Yeast
Yeast are microorganisms. They are single-celled fungi. There are about 1,500 different species of yeast. Most reproduce asexually, by budding. Some use binary fission to reproduce asexually.
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| Yeast cells under a microscope. | |
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| A diagram of a typical yeast cell | |
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Ascomycota (sac fungi)
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A particular species of yeast, Saccharomyces cerevisiae, has been used for thousands of years. It is used for baking bread because the yeast makes carbon dioxide as a by-product of it eating sugar, which helps the bread rise (leaven). Yeast is also used for making beer and other alcoholic drinks by a process known as fermentation. This process produces both ethyl alcohol and carbon dioxide. Ethanol is also used as fuel, and to make other organic chemicals.
Yeast can be used to make electricity. Yeast is also a model organism for studying cell biology. Some yeasts can cause infections in humans (they are pathogens).
A block of fresh yeast
Dry yeast (usually, yeast is sold like this)
Yeast Media
The yeast cell's life cycle:- Budding
- Conjugation
- Spore
Yeast ring used by Swedish farmhouse brewers in the 19th century to preserve yeast between brewing sessions.
Bubbles of carbon dioxide forming during beer-brewing
Yeast in a bottle during sparkling wine production at Schramsberg Vineyards, Napa
Nutritional yeast flakes are yellow in colour
Diagram showing a yeast cell
Related pages
References
Other websites
Media related to Yeast at Wikimedia Commons