Edexcel Biology Gcse - Exchange and Transport in Animals Sample Exam Questions and Answers
Gas exchange in the lungs takes place in the alveoli, which are tiny air sacs surrounded by capillaries. Oxygen diffuses from the alveoli into the blood, while carbon dioxide diffuses from the blood into the alveoli to be exhaled.
Where does gas exchange take place in the lungs? [1 mark]
Alveolus
Key Terms
Where does gas exchange take place in the lungs? [1 mark]
Alveolus
Oxygen is involved with aerobic respiration in cells.
What is the equation for aerobic respiration?
glucose + oxygen → carbon dioxide + water
A person had emphysema. This reduces the number of alveoli in the lungs.
Explain how emphysema would affect the amount of oxygen carried in the bloodstream. [2 marks]
emphysema will reduce the amount of oxygen carried into the bloodstream
because there is reduced alveoli, which are the gas exchange surface ...
Give one reason why it is important that human lungs have a high surface area to volume ratio. [1 mark]
To maximise gas exchange/maximise oxygen uptake
Give one reason why the wall of the left ventricle of the heart is thicker than the right. [1 mark]
To pump blood around the body under higher pressure
Valves in the human heart may become damaged and no longer function.
Describe what would happen to the flow of blood in the left side of the heart if the valve between the left atrium and ventricle did not function effectively. [2 marks]
blood would flow backwards from the ventricle to the atrium/blood will leak through
less (oxygenated) blood would be pumped to the body
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| Term | Definition |
|---|---|
Where does gas exchange take place in the lungs? [1 mark] | Alveolus |
Oxygen is involved with aerobic respiration in cells. What is the equation for aerobic respiration? | glucose + oxygen → carbon dioxide + water |
A person had emphysema. This reduces the number of alveoli in the lungs. Explain how emphysema would affect the amount of oxygen carried in the bloodstream. [2 marks] | emphysema will reduce the amount of oxygen carried into the bloodstream because there is reduced alveoli, which are the gas exchange surface between the lungs and blood capillaries |
Give one reason why it is important that human lungs have a high surface area to volume ratio. [1 mark] | To maximise gas exchange/maximise oxygen uptake |
Give one reason why the wall of the left ventricle of the heart is thicker than the right. [1 mark] | To pump blood around the body under higher pressure |
Valves in the human heart may become damaged and no longer function. Describe what would happen to the flow of blood in the left side of the heart if the valve between the left atrium and ventricle did not function effectively. [2 marks] | blood would flow backwards from the ventricle to the atrium/blood will leak through less (oxygenated) blood would be pumped to the body |
Calculate the rate of oxygen consumption per second for the results in respirometer A. [2 marks] | 2.4 ÷ (30 × 60) = 0.0013 ml/second Or 1.6 ÷ (20 × 60) = 0.0013 ml/second Or 0.8 ÷ (10 × 60) = 0.0013 ml/second |
Describe how the circulatory system transports substances around the body. [6 marks] | the heart/ventricle pumps blood blood passes through blood vessels/arteries/veins/capillaries the blood travels to the lungs and then to the rest of the body arteries transport blood away from the heart veins transport blood to the heart valves prevent backflow capillaries exchange materials with tissues/cells red blood cells carry oxygen plasma transports nutrients/waste/hormones |
A reduced cardiac output would affect the performance of an athlete. Explain the effects that a reduced cardiac output would have on the muscle cells of an athlete. [6 marks] | there will less blood flow (to the muscles) less blood leaves the heart less oxygen reaches muscle less glucose reaches muscle reduced rate of aerobic respiration less energy released less carbon dioxide removed greater rate of anaerobic respiration glucose broken down without oxygen reduced muscle contraction build up of lactic acid in muscle cells -lactic acid causes cramp/fatigue |
Describe how digested food molecules move from the small intestine to the heart. [2 marks] | A description linking two of the following things: food molecules are absorbed/diffuse into blood/plasma into capillaries in veins (to the heart) |
Yeast use both aerobic and anaerobic respiration to release energy. Which organelle in the yeast cell is the site of aerobic respiration? [1 mark] | mitochondrion/mitochondria |
Yeast use both aerobic and anaerobic respiration to release energy. The word equation for anaerobic respiration in yeast is: glucose → alcohol + carbon dioxide Describe how aerobic respiration is different from anaerobic respiration in yeast. [2 marks] | A description including any two from the following: Aerobic respiration: uses oxygen produces water releases more energy does not produce/release alcohol anaerobic respiration occurs in the cytoplasm |