# The Effect of Food Availability on the Cellular Respiration of Yeast

## Abstract

In this experiment, I observed which conditions were optimal for cellular respiration of

yeast (*Saccharomyces cerevisiae*). Because CO_{2} is released during respiration of yeast, this

provides a way of measuring how much cellular respiration has taken place (Rymer, 2019). As

CO_{2} is produced, the gas can be trapped and measured. I manipulated the amount of food (in this

case, the amount of sucrose) to see how this affected the rate of cellular respiration by yeast. I

measured the volume of CO_{2} collected at 4 different treatment levels: 0g of sucrose (control), 5 g

of sucrose, 15 g of sucrose, and 30 g of sucrose. Since yeast must get their food from their

surrounding environment in order to grow and reproduce, I hypothesized that if we use 15 g of

sucrose, then this treatment level with the yeast will produce the most CO_{2} and will therefore

have the fastest rate of cellular respiration (mL CO_{2}/minute). If we were to add 0 g of sucrose or

30 g of sucrose (i.e. too little or too much sucrose), then these environments will show to be the

least optimal conditions for yeast activity and produce the least CO_{2} with the slowest rate of

cellular respiration (mL CO_{2}/minute). After completing the data collection phase of my

experiment, the cellular respirations rates were calculated for each treatment. A one-way ANOVA

test was used to evaluate the statistical difference between these results. It was found that the

results were statistically significant with a reported p-value of 1.0629e-65 which is less than the

threshold of 0.05 (p < 0.05). Therefore, there was sufficient evidence to reject the null hypothesis

and we can conclude that of the three treatment levels, adding 5 g of sucrose (treatment group B)

was the most optimal conditions for cellular respiration of yeast. For future studies, we can

evaluate the effects of manipulating other environmental factors on the growth of yeast, such as

temperature, pH levels, and type of sugar (i.e. glucose, fructose, galactose).