Answers to AQA GCSE Respiration (Biology)

Practice Questions

1.State where respiration occurs

In every living cell

2.Summarise the differences between aerobic and anaerobic respiration

FeatureAerobic RespirationAnaerobic Respiration
Oxygen neededYesNo
LocationIn mitochondriaIn cytoplasm
Word equationGlucose + oxygen → carbon dioxide + waterAnimals:Glucose → lactic acid
Plants & yeast: Glucose → ethanol + carbon dioxide
ProductsCarbon dioxide and waterLactic acid (animals)
Ethanol and carbon dioxide (plants and yeast)
Energy transferredLarge amount of energySmall amount of energy
Breakdown of glucoseComplete breakdownIncomplete breakdown
When it happensNormal conditions when oxygen is presentWhen oxygen supply is limited e.g. during intense exercise
Effect on musclesNo oxygen debtOxygen debt builds up

3. Under what conditions will animals carry out anaerobic respiration.

During intense exercise when oxygen cannot be delivered quickly enough to muscle cells, then anaerobic respiration will occur.