Science: Photosynthesis and Cellular Respiration
How cells make and use energy
Science: Photosynthesis and Cellular Respiration
How cells make and use energy
Science - Grade 6-8
- 1
What is the main purpose of photosynthesis in plants?
Think about how plants make their own food.
The main purpose of photosynthesis is to use light energy to make glucose, which stores chemical energy for the plant. - 2
What is the main purpose of cellular respiration in living cells?
The main purpose of cellular respiration is to break down glucose and release energy that cells can use. - 3
List the reactants needed for photosynthesis.
Reactants are the starting materials.
The reactants for photosynthesis are carbon dioxide, water, and light energy. - 4
List the products made by photosynthesis.
The products of photosynthesis are glucose and oxygen. - 5
List the reactants needed for cellular respiration.
Cells use food and a gas from the air.
The reactants for cellular respiration are glucose and oxygen. - 6
List the products made by cellular respiration.
The products of cellular respiration are carbon dioxide, water, and usable energy for the cell. - 7
In which organelle does photosynthesis take place?
This organelle contains chlorophyll.
Photosynthesis takes place in the chloroplast. - 8
In which organelle does most cellular respiration take place?
Most cellular respiration takes place in the mitochondria. - 9
Explain how photosynthesis and cellular respiration are related.
Compare the inputs and outputs of both processes.
Photosynthesis and cellular respiration are related because the products of one process are the reactants of the other. Photosynthesis makes glucose and oxygen, which cellular respiration uses, and cellular respiration makes carbon dioxide and water, which photosynthesis uses. - 10
A plant is placed in sunlight and given water and carbon dioxide. What two main substances will it produce during photosynthesis?
The plant will produce glucose and oxygen during photosynthesis. - 11
A muscle cell uses glucose and oxygen. What process is it carrying out, and what does it release?
This process happens in animal cells as well as plant cells.
The muscle cell is carrying out cellular respiration, and it releases carbon dioxide, water, and energy. - 12
Why do animals depend on photosynthesis even though animals do not perform photosynthesis?
Animals depend on photosynthesis because it produces oxygen for breathing and makes glucose that enters food chains. - 13
True or false: Only plants carry out cellular respiration. Explain your answer.
Think about whether animal cells need energy.
This statement is false. Plants, animals, and many other organisms carry out cellular respiration to release energy from glucose. - 14
Describe what happens to energy during photosynthesis and during cellular respiration.
During photosynthesis, light energy is captured and stored in glucose. During cellular respiration, the chemical energy in glucose is released for the cell to use. - 15
Complete the comparison: Photosynthesis mostly happens in plant cells and requires light, while cellular respiration happens in both plant and animal cells and does not require light directly. Explain why both processes are important.
One process stores energy, and the other releases it.
Both processes are important because photosynthesis stores energy by making glucose, and cellular respiration releases that stored energy so cells can do their work.