Thursday, June 11, 2009

General Science: What's a yeast's favorite food?

This week we learned a little bit about our tiny unicellular fungal friend, the yeast. After all, we have a lot in common: We eat, reproduce, respire...we're practically identical. So when it came to investigating which foods yeast like best, we decided to use something else we have in common: When we're done eating (and transforming the energy from food into energy our cells can use), we all release carbon dioxide. This comes in handy when we use yeast to help us make bread. It is the carbon dioxide gas that causes the bread to rise.

We compared carbon dioxide production in yeast when fed 5 different kinds of food: salt, flour, sugar, ground-up cookies, and ground up vaflim (wafers). To get an idea of which food was eaten most heartily by our yeast, we covered each bottle with a balloon. Then we sat back and watched the show. The samples of yeast fed sugar, cookies, and vaflim were the happiest, i.e. the balloons were the most inflated because of the greater production of carbon dioxide. The flour came in second place. We discussed how cookies contain sugar, and how flour, a complex sugar, can be broken down into simpler sugars. A little more work, but when you're hungry, you do what you have to. Yet one more thing we and yeast have in common...LAZINESS! Who here isn't counting down the days 'till summer vacation?!

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