Igcse Model Questions Vol1 2022 Biology Question 24
Practice objective / multiple choice question 24 from the 2022 Igcse Model Questions Vol1 Biology examination.
A small gas diffuses across a cell membrane that is \(5\) µm thick. The diffusion coefficient for the gas in the cytoplasm is \(2.5 \times 10^{-5}\) cm\(^2\)·s\(^{-1}\). Using the approximation \(t = \frac{x^{2}}{2D}\), where \(x\) is the diffusion distance and \(D\) the diffusion coefficient, calculate the time required for the gas to cross the membrane (in seconds).\n\nAn active transport protein can move the same amount of this gas at a rate of \(1 \times 10^{-8}\) mol·s\(^{-1}\). If the cell needs to transport \(1 \times 10^{-9}\) mol of the gas, how long will active transport take (in seconds)?\n\nWhich mechanism delivers the required amount of gas faster?
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This is Igcse Model Questions Vol1 2022 Biology Question 24. It is one of the objective questions from the 2022 Igcse Model Questions Vol1 Biology examination.
Difficulty level: Medium .
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