ribosomes defined in 1951 yearribosomes - ribosomes;
ribosomes - Granules of protein and RNA present in the cytoplasm of all types of organism, about 100 Angstrom in diameter and hence invisible with a light microscope. In eucaryotic cells they are often attached to endoplasmic reticulum. Their RNA is synthesized in nucleoli. They are the site of protein synthesis; messenger RNA attaches to them, and there receives molecules of transfer RNA bearing amino acids. Ribosomes are often linked together in a chain probably by a long molecule of messenger RNA; such groups are called polyribosomes, polysomes or ergosomes. Number of ribosomes in a polysome is probably related to length of messenger RNA molecule, and this in turn to the length of polypeptide chain to be formed.
near ribosomes in Knolik
definition of word "ribosomes" was readed 1361 times