A technician adds equal masses of glucose to two cultures of animal skin cells. Oxygen is supplied to culture P, in which glucose reacts according to the equation C6H12O6+6O2→6CO2+6H2O\text{C}_6\text{H}_{12}\text{O}_6 + 6\text{O}_2 \rightarrow 6\text{CO}_2 + 6\text{H}_2\text{O}C6H12O6+6O2→6CO2+6H2O. In culture Q, oxygen is absent and glucose is converted to lactic acid.
Which option correctly interprets how much chemical energy remains in the products after the glucose has been used?
The same amount of chemical energy remains in both cultures because equal masses of glucose are used
More chemical energy remains in culture Q because lactic acid results from incomplete breakdown of glucose
More chemical energy remains in culture P because oxygen contributes energy to the products
No chemical energy remains in either culture because respiration transfers it all to the cells
92 exam-style questions on AQA GCSE Biology 4.2 Respiration, covering 4.2.1 Aerobic and anaerobic respiration, 4.2.2 Response to exercise, and 4.2.3 Metabolism. Each one has a worked solution and a mark scheme showing where the marks go.