How photosynthesis and respiration feed each other
Grade 9 Science Worksheet - Challenge Me
Circle the best answer.
Bo uses the same graph. What is the leaf's net CO₂ change at light 40?
- 5 mL released per hour
- 3 mL taken in per hour
- 8 mL taken in per hour
- 13 mL taken in per hour
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
- 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
- Below light 20 the leaf gives off more CO₂ than it takes in
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 measure kcal per square meter per year captured by the producers 20,810 used in the producers' own respiration or lost as heat 13,187 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 13 percent
- About 0 percent, since producers make sugar and do not use it
- About 37 percent
- About 63 percent
Luz reads the card. How many O₂ molecules escaped from the model leaf to the air?
- 324 molecules
- 396 molecules
- 36 molecules
- 360 molecules
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.
Milo reads a notebook entry about the loop. Which line has a flaw?
- Line 3: energy leaves as heat, so new light must keep coming in
- No line: the energy goes round like the matter does
- Line 2: plants do not carry out cellular respiration in their cells
- Line 1: photosynthesis uses glucose and oxygen
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.
Noah reads a notebook entry about light and dark. Which line has a flaw?
- Line 3: photosynthesis keeps running in the dark
- No line: respiration is a night process
- Line 2: mitochondria keep respiring in light while photosynthesis runs faster
- Line 1: a leaf in light takes in oxygen, not CO₂
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.
Pia reads a notebook entry that traces carbon and oxygen. Which line has a flaw?
- Line 2: the released oxygen comes from splitting water, not from CO₂
- No line: the three lines match the loop
- Line 1: the carbon in glucose comes from soil minerals
- Line 3: respiration keeps the carbon of glucose inside the leaf
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.
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: the energy released in respiration powers the next round of photosynthesis
- Agree: heat from respiration is turned back into light and reused
- Disagree: neither matter nor energy passes between the two processes
Tala's friend says plants do only photosynthesis, because breaking glucose down is what animals do. Which reply is best?
- Disagree: plants respire, but after dark once photosynthesis stops
- Agree: plant cells have no mitochondria, so they cannot break glucose down
- Disagree: plant mitochondria also break glucose down, using some of the leaf's oxygen
- Disagree: plants respire in their chloroplasts, which do both jobs
Zee's friend says the oxygen a leaf releases is the oxygen of the CO₂ it took in. Which reply is best?
- Disagree: the O₂ comes from glucose that the mitochondria break down
- Agree: the leaf removes the carbon from CO₂ and releases the oxygen as O₂
- Disagree: the O₂ comes from splitting water, and the CO₂ carbon goes into glucose
- Disagree: the light energy turns directly into O₂ gas