Yeast are single-celled organisms in the Fungi kingdom. One species of yeast called Saccharomyces cerevisiae (Figure 1) has been used in baking and alcoholic beverages for thousands of years. Scientists have also used it to gather information about how cells function because it reproduces quickly. In fact, S. cerevisiae and many other species of yeast can produce a new generation every two hours. In nature, an open population system may increase or decrease in size as organisms enter or leave and materials cycle through the population.
The yeast Population will be grown in a closed system (flask). Therefore, a population of yeast could potentially increase in size very quickly if something did not prevent the size of the population from growing over time. The guiding question of this investigation is, What factors limit the size of a population of yeast?
HYPOTHESIS: "IF a population of _______ is grown in a _______ system, THEN the ________ population will exhibit a: logistic OR exponential (choose 1) type of growth BECAUSE ....(describe any limiting factors if present)."
HOW MANY CELLS DO YOU COUNT? Experimental Flask & Control Flask
400X Both contain 100ml of YPD (yeast food) and were sterilized