7th grade · Science · Unit 4 of 16
Photosynthesis & Respiration
How cells make and use energy
What your child practices
The reactants, products and location of photosynthesis and cellular respiration, why they are complementary, and how they link plants, animals and the carbon cycle.
Alabama Course of Study content standard: 7.2 · how photosynthesis and cellular respiration cycle matter and move energy
How we explain it
Children can open this short lesson before they practice.
- Photosynthesis (in chloroplasts): carbon dioxide + water + light → glucose + oxygen.
- Cellular respiration (in mitochondria): glucose + oxygen → carbon dioxide + water + energy.
- The products of each are the reactants of the other, which cycles carbon.
Example: Which process releases oxygen: photosynthesis or respiration? Respiration uses oxygen. Photosynthesis gives it off. Answer: photosynthesis
Photosynthesis & Respiration in Alabama
In the Alabama Course of Study, this is unit 4 of 16 in 7th grade Science, after Cells, Tissues & Organs and before Cells from Cells.
Gradelings describes a child's practice on this unit as Beginning, Approaching, Meeting or Exceeding (Four practice steps). That reflects practice, not a report-card mark: the teacher decides the mark.
Sample questions
A taste of this unit. In the app, questions change every time and get easier or harder to match your child.
Question 1
What are the reactants of photosynthesis?
- glucose and oxygen
- glucose and carbon dioxide
- carbon dioxide and water
- oxygen and water
carbon dioxide and water
Hint: Plants take in carbon dioxide from the air and water from the soil.
Question 2
In 6 CO₂, how many carbon atoms are there altogether?
answer box
6
Hint: Each CO₂ has 1 carbon atom, and there are 6 of them.
Question 3
Photosynthesis or cellular respiration? Sort each statement.
Sort into: ☀️ Photosynthesis · ⚡ Cellular respiration
- 🔥Breaks down glucose
- 🐾Happens in plant and animal cells
- 💭Releases carbon dioxide
- 🌿Happens in chloroplasts
- 💨Releases oxygen
- ☀️Uses light energy
☀️ Photosynthesis: Happens in chloroplasts, Releases oxygen, Uses light energy · ⚡ Cellular respiration: Breaks down glucose, Happens in plant and animal cells, Releases carbon dioxide
Hint: Photosynthesis builds glucose using light. Cellular respiration breaks glucose down to release energy.
Question 4
A sealed jar holds a healthy plant and a small snail in the light. Why can both survive for a while?
- The plant makes no oxygen
- Neither one uses energy
- The snail makes oxygen
- The plant's oxygen supports the snail's respiration, and the snail's carbon dioxide supports the plant
The plant's oxygen supports the snail's respiration, and the snail's carbon dioxide supports the plant
Hint: Each organism provides what the other needs.
Question 5
What are the products of photosynthesis?
- carbon dioxide and glucose
- glucose and oxygen
- water and oxygen only
- carbon dioxide and water
glucose and oxygen
Hint: The plant stores energy in glucose and releases oxygen.
Question 6
Where in a cell is most of the energy released by cellular respiration?
- the nucleus
- chloroplasts
- the cell membrane
- mitochondria
mitochondria
Hint: Mitochondria are the cell's energy converters.