In three different experiments, the reaction tube initially contained the following:
1 - VCE - SSCE Biology - Question 4 - 2016 - Paper 1
Question 4
In three different experiments, the reaction tube initially contained the following:
1. suspension of mitochondria
2. cytosol of cells from which the mitochondria ha... show full transcript
Worked Solution & Example Answer:In three different experiments, the reaction tube initially contained the following:
1 - VCE - SSCE Biology - Question 4 - 2016 - Paper 1
Step 1
Experiment 1 – Suspension of mitochondria
Substance added: glucose
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Answer
When glucose is added, there is no change in oxygen concentration because glucose is not metabolized (broken down) by the mitochondria.
Step 2
Experiment 1 – Suspension of mitochondria
Substance added: pyruvate
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Answer
With the addition of pyruvate, the oxygen concentration decreases as pyruvate is a substrate of the Krebs cycle.
Step 3
Experiment 2 – Cytosol of cells from which the mitochondria had been removed
Substance added: glucose
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Answer
In this case, when glucose is added, there is no change in oxygen concentration. Glycolysis is anaerobic (or glucose is converted to pyruvate but no mitochondria so oxygen is not used).
Step 4
Experiment 2 – Cytosol of cells from which the mitochondria had been removed
Substance added: pyruvate
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Answer
With pyruvate added, there is no change in oxygen concentration because there is no aerobic breakdown of pyruvate.
