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What is meant by the term diffusion? Molecules of carbon dioxide diffuse from the air into the mesophyll cells - AQA - GCSE Biology - Question 8 - 2020 - Paper 1
Question 8
What is meant by the term diffusion? Molecules of carbon dioxide diffuse from the air into the mesophyll cells. Which two changes will increase the rate at which... show full transcript
Worked Solution & Example Answer:What is meant by the term diffusion? Molecules of carbon dioxide diffuse from the air into the mesophyll cells - AQA - GCSE Biology - Question 8 - 2020 - Paper 1
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Explain how the human lungs are adapted for efficient exchange of gases by diffusion.
Answer
The human lungs are specially adapted for gas exchange through several features:
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Large Surface Area: The presence of many alveoli provides a large surface area relative to volume, facilitating a greater rate of gas exchange.
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Thin Walls: The alveoli and capillaries have thin walls, being only one cell thick, minimizing the distance gases must diffuse, thus speeding up the process.
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Proximity of Capillaries: Capillaries are closely associated with alveoli, ensuring oxygen from the alveoli can diffuse directly into the blood while carbon dioxide diffuses out of the blood into the alveoli.
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Efficient Ventilation: The mechanism of breathing actively moves air in and out of the lungs, maintaining high levels of oxygen and removing carbon dioxide efficiently.
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Concentration Gradient Maintenance: Breathing in fresh oxygen and exhaling carbon dioxide maintains a concentration gradient, which is crucial for diffusion to occur effectively.
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Explain how the nitrate ions in Figure 13 are transported into the root hair cell.
Answer
Nitrate ions need a different method of transport into the root hair cell because energy is required for this process. Specifically, active transport is utilized to move nitrate ions from a lower concentration in the soil to a higher concentration in the root hair cell, against the concentration gradient.