Worksheet

How photosynthesis and respiration feed each other

Grade 9 Science Worksheet - Challenge Me

NameDate

Circle the best answer.

  2. Bo uses the same graph. What is the leaf's net CO₂ change at light 40?

    • 3 mL taken in per hour
    • 5 mL released per hour
    • 8 mL taken in per hour
    • 13 mL taken in per hour

  3. Esme reads the same graph. Which statement does it support?

    Use the picture in question 1.

    • Above light 20 respiration stops, so photosynthesis takes over
    • Below light 20 the leaf gives off more CO₂ than it takes in
    • The two lines are unrelated, so where they cross means nothing
    • At light 0 the leaf takes in CO₂ because photosynthesis runs in the dark

  4. Read this first

    Use the table

    Card (real data, from OpenStax Biology 2e). Energy for the producers in a spring ecosystem, in kcal per square meter per year.

    energy measurekcal per square meter per year
    captured by the producers20,810
    used in the producers' own respiration or lost as heat13,187

  5. Jun reads real data from a spring ecosystem. About what share of the energy the producers captured went to their own respiration or heat?

    • About 0 percent, since producers make sugar and do not use it
    • About 13 percent
    • About 63 percent
    • About 37 percent

  6. Kira's class reads about two bottles in bright light (model data). Why did bottle B end with more CO₂ than bottle A?

    • The yeast did photosynthesis and made extra CO₂
    • Yeast cells released CO₂, which offset some of the plant's uptake
    • The plant stopped photosynthesizing because the yeast shaded it
    • The plant and the yeast did not affect each other, so chance made the gap

  7. Luz reads the card. How many O₂ molecules escaped from the model leaf to the air?

    • 324 molecules
    • 396 molecules
    • 36 molecules
    • 360 molecules

  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. Notebook, 3 lines. Line 1: Photosynthesis makes glucose and oxygen. Line 2: Cellular respiration uses glucose and oxygen and releases carbon dioxide and water. Line 3: So the energy that respiration releases returns to the leaf as light and powers photosynthesis again.

  9. Milo reads a notebook entry about the loop. Which line has a flaw?

    • Line 2: plants do not carry out cellular respiration in their cells
    • No line: the energy goes round like the matter does
    • Line 3: energy leaves as heat, so new light must keep coming in
    • Line 1: photosynthesis uses glucose and oxygen

  10. 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. Notebook, 3 lines. Line 1: In bright light a leaf takes in more CO₂ than it releases. Line 2: So respiration must switch off whenever light shines on the leaf. Line 3: In the dark, photosynthesis stops and respiration keeps releasing CO₂.

  11. Noah reads a notebook entry about light and dark. Which line has a flaw?

    • Line 2: mitochondria keep respiring in light while photosynthesis runs faster
    • Line 1: a leaf in light takes in oxygen, not CO₂
    • No line: respiration is a night process
    • Line 3: photosynthesis keeps running in the dark

  12. 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. Notebook, 3 lines. Line 1: The carbon atoms in glucose came from CO₂ taken in by the leaf. Line 2: The oxygen gas the leaf releases is the oxygen of that CO₂, set free when the carbon joins glucose. Line 3: In respiration, the carbon atoms of glucose leave the leaf as CO₂.

  13. Pia reads a notebook entry that traces carbon and oxygen. Which line has a flaw?

    • Line 1: the carbon in glucose comes from soil minerals
    • No line: the three lines match the loop
    • Line 3: respiration keeps the carbon of glucose inside the leaf
    • Line 2: the released oxygen comes from splitting water, not from CO₂

  14. 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.

  15. Ren's friend says the loop is perfect: energy goes around it forever, just like the carbon. Which reply is best?

    • Disagree: matter cycles, but energy enters as light and some leaves as heat
    • Agree: heat from respiration is turned back into light and reused
    • Disagree: neither matter nor energy passes between the two processes
    • Agree: the energy released in respiration powers the next round of photosynthesis

  16. Tala's friend says plants do only photosynthesis, because breaking glucose down is what animals do. Which reply is best?

    • Agree: plant cells have no mitochondria, so they cannot break glucose down
    • Disagree: plants respire in their chloroplasts, which do both jobs
    • Disagree: plant mitochondria also break glucose down, using some of the leaf's oxygen
    • Disagree: plants respire, but after dark once photosynthesis stops
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How photosynthesis and respiration feed each other

Answer Key - Grade 9 Science Worksheet - Challenge Me

Circle the best answer.

  2. Bo uses the same graph. What is the leaf's net CO₂ change at light 40?

    • 3 mL taken in per hour
    • 5 mL released per hour
    • 8 mL taken in per hour
    • 13 mL taken in per hour

  3. Esme reads the same graph. Which statement does it support?

    Use the picture in question 1.

    • Above light 20 respiration stops, so photosynthesis takes over
    • Below light 20 the leaf gives off more CO₂ than it takes in
    • The two lines are unrelated, so where they cross means nothing
    • At light 0 the leaf takes in CO₂ because photosynthesis runs in the dark

  4. Read this first

    Use the table

    Card (real data, from OpenStax Biology 2e). Energy for the producers in a spring ecosystem, in kcal per square meter per year.

    energy measurekcal per square meter per year
    captured by the producers20,810
    used in the producers' own respiration or lost as heat13,187

  5. Jun reads real data from a spring ecosystem. About what share of the energy the producers captured went to their own respiration or heat?

    • About 0 percent, since producers make sugar and do not use it
    • About 13 percent
    • About 63 percent
    • About 37 percent

  6. Kira's class reads about two bottles in bright light (model data). Why did bottle B end with more CO₂ than bottle A?

    • The yeast did photosynthesis and made extra CO₂
    • Yeast cells released CO₂, which offset some of the plant's uptake
    • The plant stopped photosynthesizing because the yeast shaded it
    • The plant and the yeast did not affect each other, so chance made the gap

  7. Luz reads the card. How many O₂ molecules escaped from the model leaf to the air?

    • 324 molecules
    • 396 molecules
    • 36 molecules
    • 360 molecules

  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. Notebook, 3 lines. Line 1: Photosynthesis makes glucose and oxygen. Line 2: Cellular respiration uses glucose and oxygen and releases carbon dioxide and water. Line 3: So the energy that respiration releases returns to the leaf as light and powers photosynthesis again.

  9. Milo reads a notebook entry about the loop. Which line has a flaw?

    • Line 2: plants do not carry out cellular respiration in their cells
    • No line: the energy goes round like the matter does
    • Line 3: energy leaves as heat, so new light must keep coming in
    • Line 1: photosynthesis uses glucose and oxygen

  10. 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. Notebook, 3 lines. Line 1: In bright light a leaf takes in more CO₂ than it releases. Line 2: So respiration must switch off whenever light shines on the leaf. Line 3: In the dark, photosynthesis stops and respiration keeps releasing CO₂.

  11. Noah reads a notebook entry about light and dark. Which line has a flaw?

    • Line 2: mitochondria keep respiring in light while photosynthesis runs faster
    • Line 1: a leaf in light takes in oxygen, not CO₂
    • No line: respiration is a night process
    • Line 3: photosynthesis keeps running in the dark

  12. 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. Notebook, 3 lines. Line 1: The carbon atoms in glucose came from CO₂ taken in by the leaf. Line 2: The oxygen gas the leaf releases is the oxygen of that CO₂, set free when the carbon joins glucose. Line 3: In respiration, the carbon atoms of glucose leave the leaf as CO₂.

  13. Pia reads a notebook entry that traces carbon and oxygen. Which line has a flaw?

    • Line 1: the carbon in glucose comes from soil minerals
    • No line: the three lines match the loop
    • Line 3: respiration keeps the carbon of glucose inside the leaf
    • Line 2: the released oxygen comes from splitting water, not from CO₂

  14. 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.

  15. Ren's friend says the loop is perfect: energy goes around it forever, just like the carbon. Which reply is best?

    • Disagree: matter cycles, but energy enters as light and some leaves as heat
    • Agree: heat from respiration is turned back into light and reused
    • Disagree: neither matter nor energy passes between the two processes
    • Agree: the energy released in respiration powers the next round of photosynthesis

  16. Tala's friend says plants do only photosynthesis, because breaking glucose down is what animals do. Which reply is best?

    • Agree: plant cells have no mitochondria, so they cannot break glucose down
    • Disagree: plants respire in their chloroplasts, which do both jobs
    • Disagree: plant mitochondria also break glucose down, using some of the leaf's oxygen
    • Disagree: plants respire, but after dark once photosynthesis stops