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: Change in oxygen concentration for glucose
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Answer
When glucose is added, there is no change in oxygen concentration. This indicates that glucose is not metabolized or broken down by the mitochondria.
Step 2
Experiment 1 – Suspension of mitochondria: Change in oxygen concentration for pyruvate
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Answer
When pyruvate is added, there is a decrease in the oxygen concentration. This decrease is explained as pyruvate is a substrate of the Krebs cycle, where oxygen is utilized.
Step 3
Experiment 2 – Cytosol of cells from which the mitochondria had been removed: Change in oxygen concentration for glucose
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Answer
In this experiment, when glucose is added, there is no change in oxygen concentration. This is due to the fact that glycolysis takes place, converting glucose to pyruvate, but without mitochondria, no oxygen is used.
Step 4
Experiment 2 – Cytosol of cells from which the mitochondria had been removed: Change in oxygen concentration for pyruvate
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Answer
After adding pyruvate, there is no change in oxygen concentration. This indicates that there is no aerobic breakdown of pyruvate occurring in the cytosol as there are no mitochondria present.
