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IB Biology: Cells and Membrane Transport – Practice Paper 4 (10 Questions)
IB Biology: Cells and Membrane Transport – Practice Paper 4 (10 Questions)
Paper 4 links magnification, surface area ratios and water potential, then closes with a sucrose experiment and carrier saturation, testing whether numbers can be turned into cell level conclusions.
Quick answer Ten times forty gives four hundred times magnification and eight millimetres becomes twenty micrometres, a solute potential of minus three hundred with a pressure potential of plus one hundred gives minus two hundred, and uptake rates of two, four, six and six show carrier saturation.
01 Paper details (check answers afterwards)
| Item | Detail |
|---|---|
| Questions | 10 questions |
| Suggested time | 25 minutes |
| Difficulty mix | Foundation 4 · Intermediate 3 · Challenge 2 · Error redo 1 |
| Chapter | Chapter: IB Biology: Cells and Membrane Transport – Tutor Lesson Plan |
| Level | IB SL/HL |
02 Questions (10 items)
- FoundationThe eyepiece is ten times and the objective forty times, and an image measures eight millimetres. What is the actual length?
- FoundationA cell sixty micrometres long is viewed at fifteen hundred times magnification. How large is the image?
- FoundationState three main differences between active transport and simple diffusion.
- FoundationA cell has a solute potential of minus three hundred kilopascals and a pressure potential of plus one hundred. What is its water potential?
- IntermediateCell A has a water potential of minus four hundred and fifty kilopascals and solution B minus six hundred and fifty. Which way does water move?
- IntermediateTwo cubes have sides of three centimetres and one centimetre. How many times larger is the surface area to volume ratio?
- IntermediateA cell at minus nine hundred kilopascals is placed in a solution of minus twelve hundred. What happens?
- ChallengeA cell has a solute potential of minus eleven hundred kilopascals and no pressure potential, while point five molar sucrose has a potential near minus twelve hundred and forty. What happens to the cell?
- ChallengeAs sugar concentration rises to zero point six molar, uptake rates are two, four, six and six. Why does the last step not rise?
- Error redoCommon error: water is said to move from the side with more solute to the side with less. What is correct?
03 Answers and one-line notes
| # | Answer | One-line note |
|---|---|---|
| 1 | Twenty micrometres | Total magnification is four hundred, so eight millimetres divided by four hundred is twenty micrometres. |
| 2 | Ninety millimetres | Sixty micrometres times fifteen hundred gives ninety thousand micrometres. |
| 3 | It needs carrier proteins, it needs ATP, and it can move against the concentration gradient | Simple diffusion follows the gradient, needs no energy and passes straight through the bilayer. |
| 4 | Minus two hundred kilopascals | Water potential is solute potential plus pressure potential. |
| 5 | From A to B, so cell A loses water | Water moves from the higher potential, minus four hundred and fifty, to the lower one. |
| 6 | Three times, two against six | The larger cube gives fifty-four over twenty-seven, the smaller six over one. |
| 7 | Water leaves the cell and plasmolysis occurs | The outside has the lower potential, so water leaves and the protoplast shrinks. |
| 8 | Water leaves and the cell plasmolyses because the external potential is lower | Minus eleven hundred is higher than minus twelve hundred and forty, so water flows out. |
| 9 | The carrier proteins are saturated, so the rate is limited by how many carriers exist | Active transport depends on carriers and ATP, and both are finite. |
| 10 | Water moves from the higher water potential, where solute is less concentrated, to the lower one | Water potential is the driving force and solute concentration is only one input to it. |
04 What to do after marking
- After marking, redo only the wrong items and write down which step went wrong (formula, unit, or misread number).
- Repeat the same item two days later; move to the next paper only when both attempts are correct.
- Parents only need the answer and note columns; there is no need to explain every item.
Questions and answers are written originally by the TutorZone team and are not taken from any school, publisher or examination authority paper. Every value is checked by computer.
