Culture, Medium, and Host in Biology

Read biology's technical senses of words that mean something else in daily life.

Biology texts reuse familiar words in unfamiliar ways. A 'culture' in a lab is a population of microorganisms or cells grown under controlled conditions, not a society's art and customs. The 'medium' is the substance, often a gel or broth, in which that culture grows. A 'host' is an organism that another organism, such as a parasite or virus, lives on or in. Worked example: 'The technician transferred the culture to a fresh medium and observed that the bacteria had infected their host cells.

' Read with everyday meanings, this sentence is nonsense: artists, psychics, and party hosts. Read with biology's meanings, it is precise: a population of bacteria was moved to new growth material, and the bacteria had invaded the cells they live in. The skill is noticing the field you are reading in and switching your mental dictionary to match.

• 1A lab culture is a population of grown microorganisms or cells.
• 2A medium is the substance a culture grows in.
• 3A host is an organism another organism lives on or in.