1. Name the part of a cell where aerobic respiration happens.
a) cytoplasm b) ribosome c) mitochondrion d) nucleus
Answer
c) mitochondrion
2. Write the word equation for anaerobic respiration in muscles.
a) glucose ➔ ethanol + carbon dioxide
b) glucose ➔ lactic acid
c) glucose ➔ carbon dioxide + water
d) glucose ➔ oxygen + energy
Answer
b) glucose ➔ lactic acid
3. What is "metabolism" ?
a) the breakdown of glucose only
b) the sum of all the reactions in a cell or the body
c) the process of aerobic respiration alone
d) the conversion of food into energy only
Answer
b) the sum of all the reactions in a cell or the body
4. Why anaerobic respiration transfers much less energy than aerobic respiration ?
a) because glucose is fully oxidised
b) because oxygen is not required
c) because carbon dioxide is not produced
d) because the oxidation of glucose is incomplete
Answer
d) because 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.
a) lipids b) starch c) amino acids d) cellulose
Answer
c) amino acids
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).