1. Name the part of a cell where aerobic respiration happens.
Answer
Mitochondrion (or mitochondria).
2. Write the word equation for anaerobic respiration in muscles.
Answer
glucose ➔ lactic acid
3. What is "metabolism" ?
Answer
Metabolism is the sum of all the reactions in a cell or the body.
4. Give the reason why anaerobic respiration transfers much less energy than aerobic respiration.
Answer
The oxidation of glucose is incomplete.
5. The athlete's heart rate and breathing rate remain high after the sprint because the athlete has an oxygen debt. Explain what is meant by an "oxygen debt".
Answer
An oxygen debt is the amount of extra oxygen needed after exercise to react with the accumulated lactic acid and remove it from the cells.
6. Explain how an increase in heart rate helps a person to exercise.
Answer
The increase in heart rate supplies more oxygenated blood to the muscles, allowing greater aerobic respiration and releasing more energy for muscle contraction.
7. Name the molecule that can be synthesised from glucose and nitrate ions.
Answer
Amino acids and proteins can be synthesised from glucose and nitrate ions.
8. The figure below shows the metabolic rate at different ages for males and females. Compare the mean metabolic rates of females and males at different ages.
Answer
The mean metabolic rate of males is higher than females at all ages. The metabolic rates of both females and males decreases with age. The metabolic rates of both females and males decreases rapidly up to about 20 years of age, then decreases more slowly.
9. The figure below shows the apparatus a student used to investigate the effect of temperature on the rate of anaerobic respiration in yeast. Explain how the student could use the apparatus to measure the rate of respiration.
Answer
Count the number of bubbles, or collect the carbon dioxide gas released and measure its volume in one minute (or another specified time).