4.5 Aerobic and anaerobic respiration
6 exam questions worth 10 marks. Write your answer, open the mark scheme, then give yourself the marks you earned. Your answers are saved on this device.
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Write the word equation for aerobic respiration.
Mark scheme
- glucose + oxygen (1)
- → carbon dioxide + water (1)
Model answer
glucose + oxygen → carbon dioxide + water
Give two ways the body uses the energy transferred by respiration.
Mark scheme
Any two from:
- muscle contraction / movement (1)
- chemical reactions to build larger molecules (1)
- keeping warm / body temperature (1)
- active transport (1)
Model answer
For muscle contraction and to build larger molecules, such as proteins.
What are the products of anaerobic respiration in yeast?
Choose one answer.
Correct Not quite: the answer is Ethanol and carbon dioxide
Mark scheme
D
Model answer
D: ethanol and carbon dioxide.
Explain why anaerobic respiration releases less energy than aerobic respiration.
Mark scheme
- glucose is not completely broken down / oxidised (1)
- products (lactic acid / ethanol) still contain energy (1)
Model answer
In anaerobic respiration the glucose is only partly broken down, so the lactic acid or ethanol made still contains a lot of energy.
Explain how yeast makes bread dough rise.
Mark scheme
- yeast respires anaerobically / ferments (sugar) (1)
- producing carbon dioxide (gas) which makes the dough rise (1)
Model answer
Yeast respires anaerobically, which is fermentation, producing carbon dioxide gas that forms bubbles in the dough and makes it rise.
Respiration is described as exothermic. What does this mean?
Mark scheme
energy is transferred / released to the surroundings
Model answer
Energy is transferred from the reaction to the surroundings.
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