RespirationCambridge IGCSE Biology: Topic test

20 questions, 54 marks

Cambridge IGCSE Biology

Respiration topic test

Total 54 marks

Name

Class

Date

1
A biology teacher listed several processes occurring inside the cells of a growing seedling: cell division to produce new cells, active transport of mineral ions into the roots, and protein synthesis to build new enzymes, all needing a continual supply of energy from respiration, alongside the passive diffusion of water into root hair cells by osmosis.
(a)
Which of the following processes taking place in the seedling does NOT require energy released directly by respiration?
[1 mark]
Aactive transport of mineral ions into the root
Bprotein synthesis
Ccell division
Ddiffusion of water into root hair cells by osmosis
(b)
What is aerobic respiration?
[1 mark]
Athe chemical reactions in cells that break down nutrient molecules without using oxygen
Bthe chemical reactions in cells that use oxygen to break down nutrient molecules, releasing energy
Cthe process by which plants absorb carbon dioxide from the air
Dthe process by which cells divide to produce new cells
(c)
State two uses, other than active transport, of the energy released by respiration in a growing seedling's cells.
[2 marks]
Total for question 1: 4 marks
2
A student wrote out the equations that summarise aerobic respiration in a muscle cell, in order to revise for an exam on cellular respiration.
(a)
What is the correct word equation for aerobic respiration?
[1 mark]
Aglucose + oxygen → carbon dioxide + water
Bglucose → carbon dioxide + water
Cglucose + oxygen → alcohol + carbon dioxide
Dglucose → lactic acid
(b)
Which of the following is the correctly balanced chemical equation for aerobic respiration?
[1 mark]
AC6H12O6 → 2C2H5OH + 2CO2
BC6H12O6 + O2 → CO2 + H2O
CC6H12O6 + 6O2 → 6CO2 + 6H2O
DC6H12O6 → 6CO2 + 6H2O
(c)
Explain what the number '6' in front of O2, CO2 and H2O in the balanced equation for aerobic respiration represents.
[2 marks]
Total for question 2: 4 marks
3
A brewer mixed yeast with a sugar solution in a sealed container with no oxygen present, so that the yeast respired anaerobically, producing alcohol and carbon dioxide gas over several hours.
(a)
Write the word equation for anaerobic respiration in yeast, and explain why sealing the container prevents the yeast from instead respiring aerobically.
[3 marks]
(b)
Explain why anaerobic respiration in yeast releases much less energy per glucose molecule than aerobic respiration would, and explain why the yeast might still need to break down a large total amount of glucose to meet its energy needs.
[4 marks]
Total for question 3: 7 marks
4
A rower performed a maximal, all-out 500-metre effort on a rowing machine lasting less than two minutes; during the effort their leg and arm muscles worked far harder than their circulatory and breathing systems could supply oxygen for, and afterwards the rower continued breathing heavily with a raised heart rate for several minutes while recovering.
(a)
Explain why the rower's muscles respired anaerobically during the maximal effort, and explain the consequences of this for their muscles, including the word equation for anaerobic respiration in muscle cells.
[6 marks]
(b)
Explain, referring to the rower's heart rate and breathing after the effort, how their body removes the lactic acid produced during the maximal effort and repays the oxygen debt.
[6 marks]
Total for question 4: 12 marks
5
A doctor explained that shivering when cold involves rapid, repeated muscle contractions that release heat, helping the body to maintain a constant internal body temperature, and that this shivering response, and the nerve impulses controlling it, requires a continual supply of energy from respiration.
(a)
Which of the following requires energy released by respiration?
[1 mark]
Athe diffusion of oxygen from the air into the alveoli
Bthe diffusion of carbon dioxide out of the blood at the alveoli
Cthe passive movement of water by osmosis
Dmuscle contraction during shivering
(b)
Why does shivering help to maintain body temperature when a person is cold?
[1 mark]
Amuscle contractions during shivering release heat as a by-product of the increased respiration needed to power them
Bshivering directly increases the amount of oxygen in the blood
Cshivering reduces the rate of respiration
Dshivering converts glucose directly into water
(c)
State two further uses of energy released by respiration in the human body, other than muscle contraction and the passage of nerve impulses.
[2 marks]
Total for question 5: 4 marks
6
A winemaker sealed crushed grape juice, containing natural sugars, together with yeast in an airtight vessel for several weeks, allowing the yeast to convert the sugars into alcohol without any oxygen present.
(a)
Which balanced chemical equation correctly represents anaerobic respiration in the yeast used by the winemaker?
[1 mark]
AC6H12O6 + 6O2 → 6CO2 + 6H2O
BC6H12O6 → 2C2H5OH + 2CO2
CC6H12O6 → 6CO2 + 6H2O
DC6H12O6 + O2 → C2H5OH + CO2
(b)
Why is an airtight vessel used during this process?
[1 mark]
Ato increase the temperature of the mixture
Bto allow more carbon dioxide to enter the mixture
Cto prevent oxygen reaching the yeast, so it respires anaerobically
Dto prevent the sugars from dissolving
(c)
Explain why gas bubbles were observed escaping from the sealed vessel during fermentation.
[2 marks]
Total for question 6: 4 marks
7
A scientist investigated the effect of temperature on the rate of aerobic respiration in a culture of yeast cells suspended in a glucose solution, measuring the rate of carbon dioxide production at temperatures of 10, 20, 30 and 40 degrees Celsius, and again at 50 degrees Celsius.
(a)
Describe how you would expect the rate of respiration to change as the temperature increases from 10°C to around 40°C, and explain this trend.
[3 marks]
(b)
Explain what would most likely happen to the rate of respiration if the temperature were increased further, to 50°C, and explain why.
[4 marks]
Total for question 7: 7 marks
8
An athlete ran a long-distance race at a steady pace for over an hour, staying well within their aerobic capacity throughout, before sprinting flat out for the final 100 metres to the finish line, during which their leg muscles worked far harder than oxygen could be supplied to them.
(a)
Explain the differences between the respiration taking place in the athlete's muscles during the steady, long-distance part of the race and during the final sprint, including the word equation for each type of respiration and the amount of energy released.
[6 marks]
(b)
Explain what this energy, released by respiration, would have been used for in the athlete's muscle cells throughout the race, and explain how the athlete's body would recover from the oxygen debt built up during the final sprint.
[6 marks]
Total for question 8: 12 marks

End of questions