# Cells and Systems

Students investigate the structures and functions of cells and body systems, and describe how different organisms meet similar needs through varied structures ([Outcome](https://goa-cc-uat-aili-app-001.azurewebsites.net/explore/node/17319), [Outcome](https://goa-cc-uat-aili-app-001.azurewebsites.net/explore/node/17320)). You will examine how cells work together in tissues and organs, and explain how body systems respond to changes in the environment ([Outcome](https://goa-cc-uat-aili-app-001.azurewebsites.net/explore/node/17321)).

## Exercises

**1. Single-celled and multicelled organisms**

An amoeba is a single-celled organism. A grizzly bear is a multicelled organism. Both organisms need to gather food and respond to their environment.

Identify one similarity and one difference between these organisms in how they meet these needs.

Similarity: _______________________________________________________________

Difference: ________________________________________________________________

**2. Plant and animal cells**

The table below shows structures found in different cell types. Place an X in each cell to show whether the structure is found in plant cells, animal cells, or both.

| Structure | Plant cells | Animal cells |
|---|---|---|
| Cell membrane | | |
| Cell wall | | |
| Nucleus | | |
| Chloroplast | | |

**3. Movement of materials into cells**

Water moves into and out of cells through diffusion and osmosis. This movement depends on the concentration of dissolved materials on either side of the cell membrane.

Which statement correctly describes why water moves across a cell membrane?

A) Water moves from where there is more water to where there is less water.

B) Water moves because the cell membrane pumps it across.

C) Water moves only into cells, never out.

D) Water moves because the cell uses energy to transport it.

**4. Organs and tissues in the human body**

The lungs are organs that work with other structures to help your body exchange gases. Name the gas that the lungs take in from the air and the gas that the lungs release into the air.

Gas taken in: ________________________________________________________________

Gas released: ________________________________________________________________

**5. Body systems responding to stimuli**

You are running a race. Your heart rate increases during the race and returns to normal afterward.

Explain why your heart rate increases during exercise.

_____________________________________________________________________________

_____________________________________________________________________________

**6. Research and human health**

Scientists have developed vaccines to prevent certain diseases. Vaccines work by helping the immune system recognize harmful pathogens before they cause illness.

Which of the following best describes how vaccine research has improved human health?

A) Vaccines eliminate all bacteria and viruses from the environment.

B) Vaccines allow people to avoid getting sick from certain diseases.

C) Vaccines replace the need for a healthy immune system.

D) Vaccines cure diseases after a person becomes ill.

## Answer Key

1. Similarity: Both need to take in food and sense changes in their surroundings. Difference: An amoeba is one cell that does all these tasks; a grizzly bear has many specialized cells organized into tissues and organs that perform these functions.

2. Cell membrane: Plant X, Animal X; Cell wall: Plant X, Animal blank; Nucleus: Plant X, Animal X; Chloroplast: Plant X, Animal blank.

3. A

4. Gas taken in: oxygen; Gas released: carbon dioxide.

5. During exercise, your muscles need more oxygen and nutrients. Your heart beats faster to pump blood more quickly to deliver oxygen and nutrients to your muscles and remove waste products like carbon dioxide.

6. B

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*AILI homework sheet · language en · model claude-haiku-4-5-20251001 · generated 2026-09-17 · id 8b393530-dfa2-4490-af1b-5b6e204c38cd*

### Sources

- node:n1: Unit B: Cells and Systems (https://goa-cc-uat-aili-app-001.azurewebsites.net/explore/node/17317)
- node:n2: Outcomes for Science, Technology and Society (STS) and Knowledge (https://goa-cc-uat-aili-app-001.azurewebsites.net/explore/node/17318)
- node:n3: *Students will:* Investigate living things; and identify and apply scientific ideas used to interpret their general stru (https://goa-cc-uat-aili-app-001.azurewebsites.net/explore/node/17319)
- node:n4: *Students will:* Investigate and describe the role of cells within living things - describe the role of cells as a basic (https://goa-cc-uat-aili-app-001.azurewebsites.net/explore/node/17320)
- node:n5: Students will: Interpret the healthy function of human body systems, and illustrate ways the body reacts to internal and (https://goa-cc-uat-aili-app-001.azurewebsites.net/explore/node/17321)
- node:n6: *Students will:* Describe areas of scientific investigation leading to new knowledge about body systems and to new medic (https://goa-cc-uat-aili-app-001.azurewebsites.net/explore/node/17322)
- node:n7: Skill Outcomes (https://goa-cc-uat-aili-app-001.azurewebsites.net/explore/node/17323)
- node:n8: Specific Outcome (https://goa-cc-uat-aili-app-001.azurewebsites.net/explore/node/17324)