chromosome

n. a strand or filament composed of nucleic acid (mainly DNA in humans) and proteins (see chromatin) that carries the genetic, or hereditary, traits of an individual. Located in the cell nucleus, chromosomes are visible, through a microscope, only during cell division. The normal human complement of chromosomes totals 46, or 23 pairs (44 autosomes and 2 sex chromosomes), which are believed to contain a total of 20,000 to 25,000 genes (see genome). Each parent contributes one chromosome to each pair, so a child receives half its chromosomes from its mother and half from its father. —chromosomal adj.

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Psychology term of the day

March 16th 2025

imipramine

n. a tricyclic antidepressant (TCA) with a tertiary amine molecular structure. It was originally synthesized in the hope of creating an effective antipsychotic but was observed to be ineffective in reducing psychotic symptoms. It did, however, seem to help individuals with severe depression and was subsequently marketed as an antidepressant. It is considered the prototype TCA, and like all tricyclic agents, its use as an antidepressant has been largely supplanted by less toxic drugs. It retains a therapeutic role as a sedative and adjunct in the management of neuromuscular or musculoskeletal pain. U.S. trade name: Tofranil.