GLOSSARY: Tissue Culture
A Tissue Culture is defined as growing mammalian cells in the laboratory in a tissue culture medium (in vitro). For example, this allows researchers to determine the effects of various chemicals on mammalian cells without experimenting directly on live animals or man. Since a molecule of some toxic substances can harm a single mammalian cell, even one part-per-billion of some impurities can affect a tissue culture. Therefore, water used to make up tissue culture media should be extremely pure.