Key learning points

1. Process data to calculate the volume of gas collected in the measuring cylinder, and the mean of repeat measurements.
2. Calculate the rate of respiration by dividing the volume of gas collected in the measuring cylinder by the time.
3. Use appropriate units for the rate of cellular respiration.
4. Compare the rate of respiration in yeast given different substrates, and describe trends in the data.
5. Use ideas about enzymes and active sites to explain the effect of different substrates on the rate of respiration.

Keywords

• Rate - A measure of how much change occurs per unit of time.

• Cellular respiration - An exothermic chemical process that transfers energy for life processes, using glucose as fuel.

• Substrate - The substance that fits into an enzyme’s active site.

• Enzyme - A biological catalyst.

• Active site - The part of an enzyme where the substrate binds.

Common misconception