cell organ - a specialized part of a cell; analogous to an organ; "the first organelle to be identified was the nucleus"cell - (biology) the basic structural and functional unit of all organisms; cells may exist as independent units of life (as in monads) or may form colonies or tissues as in higher plants and animals cilium - a hairlike projection from the surface of a cell; provides locomotion in free-swimming unicellular organisms organ - a fully differentiated structural and functional unit in an animal that is specialized for some particular function lysosome - an organelle found in the cytoplasm of most cells (especially in leukocytes and liver and kidney cells) nucleole, nucleolus - a small round body of protein in a cell nucleus; nucleoli contain RNA and are involved in protein synthesis centriole - one of two small cylindrical cell organelles composes of 9 triplet microtubules; form the asters during mitosis ribosome - an organelle in the cytoplasm of a living cell; ribosomes attach to mRNA and move down it one codon at a time and stop until tRNA brings the required amino acid; when a ribosome reaches a stop codon it falls apart and releases the completed protein molecule for use by the cell; "the ribosome is the site of protein synthesis" |