How plants make their own food

Science · Organisms & Life Processes · ages 11-12

Name ______________________ Date ____________

What two things does photosynthesis produce?
- Glucose and oxygen
- Carbon dioxide and water
- Chlorophyll and light
What are the two raw materials a plant uses to start photosynthesis?
- CO2 and water
- Soil and sunlight
- Oxygen and glucose
Chlorophyll is the substance in leaves that captures light energy for photosynthesis.
Circle one: True False
A fern's roots draw up water with dissolved minerals from the soil. Where does the fern get its carbon dioxide?
- From the soil, through its roots
- From the air, through its leaves
- From the water it absorbs
Which word equation correctly describes photosynthesis?
- Carbon dioxide + water, with light, makes glucose + oxygen
- Glucose + oxygen, with light, makes carbon dioxide + water
- Water + oxygen, with light, makes carbon dioxide + glucose
Farah wraps a leaf in foil for a week so no light reaches it. What happens to photosynthesis in that leaf?
- It speeds up
- It stops, because chlorophyll has no light energy to use
- It stops, because there's no carbon dioxide
A plant grows in a sealed glass jar with soil, water, and plenty of light, but the air inside can't be refreshed. What will most likely limit its growth over time?
- Running out of light
- Running out of water
- Running out of carbon dioxide in the sealed air
Tariq says, 'Plants eat minerals from the soil to make their food, just like animals eat food.' What's wrong with this idea?
- Minerals are the plant's actual food
- Plants build glucose from carbon dioxide and water using light. Minerals just keep the plant healthy
- Plants don't need minerals at all

Answer key

For grown-ups. Fold this page away before handing over the rest.

How plants make their own food W1-mt_zM5vu31jgl-s1

Glucose and oxygen · The products are a sugar called glucose and oxygen gas, released into the air.
CO2 and water · Plants pull carbon dioxide from the air and water from the soil to build glucose.
True · Chlorophyll sits inside chloroplasts and absorbs light, giving leaves their green color.
From the air, through its leaves · Leaves have tiny openings that let carbon dioxide in from the air, separate from what the roots collect.
Carbon dioxide + water, with light, makes glucose + oxygen · Photosynthesis starts with carbon dioxide and water and, powered by light, produces glucose and oxygen.
It stops, because chlorophyll has no light energy to use · Chlorophyll needs light to power the reaction. No light means no energy source, even if carbon dioxide is still there.
Running out of carbon dioxide in the sealed air · Even with light and water steady, a plant needs a fresh supply of carbon dioxide, one of the two raw materials, to keep making glucose.
Plants build glucose from carbon dioxide and water using light. Minerals just keep the plant healthy · Minerals support growth and health, but a plant's food, glucose, comes from carbon dioxide and water combined with light energy.