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9th grade How photosynthesis and respiration feed each other worksheet

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How photosynthesis and respiration feed each other

Grade 9 Science Worksheet - Building Confidence

NameDate

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. 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. 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. 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. 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. 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. 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. 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. 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. 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. 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
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9th grade How photosynthesis and respiration feed each other worksheet – printable
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About this worksheet

How photosynthesis and respiration feed each other. Every version has 10 questions, and the answer key prints on the second page.

What your child will learn

  • I can read a loop diagram and say that glucose and oxygen go from photosynthesis to cellular respiration, and carbon dioxide and water go back, so the products of each process are the starting substances of the other.
  • I can say that matter cycles through the loop but energy flows through it: light comes in, some leaves as heat, and heat is not collected and sent back as light.
  • I can say plants do both processes: a leaf cell holds chloroplasts and mitochondria, and the mitochondria use some of the oxygen the chloroplasts make (about 10 percent).
  • I can say respiration runs in light and in dark, and photosynthesis is the process that needs light.
  • I can read a gas card for a leaf in light and in dark and work out that a net uptake in light is photosynthesis minus respiration (and that the dark row shows respiration alone).
  • I can read a graph with a photosynthesis line and a respiration line, find where they are equal, and say which side releases more CO₂ than it takes in (model data; the term for that point is not used, see section 11).

Standard: HS-LS1-5, HS-LS1-7

Words to know

reactant, product: A starting substance of a reaction; a substance the reaction makes

photosynthesis: Using light to build glucose from carbon dioxide and water, releasing oxygen

cellular respiration: Breaking glucose down with oxygen to make ATP, releasing carbon dioxide and water

chloroplast: The plant cell part that carries out photosynthesis

mitochondrion (plural: mitochondria): The cell part where most of cellular respiration takes place

photoautotroph: An organism that uses light to make its own food

heterotroph: An organism that relies on sugars made by other organisms

byproduct: A substance one reaction releases that another reaction can use

Common mistakes

Your child thought plants do photosynthesis but not cellular respiration. Plant cells have chloroplasts and mitochondria, so they make glucose and also break it down. Ask your child which two organelles a leaf cell holds.

Your child thought energy goes round the loop the way matter does. Carbon, oxygen and water cycle, but energy enters as light and some leaves as heat. Ask your child where the energy comes in and where some of it leaves.

Your child thought cellular respiration happens only at night, or stops when the light is on. Respiration runs in light and in dark; photosynthesis is the one that needs light. Ask your child which of the two needs light.

Questions parents ask

What is the most common mistake with how photosynthesis and respiration feed each other?

Your child thought plants do photosynthesis but not cellular respiration. Plant cells have chloroplasts and mitochondria, so they make glucose and also break it down. Ask your child which two organelles a leaf cell holds.

Are these 9th grade science worksheets free to print?

Yes. All 6 printable versions at each level are free to print, with the answer key, and no account is needed.

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