Lab Manual - eScience Labs
Lab Manual - eScience Labs
Lab Manual - eScience Labs
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<strong>Lab</strong> 8: Respiraon<br />
6. Oponal: Using the leover yeast, test some other carbohydrates (e.g. brown sugar, molasses)<br />
from your cupboard to see if the rates of respiraon differ. Report your experimental procedure<br />
and results below.<br />
Experiment 2: Aerobic Respiraon in Beans<br />
We will evaluate respiraon in beans by comparing carbon dioxide producon between germinated<br />
and non-germinated beans. As shown in the balanced equaon for cellular respiraon, one of the byproducts<br />
is CO 2 (carbon dioxide):<br />
C 6 H 12 O 6 + 6H 2 O + 6O 2 energy + 6CO 2 +12H 2 O<br />
We will use a carbon dioxide indicator ( bromothymol blue) to show oxygen is being consumed and<br />
carbon dioxide is being released by the beans. Bromothymol blue is an indicator that turns yellow in<br />
acidic condions, green when it is neutral and blue when it is in basic condions. When carbon dioxide<br />
dissolves in water, carbonic acid is formed by the reacon:<br />
H 2 O + CO 2 H 2 CO 3<br />
resulng in the formaon of this weak acid. If an indicator such as bromothymol blue is present, what<br />
do you think would happen? (Hint—what color would the indicator change to?)<br />
Materials<br />
100 Pinto beans<br />
100 Kidney beans<br />
6 250mL beakers<br />
Paper towels*<br />
6 Measuring cups (small white paper<br />
cups)<br />
Pipee<br />
24mL Bromothymol blue soluon<br />
Parafilm<br />
6 Rubber bands<br />
Water*<br />
*You must provide<br />
90
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