Question

fermentation – student worksheet
introduction to fermentation
fermentation is how cells make energy when there is no oxygen. it allows glycolysis to keep going by recycling a molecule called nad+. there are two types of fermentation:

• alcoholic fermentation: done by yeast. it makes alcohol and carbon dioxide. this is how bread rises and how alcoholic drinks are made.
• lactic acid fermentation: done by bacteria and your muscles. it makes lactic acid. this helps make yogurt and cheese and also causes sore muscles after exercise.

fermentation types chart

type of fermentation	who uses it?	what are the products?
lactic acid fermentation	bacteria, human muscles	lactic acid, nad+

questions

1. what allows glycolysis to continue during fermentation?

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1. what are two examples of food made by fermentation?

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1. why do your muscles sometimes feel sore after you exercise?

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Explanation:

For question 1: From the introduction, it says fermentation allows glycolysis to keep going by recycling NAD+. So the answer is the recycling of NAD+.
For question 2: The text mentions bread (from alcoholic fermentation by yeast) and yogurt (from lactic acid fermentation by bacteria), also cheese is mentioned. So two examples can be bread and yogurt (or cheese).
For question 3: The text states lactic acid fermentation in muscles makes lactic acid, which causes sore muscles after exercise. So the answer is because lactic acid fermentation occurs in muscles, producing lactic acid that causes soreness.

Answer:

1. The recycling of the molecule NAD+ allows glycolysis to continue during fermentation.
2. Two examples of food made by fermentation are bread and yogurt (or bread and cheese, yogurt and cheese).
3. Muscles feel sore after exercise because lactic acid fermentation occurs in them, producing lactic acid.