Neco Model Questions Vol1 2025 Biology Question 42

Practice objective / multiple choice question 42 from the 2025 Neco Model Questions Vol1 Biology examination.

Neco Model Questions Vol1 2025 Biology Objective / Multiple Choice Medium Difficulty
Question 42 NECO_MODEL_QUESTIONS_VOL1 • 2025 • BIOLOGY • objective

A leaf cell has a semi‑permeable membrane of total surface area \(1500\ \mu\text{m}^2\). The diffusion coefficient for CO₂ in the cytoplasm is \(2.0\times10^{-5}\ \text{cm}^2\text{s}^{-1}\). The concentration difference of CO₂ across the membrane is \(0.04\ \text{mol cm}^{-3}\) and the membrane thickness is \(1\ \mu\text{m}\). (a) Using Fick's first law \(J = -D\frac{\Delta C}{\Delta x}A\), calculate the rate of CO₂ diffusion (in mol s\(^{-1}\)). (b) If the cell increases its membrane surface area by 20 % while all other conditions remain the same, what is the new diffusion rate?

Answer Options

A. Initial rate = \\(1.2\\times10^{-7}\\ \text{mol s}^{-1}\\); after 20 % increase = \\(1.5\\times10^{-7}\\ \text{mol s}^{-1}\\).
B. Initial rate = \\(1.2\\times10^{-6}\\ \text{mol s}^{-1}\\); after 20 % increase = \\(1.44\\times10^{-6}\\ \text{mol s}^{-1}\\).
C. Initial rate = \\(1.0\\times10^{-7}\\ \text{mol s}^{-1}\\); after 20 % increase = \\(1.2\\times10^{-7}\\ \text{mol s}^{-1}\\).
Correct Answer D. Initial rate = \(1.2\times10^{-7}\ \text{mol s}^{-1}\); after 20 % increase = \(1.44\times10^{-7}\ \text{mol s}^{-1}\).
Correct Answer
D
Correct Option:
Initial rate = \(1.2\times10^{-7}\ \text{mol s}^{-1}\); after 20 % increase = \(1.44\times10^{-7}\ \text{mol s}^{-1}\).

About This Question

This is Neco Model Questions Vol1 2025 Biology Question 42. It is one of the objective questions from the 2025 Neco Model Questions Vol1 Biology examination.

Difficulty level: Medium .

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