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?

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

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?

   • Ignores them and runs on its own supply
   • Uses them as its starting substances
   • Turns them into light energy for the leaf
   • 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, one pointing each way
   • Two, both from respiration to photosynthesis
   • One, from photosynthesis to respiration
   • Zero, since the boxes pass no substances
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 B, from the muscle of a person
   • Cell C, from the yeast in bread dough
   • No cell, since a cell makes sugar or uses it, not both
   • Cell A, from the green leaf

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?

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

    Milo reads a word list. Which meaning matches the term photoautotroph?

    • An organism that must take in sugars made by others
    • An organism that gets energy from chemicals, not light
    • An organism that uses light to make its own food
    • An organism that does photosynthesis but not respiration
11. 8.

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

    • An organism that has no link to photosynthesis
    • An organism that runs on light and needs no sugar
    • An organism that makes its own sugar from light
    • An organism that relies on sugars made by others
12. 9.

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

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

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: energy moved to ATP and heat.

14. 10.

    Zee reads the whole loop. Which statement about energy in the loop is right?

    • Energy is made fresh by the leaf cell
    • Energy enters as heat and leaves as light
    • Energy enters as light and some leaves as heat
    • Energy goes round and round like the matter does