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Yeast Fermentation

Question:

How will changing the amounts of sugar or flour (pick one) affect yeast metabolism?

Background:

What kind of organisms are yeast? What is the condition of the yeast when purchased from the store? What does the water do to the yeast? What might be the use of sugar and flour to yeast? What do you know about fermentation?

Hypothesis:

If the amount of ____ is increased, then the yeast metabolism will ___ (as evidenced by more/less CO2), because _____.

Materials


Procedure:

The students will describe in the procedure a way to estimate the CO2 produced. At the very beginning of the period, the students will label the bags, mix the ingredients, seal the bags and let them sit for 30 minutes in a beaker of warm water. Observe each bag after intervals of 15, 20, 25, and 30 minutes. Each time describe the appearance of each bag in your data table. The trick here is how to quantify the data!

Data:

Conclusion:

The hypothesis was "If the amount of _________ is increased, then the yeast metabolism will _______ (as evidenced by more/less CO2), because ______________."     The hypothesis was (rejected/supported).     The results of the test showed that ____ .     This (decrease/increase) in CO2 generated (agreed/disagreed) with the predicted results.