Practise 41 real questions on Cells, osmosis and transport across membranes from 2021 to 2026. See the answer and explanation as soon as you answer.
Cells, osmosis and transport across membranes is one of the 13 main topics in our O Level Biology (Cambridge (CAIE) 5090) question bank, and about 7% of its real questions come from it. Tayyari Karo has 41 real questions on this topic from 2021 to 2026, from Paper 1, Paper 3, Paper 4; 32 are multiple choice and marked instantly, and the rest are structured questions with a model answer. By difficulty: 31 medium, 9 easy, 1 hard.
Work through the questions below, then open the explanation for each one. Redo the ones you missed a few days later.
These are real past-paper questions. Think of your answer first, then open the explanation.
Human liver cells contain, on average, 1500 mitochondria per cell. The volume of a typical liver cell is 11 305 µm3 and mitochondria occupy 20% of this volume. What is the average volume of a single liver cell mitochondrion?
Answer: B. 1.5 µm3
20% of 11 305 = 2261 µm3; 2261 / 1500 = about 1.5 µm3.
Some features of cell division are listed: 1 sometimes called reduction division; 2 used in asexual reproduction; 3 used in the cell division of stem cells; 4 results in the production of haploid cells; 5 sometimes produces a cancer. Which of these are features of meiosis?
Answer: B. 1 and 4 only
Meiosis is the reduction division producing haploid gametes; the other features belong to mitosis.
Which statement about nuclear division is correct?
Answer: B. Meiosis results in genetically different daughter cells.
Meiosis produces genetically varied gametes; mitosis produces two identical diploid cells.
Contact lenses are partially permeable and stored in a sodium chloride solution with the same concentration as eye fluid. A person stores them in distilled water by mistake, then places a lens on the eye. Which pair of statements describes what happens? 1 Water from eye fluid enters lens by osmosis. 2 Water leaves lens and enters eye fluid by osmosis. 3 The lens shrinks. 4 The lens swells.
Answer: C. 2 and 3
Animal cells burst in distilled water but plant cells do not. Which statement explains this?
Answer: D. The cell wall of plant cells resists turgor pressure.
The plant cell wall resists the inward pressure of turgor, preventing bursting.
Which row identifies how ions and molecules move by active transport? (against the concentration gradient / down the concentration gradient / through a membrane / requiring energy)
Answer: A. against: yes / down: no / through membrane: yes / requiring energy: yes
| Session | Paper 1 | Paper 3 | Paper 4 |
|---|---|---|---|
| May/June 2026 | 5 | – | – |
| May/June 2025 | 7 | – | – |
| Oct/Nov 2025 | 3 | – | – |
| May/June 2024 | 2 | – | – |
| Oct/Nov 2024 | 3 | – | – |
| May/June 2023 | 1 | 1 | – |
| Oct/Nov 2023 | 3 | 1 | 1 |
| May/June 2022 | 1 | – | – |
| Oct/Nov 2022 | 4 | 1 | 1 |
| May/June 2021 | 1 | – | – |
| Oct/Nov 2021 | 2 | 2 | 2 |
41 real O Level Biology (5090) questions on Cells, osmosis and transport across membranes from 2021 to 2026, from Paper 1, Paper 3, Paper 4. Each one shows the year, session and paper it came from.
Yes. Every question shows the correct answer and a short explanation the moment you answer.
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