonucleic acid (DNA) , genetic code (ATGC) , messenger RNA (mRNA) , protein

(ribonucleic acid): A single-stranded nucleic acid that is found both in nucleus and cytoplasm. Other differences from DNA are: it contains uracil instead of thymine, it is single-stranded, and its sugar molecule is ribose. Total cellular RNA is made up of ribosomal RNA (rRNA, 80-85%), transfer RNA (tRNA, 15-20%) and messenger RNA (mRNA, 1-5%). See also small nuclear RNA and heterogeneous nuclear RNA.

Compare with nucleic acid and nucleotide .A nucleic acid with D-ribose as the sugar component in its nucleotides .