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Yeast is a single-celled, microscopic fungus that uses sucrose as a food source - VCE - SSCE Biology - Question 1 - 2013 - Paper 1
Question 1
Yeast is a single-celled, microscopic fungus that uses sucrose as a food source. An experiment was carried out to investigate cellular respiration by a particular sp... show full transcript
Worked Solution & Example Answer:Yeast is a single-celled, microscopic fungus that uses sucrose as a food source - VCE - SSCE Biology - Question 1 - 2013 - Paper 1
Step 1
Ethanol levels rose as ethanol is a product of anaerobic respiration.
Answer
The increase in ethanol percentage from 0 to 4 indicates that anaerobic respiration occurred as a result of decreased oxygen levels. The initial oxygen level was 21%, and by the end of the experiment, it dropped to 18%. This decrease signifies that oxygen was utilized during the respiration process, which is essential for aerobic respiration. Since oxygen levels decreased and ethanol levels increased, this implies that anaerobic respiration was taking place.
Step 2
Prediction: CO2 is a product of (one of)
Answer
Increase in CO2 levels would be expected as a byproduct of both cellular respiration and anaerobic respiration. The correct answer in the context of this experiment would relate to cellular respiration, where CO2 is inherently a product formed during the metabolic processes.