Answer the following questions in relation to an investigation you carried out into fermentation by yeast cells - Leaving Cert Biology - Question b - 2013
Question b
Answer the following questions in relation to an investigation you carried out into fermentation by yeast cells.
(i) Explain what is meant by anaerobic respiration.... show full transcript
Worked Solution & Example Answer:Answer the following questions in relation to an investigation you carried out into fermentation by yeast cells - Leaving Cert Biology - Question b - 2013
Step 1
Explain what is meant by anaerobic respiration.
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Answer
Anaerobic respiration is a metabolic process in which organisms convert glucose into energy without the presence of oxygen. During this process, energy is released from food and used to fuel cellular activities. In the case of yeast, the fermentation process results in the production of alcohol and carbon dioxide.
Step 2
Where in the cell does anaerobic respiration occur?
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Anaerobic respiration occurs in the cytoplasm of the cell.
Step 3
Describe, with the aid of a diagram, how you kept the yeast under anaerobic conditions during the investigation.
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To keep the yeast under anaerobic conditions, the setup includes a sealed container filled with the yeast mixture. A diagram can be illustrated showing:
A flask containing yeast and sugar.
An airlock or tube that delivers gas into a liquid (such as oil) to prevent air from entering.
The flask sealed tightly to prevent any oxygen from getting in. This ensures that the fermentation process can occur without oxygen.
Step 4
Name the two substances produced by the yeast in the process of fermentation.
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The two substances produced by the yeast during fermentation are ethanol (alcohol) and carbon dioxide (CO₂).
Step 5
How did you know that fermentation had ceased?
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Fermentation can be observed to have ceased when bubbling in the mixture stops, indicating that carbon dioxide is no longer being produced.
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