The Yeast Lab

Abstract

For our project, Adam and I, compared the growth of yeast based on the level of sugar placed in prior to growth.  The expected result was that the more sugar we put in the test tubes to make the yeast, the faster it would rise.  So we tested different sugar levels while growing yeast to see if this would hold true.

Introduction

While learning about cell respiration Adam and I were asked to come up with a variable that we could test to find out what directly affects cell respiration.  So using yeast that Mr. Quick provided we wanted to know if amount of sugar would affect what rate the yeast cells grew at.  We then tested 4 different sugar levels to find out their effects.

Hypotheses

We predicted that that the more sugar we put into the test tubes the more it would have to go through cell respiration and it would grow faster.

Materials

Our control was .1 g of sugar while our variables were .5, 1, and 1.5 grams of sugar. We put these in 4 different test tubes along with salt, water and the yeast cells.

Procedure and Conduct

Our procedure was simple, we mixed all of the materials together in order and put them in sealed test tubes connected to syringes.  We then would gently push on the syringes and then let them pop back up.  We did this over and over every five minutes to see how much gas was being produced in the test tubes.

Conclusion

The 1 and 1.5 grams of sugar were higher than the control respectively, but the .5 was above by quite a bit.  There is a couple things that this can be accredited to.  There could have been a problem with the syringes that measured the gas the yeast produced.  Another variable may have been made when the ingredients were being mixed; ie. too much sugar, etc.  So other than the outlier, this lab proved our hypotheses correct that more sugar means more respiration and more growth.