Biology: Photosynthesis and Respiration Worksheet

Question 1

Plants use sunlight, water, and carbon dioxide to make sugar and oxygen. What is this process called?

Accepted Answer

This process is called photosynthesis. During photosynthesis, plants use sunlight to make their own food.

Question 2

Write the three main things a plant needs for photosynthesis.

Accepted Answer

A plant needs sunlight, water, and carbon dioxide for photosynthesis. These materials help the plant make sugar for food.

Question 3

What gas do plants release during photosynthesis that animals need to breathe?

Accepted Answer

Plants release oxygen during photosynthesis. Animals need oxygen to breathe and release energy from food.

Question 4

A student covers one leaf on a plant with dark paper and leaves another leaf uncovered. After a day in sunlight, which leaf will make more sugar? Explain why.

Accepted Answer

The uncovered leaf will make more sugar because it can receive sunlight. The covered leaf gets little or no light, so it cannot do as much photosynthesis.

Question 5

Cellular respiration is how living things release energy from sugar. What two things are usually needed for cellular respiration?

Accepted Answer

Cellular respiration usually needs sugar and oxygen. Cells use them to release energy for the living thing.

Question 6

Circle the statement that is true: A) Only animals do respiration. B) Plants and animals both do respiration. Explain your choice.

Accepted Answer

Statement B is true because both plants and animals do cellular respiration. Plants make sugar during photosynthesis, but they also use sugar for energy through respiration.

Question 7

Complete this word equation for photosynthesis: carbon dioxide + water + light energy makes blank + oxygen.

Accepted Answer

Carbon dioxide + water + light energy makes sugar + oxygen. The sugar stores energy that the plant can use later.

Question 8

Complete this word equation for respiration: sugar + oxygen makes carbon dioxide + water + blank.

Accepted Answer

Sugar + oxygen makes carbon dioxide + water + energy. Respiration releases energy from sugar for cells to use.

Question 9

Look at a leaf. Tiny openings on leaves let gases move in and out. What are these openings called, and why are they important?

Accepted Answer

The tiny openings are called stomata. They are important because carbon dioxide enters the leaf and oxygen can leave through them.

Question 10

Chlorophyll is a green substance in leaves. What job does chlorophyll do during photosynthesis?

Accepted Answer

Chlorophyll captures light energy from the Sun. This light energy helps the plant make sugar during photosynthesis.

Question 11

During the day, a healthy green plant is doing photosynthesis and respiration. Which process uses carbon dioxide, and which process releases carbon dioxide?

Accepted Answer

Photosynthesis uses carbon dioxide. Respiration releases carbon dioxide when cells break down sugar for energy.

Question 12

A plant is kept in a closet for one week and gets water but no light. Predict what may happen to the plant and explain why.

Accepted Answer

The plant may become weak, pale, or stop growing well because it cannot do enough photosynthesis without light. It may use stored sugar but will not be able to make much new food.

Question 13

Match each process with its main purpose. Photosynthesis: makes sugar or releases energy. Respiration: makes sugar or releases energy.

Accepted Answer

Photosynthesis makes sugar. Respiration releases energy from sugar so cells can use it.

Question 14

The diagram shows a simple cycle between plants and animals. Plants give off oxygen. Animals give off carbon dioxide. Explain how this helps both living things.

Accepted Answer

Plants help animals by giving off oxygen that animals need for respiration. Animals help plants by giving off carbon dioxide that plants use for photosynthesis.

Question 15

Explain one way photosynthesis and respiration are connected.

Accepted Answer

Photosynthesis and respiration are connected because photosynthesis makes sugar and oxygen, and respiration uses sugar and oxygen to release energy. The products of one process can become materials for the other process.

Biology: Photosynthesis and Respiration

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