Observing Cellular Respiration in Yeast
Objective: Observe cell respiration in yeast.
Background:
Respiration is the process by which cells take in oxygen and release carbon dioxide and energy. It is a
step-by-step breakdown of glucose molecules in which energy is released. Respiration happens in all
living cells, and it can occur both day and night.
The equation for cellular respiration is:
C6H12O6 + 6O2 6CO2 + 6H20 + energy
(Glucose + Oxygen yields Carbon Dioxide + Water + Energy)
You may notice that the equation for cellular respiration is the opposite of the equation for photosynthesis.
Most cells carry out the process of cellular respiration using oxygen (aerobic); however, some are
anaerobic. Anaerobic organisms do not use oxygen to break down glucose or have limited supplies in
which to carry out this task. The energy released from glucose is converted to ATP and is required for all
cellular functions for the survival of the cell/organism. The organelle, where aerobic respiration takes
place in the cell, is the mitochondrion. Anaerobic respiration (fermentation) takes place in the cytoplasm.
In this investigation you will work with yeast. Yeast is a one-celled fungus that reproduces rapidly under
the right conditions with an ample food supply.
Materials:
ll, 6”–7” size)
Diameter of Balloon at Two Minute Intervals
Time (minutes)
Diameter (in cm)
2
3
4
5
6
8
8
12
10
13
12
15
14
16
16
17
18
19
20
22
Data Analysis:
Make a line graph of your data. Remember to keep in mind the differences between the independent and
dependent variable when graphing, and don’t forget to provide a title and label your axes.
Analysis and Conclusion:
1. What was your evidence that cellular respiration was occurring?
2. What provided the energy (food) for the yeast to carry out cellular respiration?
3. What gas inflated the balloon?
4. What conclusion can you draw about how anaerobic respiration in yeast aids the making of bread?