# Cells and Systems

This worksheet helps you understand how cells work as the basic unit of life and how they organize into tissues, organs and systems ([Outcome](https://goa-cc-uat-aili-app-001.azurewebsites.net/explore/node/17320)). You will compare different types of cells, explore how materials move in and out of cells, and examine how body systems keep organisms healthy ([Outcome](https://goa-cc-uat-aili-app-001.azurewebsites.net/explore/node/17321)).

## Exercises

**1.** A student observes a plant cell and an animal cell under a microscope. Which of the following is found in the plant cell but NOT in the animal cell?

A) Cell membrane
B) Cell wall
C) Nucleus
D) Mitochondria

**2.** The diagram below shows the levels of organization in a multicelled organism. Match each level to its description ([Outcome](https://goa-cc-uat-aili-app-001.azurewebsites.net/explore/node/17320)).

| Level | Description |
|-------|-------------|
| Cell | A group of similar cells working together to perform a specific function |
| Tissue | The basic unit of life that carries out life processes |
| Organ | A structure made of different tissues that work together to perform a major function |

**3.** A single-celled amoeba and a grizzly bear are both living organisms, but they are very different. Explain one way they are similar and one way they are different ([Outcome](https://goa-cc-uat-aili-app-001.azurewebsites.net/explore/node/17320)).

Similarity: ___________________________________________________________

Difference: __________________________________________________________

**4.** Water moves into and out of cells through diffusion and osmosis. If a cell is placed in salt water with a higher concentration of salt outside the cell than inside, in which direction will water move?

A) Into the cell
B) Out of the cell
C) Both directions equally
D) Water will not move

**5.** Your heart rate increases when you exercise. Which body system is responsible for this change, and what is the purpose of this response ([Outcome](https://goa-cc-uat-aili-app-001.azurewebsites.net/explore/node/17321))?

Body system: _________________________________________________________

Purpose: _____________________________________________________________

**6.** Identify the roles of the following structures in supporting a healthy human body ([Outcome](https://goa-cc-uat-aili-app-001.azurewebsites.net/explore/node/17321)).

| Structure | Role |
|-----------|------|
| Lungs | _________________________ |
| Blood cells | _________________________ |
| Nerve cells | _________________________ |

## Answer Key

**1.** B) Cell wall

**2.** Cell = The basic unit of life that carries out life processes; Tissue = A group of similar cells working together to perform a specific function; Organ = A structure made of different tissues that work together to perform a major function

**3.** Similarity: Both are made of cells / Both are living things. Difference: An amoeba is single-celled while a grizzly bear is multicelled / An amoeba has no specialized organs while a bear does.

**4.** B) Out of the cell

**5.** Body system: Circulatory system (or cardiovascular system). Purpose: To deliver more oxygen and nutrients to muscles during exercise / To meet the body's increased energy demands.

**6.** Lungs: Exchange oxygen and carbon dioxide with the air; Blood cells: Transport oxygen and nutrients throughout the body; Nerve cells: Carry signals that allow the body to respond to stimuli.

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*AILI homework sheet · language en · model claude-haiku-4-5-20251001 · generated 2026-09-17 · id b0dd3177-a13e-4e30-87a9-a2d69bc78030*

### Sources

- node:n1: Sciences › Science (7–9) › Grade 8 › Unit B: Cells and Systems › Outcomes for Science, Technology and Society (STS) and Knowledge (https://goa-cc-uat-aili-app-001.azurewebsites.net/explore/node/17319)
- node:n2: Sciences › Science (7–9) › Grade 8 › Unit B: Cells and Systems › Outcomes for Science, Technology and Society (STS) and Knowledge (https://goa-cc-uat-aili-app-001.azurewebsites.net/explore/node/17320)
- node:n3: Sciences › Science (7–9) › Grade 8 › Unit B: Cells and Systems › Outcomes for Science, Technology and Society (STS) and Knowledge (https://goa-cc-uat-aili-app-001.azurewebsites.net/explore/node/17321)
- node:n4: Sciences › Science (7–9) › Grade 8 › Unit B: Cells and Systems › Outcomes for Science, Technology and Society (STS) and Knowledge (https://goa-cc-uat-aili-app-001.azurewebsites.net/explore/node/17320)
- node:n5: Sciences › Science (7–9) › Grade 8 › Unit B: Cells and Systems › Outcomes for Science, Technology and Society (STS) and Knowledge (https://goa-cc-uat-aili-app-001.azurewebsites.net/explore/node/17319)
- node:n6: Sciences › Science (7–9) › Grade 8 (https://goa-cc-uat-aili-app-001.azurewebsites.net/explore/node/17317)