T cell

A type of white blood cell that plays an essential role in the immune system. The "T" stands for thymus which is the organ where the cells mature (as opposed to another type of white blood cell, called B cells, which mature in the bone marrow). Subsets of T cells express different receptors on the surface of the cell and perform specific functions. Also known as a T lymphocyte. 

Toxin

A poison that produces illness by affecting bodily functions

Transcription

The process by which the genetic information encoded in DNA is copied into a complementary copy in RNA