Year 7 Science · Unit 1 · Lesson 07
Challenge Worksheet
Learning Goals
Design a mini-experiment
A scientist wants to test: "Does the number of chloroplasts in a plant leaf cell change depending on how much light the plant receives?" Plan the investigation below.
| What I will change (independent variable) | |
| What I will keep the same (controlled variables — list at least 3) | |
| What I will measure (dependent variable) | |
| My prediction (what I expect to happen and why) | |
| How I would know if my prediction is wrong | |
| One limitation of this experiment |
1. When a plant loses too much water, its leaves and stem droop and wilt. Explain, using your knowledge of the large central vacuole, exactly why wilting happens. In your answer, describe how the vacuole normally keeps a plant firm, and what happens when water leaves the vacuole.
2. A scientist examines two plant cells from the same species: one taken from a sun-exposed leaf and one from a root growing underground. She predicts the leaf cell will have many more chloroplasts. Evaluate this prediction — is it correct? Explain why the number of chloroplasts would differ between these two cell types, linking your answer to the function of chloroplasts and the conditions each cell lives in.
Wrap Up
In one sentence, what was the main idea of this lesson?