Agar

Definition

Agar is a gelatinous substance derived from red algae, primarily used as a solidifying agent in microbiological culture media. It provides a stable and nutrient-rich environment for the growth of microorganisms.

5 Must Know Facts For Your Next Test

1. Agar is extracted from red algae, specifically species like Gelidium and Gracilaria.
2. It remains solid at temperatures up to 100 degrees Celsius, making it ideal for incubating cultures.
3. Agar is not metabolized by most microorganisms, providing a stable medium for their growth.
4. It can be used to create both solid and semi-solid media depending on its concentration.
5. In addition to microbiology, agar is also utilized in food production as a thickening agent.

Review Questions

• From which type of algae is agar primarily derived?
• Why is agar considered an ideal solidifying agent for microbial cultures?
• What are two additional uses of agar outside of microbiology?

Related terms

Red Algae: A group of primarily marine algae from which agar is derived.

Culture Media: Substances that provide nutrients and environmental conditions for the growth of microorganisms.

Gelidium: A genus of red algae frequently used as a source for commercial agar production.