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S1 Science: Plants and Photosynthesis (Paper 4 (error clinic))
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Tutor Prep Guide · Photosynthesis inputs and outputs, leaf structure, stomata and transpiration, and the iodine starch test
S1 Science: Plants and Photosynthesis (Paper 4 (error clinic))
This paper reworks the most common wrong answers, including soil as food, iodine testing glucose and photosynthesis only by day.
Direct answers The point of error clinic practice is not to redo the paper but to find which step went wrong.
01 Paper details (check answers afterwards)
| Item | Detail |
|---|---|
| Questions | 10 |
| Suggested time | 20 |
| Difficulty mix | Foundation 3 · Intermediate 3 · Challenge 3 · Error redo 1 |
| Chapter | Chapter: S1 Science: Plants and Photosynthesis |
| Level | S1 |
02 Questions (10 items)
- FoundationWhat are the raw materials of photosynthesis?
- FoundationWhat are the products of photosynthesis?
- FoundationInside which structure is chlorophyll found?
- IntermediateThe covered part of the leaf stays brownish after the iodine test. What does this show?
- IntermediateWhat is the purpose of boiling the leaf in alcohol before the starch test?
- IntermediateWhich part of the plant absorbs water?
- ChallengeWhich cells control the opening of stomata?
- ChallengeHow many molecules of water are needed for 6 molecules of carbon dioxide?
- ChallengeHow many glucose molecules can 24 carbon dioxide molecules make, and how much oxygen is released?
- Error redoA student answers that plants take in food from the soil. What is the correct statement?
03 Answers and one-line notes
| # | Answer | One-line note |
|---|---|---|
| 1 | Carbon dioxide and water | Light supplies the energy while the raw materials are carbon dioxide and water. |
| 2 | Glucose and oxygen | Glucose stores the energy and oxygen leaves through the stomata. |
| 3 | The chloroplast | The chloroplast is the site of photosynthesis and holds the chlorophyll. |
| 4 | Without light no starch can be made | That is the conclusion of the covering experiment and a common marking point. |
| 5 | To remove chlorophyll so the colour change can be seen clearly | Once the leaf is decolourised the blue black colour becomes visible. |
| 6 | The root, especially the root hairs | Root hairs increase the surface area and speed up absorption. |
| 7 | The guard cells | Guard cells swell as they take in water and the stoma opens. |
| 8 | 6 molecules | The equation balances both sides: 6CO2 plus 6H2O gives C6H12O6 plus 6O2. |
| 9 | 4 glucose molecules and 24 oxygen molecules | Dividing 24 by 6 gives 4, and each glucose releases 6 oxygen molecules. |
| 10 | The soil supplies only water and minerals, while food is made in the leaves by photosynthesis | This is the most common error in this topic, so keep absorption and manufacture apart. |
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.
For photosynthesis questions ask three things: whether all inputs are present (light, carbon dioxide, water), what the outputs are, and which condition the experiment changed.Tutor Registration →
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.