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?

   • Carbon dioxide and water
   • Nothing, since the processes share no substances
   • Glucose and oxygen
   • 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
   • Makes them again from carbon dioxide and water
   • Turns them into light energy for the leaf
   • Uses them as its starting substances
5. 3.

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

   • Zero, since the boxes pass no substances
   • One, from photosynthesis to respiration
   • Two, one pointing each way
   • Two, both from respiration to photosynthesis
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 chloroplast, and the cell has no organelle B
   • A is a chloroplast and B is a mitochondrion
   • A is a mitochondrion and B is a chloroplast
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 leaf's own mitochondria, for respiration
   • The mitochondria, but they work after dark and pause by day
   • The chloroplast, to make more glucose
   • No part, since plant cells take in no oxygen
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 uses light to make its own food
    • An organism that does photosynthesis but not respiration
    • An organism that gets energy from chemicals, not light
11. 8.

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

    • An organism that has no link to photosynthesis
    • An organism that makes its own sugar from light
    • An organism that relies on sugars made by others
    • An organism that runs on light and needs no sugar
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 one reaction releases that another can use
    • A leftover that no cell can use
    • A substance the cell absorbs straight from light

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