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IB Biology: Cells and Membrane Transport – Practice Paper 1 (10 Questions)
IB Biology: Cells and Membrane Transport – Practice Paper 1 (10 Questions)
Paper 1 covers magnification, the surface area to volume ratio and water potential: converting image and actual size, comparing diffusion in cells of different sizes, and using the sum of solute and pressure potentials to predict water movement.
Quick answer Magnification is image size over actual size after the units match. Surface area grows with the square of the edge and volume with the cube, so an edge of two gives a ratio of three and an edge of four only one point five.
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 |
02 Questions (10 items)
- FoundationA cell appears one hundred millimetres long under the microscope and is zero point one millimetres in reality. Find the magnification.
- FoundationA cell fifty micrometres wide measures five millimetres on a photograph. Find the magnification.
- FoundationA cubical cell has edges of two centimetres. Give its surface area, volume and surface area to volume ratio.
- FoundationCompare cubical cells with edges of four centimetres and one centimetre. Give each surface area to volume ratio.
- IntermediateA cell grows from an edge of two centimetres to four. How does the ratio change and what does it mean for diffusion?
- IntermediateA cell has a solute potential of minus four hundred kilopascals and a pressure potential of one hundred. Find its water potential.
- IntermediateCell A has a water potential of minus three hundred kilopascals and cell B minus five hundred. Which way does water move and why?
- ChallengeThe surrounding solution has a solute potential of minus zero point five megapascals and no pressure potential, while the cell is at minus zero point three. What happens to the cell?
- ChallengeThree cubical cells have edges of one, two and three centimetres. Which has the largest surface area to volume ratio and what is it?
- Error redoA student writes a water potential of minus five hundred kilopascals for minus four hundred plus a pressure potential of one hundred. What went wrong and what is correct?
03 Answers and one-line notes
| # | Answer | One-line note |
|---|---|---|
| 1 | the magnification is one thousand times | Image size divided by actual size gives one thousand. |
| 2 | the magnification is one hundred times | Convert to micrometres first, then divide five thousand by fifty. |
| 3 | surface area twenty-four, volume eight and a ratio of three to one | Six faces of four give twenty-four and the cube of two is eight. |
| 4 | the larger cell gives one point five and the smaller gives six | Surface area grows with the square of the edge but volume with the cube. |
| 5 | the ratio falls from three to one point five, so diffusion becomes less efficient | Volume grows eightfold while surface area only fourfold, so each unit of volume has less membrane. |
| 6 | the water potential is minus three hundred kilopascals | Water potential is the sum of the two components, giving minus three hundred. |
| 7 | from A to B, that is from higher to lower water potential | Minus three hundred is the higher value, so water leaves A for B. |
| 8 | the cell loses water and plasmolysis occurs | The outside is the lower water potential, so water leaves and the protoplast shrinks. |
| 9 | the smallest cell, with a ratio of six to one | The ratios are six, three and two, so the smallest cell wins. |
| 10 | the answer is minus three hundred; the student treated a positive pressure potential as negative | Pressure potential is positive in a living cell, so the sum is minus three hundred. |
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.
