Growth medium

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An agar plate – an example of a bacterial growth medium. It is a 'streak plate': the orange lines and dots are bacterial colonies

A growth medium or culture medium is a solid or liquid containing nutrients. It is designed to support the growth of microorganisms or cells,[1] or small plants like moss.[2] There are different types of media for growing different types of cells.[3]

There are a wide range of growth media used in biology. Some of the basic types are:

  1. Undefined versus defined media: with defined media we know exactly what chemicals are in them.
  2. Selective media: for example, a medium with an antibiotic added. The only things which grow are those resistant to the antibiotic.
  3. Differential media: these distinguish one microorganism type from another growing on the same plate.
  4. Transport media: these have just enough to let organisms survive.
  5. Enriched media: contain extra amino acids and other building blocks. Used to harvest a wide range of organisms from a particular source.

References[change | change source]

  1. Madigan M. & Martinko J. (eds) 2005. Brock Biology of Microorganisms (11th ed.). Prentice Hall. ISBN 0-13-144329-1. 
  2. Hadeler, Birgit; Scholz, Sirkka & Reski, Ralf 1995. Gelrite and agar differently influence cytokinin-sensitivity of a moss. Journal of Plant Physiology 146, 369–371.
  3. Ryan K.J. & Ray C.G. (eds) 2004. Sherris Medical Microbiology. 4th ed, McGraw Hill. ISBN 0-8385-8529-9.