How photosynthesis and respiration feed each other

Grade 9 Science Worksheet - Building Confidence

Circle the best answer.

1. Read this first

   Use this

   Flow diagram drawn as a loop (model, not to scale), inside a leaf cell. Two process boxes: photosynthesis, in the chloroplast, on the left; cellular respiration, in the mitochondrion, on the right. An arrow from photosynthesis to cellular respiration carries: glucose; oxygen. The arrow from cellular respiration back to photosynthesis is blank. A wavy arrow points into photosynthesis: light energy. A wavy arrow points out of cellular respiration: energy moved to ATP and heat.

2. 1.

   Ari reads a loop diagram of a leaf cell. The arrow from cellular respiration back to photosynthesis is blank. Which substances belong on it?

   • Light energy and heat
   • Glucose and oxygen
   • Nothing, since the processes share no substances
   • Carbon dioxide and water

3. Use this

   Flow diagram drawn as a loop (model, not to scale), inside a leaf cell. Two process boxes: photosynthesis, in the chloroplast, on the left; cellular respiration, in the mitochondrion, on the right. An arrow from photosynthesis to cellular respiration carries: glucose; oxygen. An arrow from cellular respiration back to photosynthesis carries: carbon dioxide; water. A wavy arrow points into photosynthesis: light energy. A wavy arrow points out of cellular respiration: energy moved to ATP and heat.

4. 2.

   Bo reads that photosynthesis hands glucose and oxygen to cellular respiration. What does cellular respiration do with them?

   • Turns them into light energy for the leaf
   • Uses them as its starting substances
   • Ignores them and runs on its own supply
   • Makes them again from carbon dioxide and water
5. 3.

   Esme counts the arrows that carry matter between the two boxes. How many are there, and which way do they point?

   • Two, both from respiration to photosynthesis
   • One, from photosynthesis to respiration
   • Zero, since the boxes pass no substances
   • Two, one pointing each way
6. 4.

   Jun reads a leaf cell with two organelles, A and B. Which pair of names fits A and B?

   • A is the nucleus and B is the cell wall
   • A is a mitochondrion and B is a chloroplast
   • A is a chloroplast and B is a mitochondrion
   • A is a chloroplast, and the cell has no organelle B
7. 5.

   Four cells are drawn (not to scale). Kira compares four cells. Which one has both chloroplasts and mitochondria?

   • Cell A, from the green leaf
   • Cell C, from the yeast in bread dough
   • No cell, since a cell makes sugar or uses it, not both
   • Cell B, from the muscle of a person

8. Use this

   Flow diagram drawn as a loop (model, not to scale), inside a leaf cell. Two process boxes: photosynthesis, in the chloroplast, on the left; cellular respiration, in the mitochondrion, on the right. An arrow from photosynthesis to cellular respiration carries: glucose; oxygen. An arrow from cellular respiration back to photosynthesis carries: carbon dioxide; water. A wavy arrow points into photosynthesis: light energy. A wavy arrow points out of cellular respiration: energy moved to ATP and heat.

9. 6.

   Luz sees a chloroplast release oxygen in a leaf cell. Which part of the same leaf can use some of that oxygen?

   • The chloroplast, to make more glucose
   • The leaf's own mitochondria, for respiration
   • The mitochondria, but they work after dark and pause by day
   • No part, since plant cells take in no oxygen
10. 7.

    Noah reads a word list. Which meaning matches the term heterotroph?

    • An organism that makes its own sugar from light
    • An organism that relies on sugars made by others
    • An organism that has no link to photosynthesis
    • An organism that runs on light and needs no sugar
11. 8.

    Pia reads that, in the loop, oxygen from photosynthesis is called a byproduct. What does that word mean here?

    • A substance one reaction releases that another can use
    • A substance the cell absorbs straight from light
    • A leftover that no cell can use
    • A substance made by animals, not by plants
12. 9.

    “model, not to scale” Ren reads the wavy arrow that points into photosynthesis. Its label is blank. What does it carry?

    • Energy taken from the soil
    • Light energy
    • Chemical energy from glucose
    • Heat energy from respiration

13. Use this

    Flow diagram drawn as a loop (model, not to scale), inside a leaf cell. Two process boxes: photosynthesis, in the chloroplast, on the left; cellular respiration, in the mitochondrion, on the right. An arrow from photosynthesis to cellular respiration carries: glucose; oxygen. An arrow from cellular respiration back to photosynthesis carries: carbon dioxide; water. A wavy arrow points into photosynthesis: light energy. A wavy arrow points out of cellular respiration. Its label is blank.

14. 10.

    Tala reads the wavy arrow that points out of cellular respiration. Its label is blank. What does it carry?

    • Energy released at night and paused by day
    • Light energy sent back to photosynthesis
    • New energy created by the cell
    • Energy moved to ATP, plus heat