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9th grade · Science · Unit 3 of 28

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.

New York State Learning Standards learning standard: HS-LS1-5; HS-LS1-7; HS-LS2-3; HS-LS2-5 · photosynthesis and cellular respiration, and how they cycle carbon and energy through ecosystems and the air

How we explain it

Children can open this short lesson before they practice.

  1. Photosynthesis (in chloroplasts): carbon dioxide + water + light → glucose + oxygen.
  2. Cellular respiration (in mitochondria): glucose + oxygen → carbon dioxide + water + energy.
  3. 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 New York

In the New York State Learning Standards, this is unit 3 of 28 in 9th grade Science, after Reproduction and before Human Reproductive System.

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.

Source: New York State Education Department (NYSED)

Sample questions

A taste of this unit. In the app, questions change every time and get easier or harder to match your child.

  1. Question 1

    Photosynthesis or cellular respiration? Sort each statement.

    Sort into: ☀️ Photosynthesis · ⚡ Cellular respiration

    • 🌿Happens in chloroplasts
    • 🔥Breaks down glucose
    • 💨Releases oxygen
    • 🔋Happens in mitochondria
    • ☀️Uses light energy
    • 💭Releases carbon dioxide

  2. Question 2

    Large forests are called carbon sinks because they…

    • take in more carbon dioxide than they release over time
    • release more carbon than they take in
    • stop the water cycle
    • produce no oxygen

  3. Question 3

    A sealed jar holds a healthy plant and a small snail in the light. Why can both survive for a while?

    • The plant's oxygen supports the snail's respiration, and the snail's carbon dioxide supports the plant
    • The plant makes no oxygen
    • The snail makes oxygen
    • Neither one uses energy

  4. Question 4

    What are the reactants of photosynthesis?

    • carbon dioxide and water
    • glucose and oxygen
    • oxygen and water
    • glucose and carbon dioxide

  5. Question 5

    Where in a cell is most of the energy released by cellular respiration?

    • the cell membrane
    • chloroplasts
    • the nucleus
    • mitochondria

  6. Question 6

    What are the products of photosynthesis?

    • glucose and oxygen
    • carbon dioxide and water
    • carbon dioxide and glucose
    • water and oxygen only

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