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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 whic... 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 contain many alveoli, which significantly increase the surface area relative to the volume, allowing for more efficient gas exchange. These alveoli are lined with thin capillaries, facilitating the diffusion of gases like oxygen and carbon dioxide due to their close proximity to the blood supply. The lungs are also ventilated, ensuring that fresh oxygen is brought in while carbon dioxide is expelled, thus maintaining a concentration gradient that promotes continual diffusion. Additionally, the extensive capillary network surrounding the alveoli enhances the blood supply for effective oxygen uptake and carbon dioxide removal.
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Explain how the nitrate ions in Figure 13 are transported into the root hair cell.
Answer
The process by which nitrate ions are transported into the root hair cell is called active transport. This requires energy to move nitrate ions from a lower concentration in the soil to a higher concentration in the root hair cell against the concentration gradient.