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Respiration

What is the equation when yeast reacts with glucose? Is it the one that produces ethanol and carbon dioxide or water and carbon dioxide?

Reply 1

MadNatSci

Yeast doesn't, strictly speaking, react with glucose but it does respire using it :smile:

In aerobic conditions (ie they can respire using oxygen and glucose) you'll get the same products as we make when we respire: water and carbon dioxide (as well as some energy in the form of ATP!)

In anaerobic conditions the yeast produce ethanol and carbon dioxide. This is why if you want to make beer you have to make sure no oxygen gets into the fermentation chamber, otherwise you don't get ethanol - yeast is a facultative anaerobe (ie it can respire anaerobically if it needs to) but it prefers to use oxygen!

So the short answer to your question is 'both' :wink: