Living organisms are able to convert energy from food into chemical energy used by cells. This allows these organisms to perform all work needed to grow, reproduce and survive. To do so, both plants and animals depend on cellular respiration that uses oxygen to breakdown sugar. In the absence of oxygen, some organisms are still able to breakdown sugar in order to make ATP through lactic acid fermentation, like muscle cells or bacterial cells, or alcohol fermentation, like yeast. Yeast is one organism that is able to do both cellular respiration and fermentation depending on the presence or absence of oxygen.
- Read this about a boy named Stanley trying to learn more about wine making from his uncle George.
- Use what you have learned about cellular respiration and fermentation in chap 4 (sections 4.8 and 4.9) to explain to Stanley why the following conditions are needed to make wine:
- The air supply should be cut off from the container with grape juice and yeast mixture.
- The container should be sanitized to eliminate any bacteria that will cause the wine to have a sour taste.
What do you think the fermentation by bacterial cells can be used for? (think of some sour products that we eat regularly or use in our food)