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RNA
RNA Ribonucleic acid. A long-chain, usually single-stranded. The primary function of RNA is protein synthesis within a cell. However, RNA is involved in various ways in the processes of expression and repression of hereditary information. The three main functionally distinct varieties of RNA molecules are: (1) messenger RNA (mRNA) which is involved in the transmission of DNA information, (2) ribosomal RNa (rRNA) which makes up the physical machinery of the synthetic process, and (3) transfer RNA (tRNA) which also constitutes another functional part of the machinery of protein synthesis.
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Protein
Any of a group of complex organic compounds which contain carbon, hydrogen, oxygen, nitrogen, and usually sulfur, the characteristic element being nitrogen. Proteins, the principal constituents of the protoplasm of all cells, are of high molecular weight and consist essentially of combinations of a-amino acids in peptide linkages. Twenty different amino acids are commonly found in proteins, and each protein has a unique genetically defined amino acid sequence which determines its specific shape and function. Their roles include enzymatic catalysis, transport and storage, coordinated motion, nerve impulse generation and many others.
Cell
Fundamental structural unit of all life. The cell consists primarily of an outer plasma membrane, which separates it from the environment; the genetic material (DNA), which encodes heritable information for the maintainance of life; and the cytoplasm, a heterogeneous assemblage of ions, molecules, and fluid.
Repression
A defense mechanism, operating unconsciously, that banishes unacceptable ideas, fantasies, affects, or impulses from consciousness or that keeps out of consciousness what has never been conscious. Although not subject to voluntary recall, the repressed material may emerge in disguised form. Often confused with the conscious mechanism of suppression. resistance One's conscious or unconscious psychological defense against bringing repressed (unconscious) thoughts into conscious awareness.
Hereditary
Transmitted from parent to offspring; derived from ancestry.
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Rofecoxib
A substance used for pain relief that is also being studied for its ability to prevent cancer and to block the growth of new blood vessels to solid tumors. It belongs to the family of drugs called nonsteroidal anti-inflammatory drugs.
RNA
Ribonucleic acid
RNA. The generic term for polynucleotides, similar to DNA but containing ribose in place of deoxyribose and uracil in place of thymine. These molecules are involved in the transfer of information from DNA, programming protein synthesis and maintaining ribosome structure. The 4 main types of RNA are heterogeneous nuclear RNA (hRNA), messenger RNA (mRNA), transfer RNA (tRNA) and ribosomal RNA (rRNA).
Receptor
A molecule that recognizes a unique hormone. Once that hormone is bound to the receptor, the information carried by the hormone can now exert its biological action.
Retina
A membrane lining the inside of the back of the eye that contains light-sensitive nerve cells that convert focused light into nerve impulses, making vision possible.
Recessive gene
A gene that is inferior to another gene that controls the same trait (the dominant gene). The inferior gene does not get expressed in the presence of a dominant gene.
Rectum
An 8-inch chamber connected to the large intestine that receives solid waste (feces) from the descending colon to be expelled from the body. The rectum connects the colon to the anus. It is the rectum's job to receive stool from the colon, to let the person know that there is stool to be evacuated, and to hold the stool until evacuation happens.
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