Matter & Energy in Living Systems — Investigation · Life Science: Biology, Grade 10
Model photosynthesis, respiration, and how atoms cycle while energy is transferred.
Account for Carbon and Gas Exchange
Investigate
What does a change in oxygen reveal about photosynthesis and respiration?
Use three sessions: define question, boundary, model and route; collect or analyze the supplied repeated records; then graph, explain, revise and submit the notebook. Home-study activities do not certify NYSED laboratory minutes or mandated investigations.
Materials
- Supplied chamber data
- Calculator
- Graph paper
Before you begin
Use the supplied paper-and-data model. This activity requires no biological samples, cultures, personal health information, or tests on people.
Plan a fair test
Compare light conditions with equal plant material, chamber volume, temperature, duration, and starting conditions. Net oxygen change combines oxygen production and consumption. A blank chamber checks sensor/background drift.
Method
- Draw the chamber boundary and label photosynthesis and respiration transfers.
- Calculate mean oxygen change for each light condition.
- Compare with the blank chamber.
- Under the simplifying assumption of equal respiration in light and dark, estimate gross oxygen production at high light.
- Explain why a net value of zero does not mean both processes stopped.
- Propose a test of whether temperature changed between conditions.
Open the investigation data (illustrative)
Illustrative data authored for this activity, not an actual experiment or an official mandated investigation. Use them as supplied evidence, not as your own observations.
| Condition | Trial 1 net O₂ (units/hour) | Trial 2 net O₂ (units/hour) |
|---|---|---|
| Blank, no plant | 0 | 0 |
| Plant, dark | -3 | -3 |
| Plant, low light | 1 | 1 |
| Plant, high light | 5 | 5 |
Analyze and explain
- Estimate high-light gross production using the dark respiration estimate.
- Explain the carbon and energy roles of both processes.
- What happens to the estimate if respiration differs between light and dark?
- Separate collected measurements from the supplied illustrative records.
- Explain how labeled mechanisms constrain the pattern rather than only restate the graph.
- Propose a further comparison that could distinguish an alternative explanation.
What a strong explanation includes
- Distinguishes net change from each underlying rate
- Shows the blank and dark comparison
- Labels the equal-respiration assumption
- Explains matter accounting separately from energy transfer
- State units, boundary, comparable conditions and model assumptions.
- Retain a first explanation and an evidence-supported revision.
Parent / teacher guide: discuss after the investigation
The high-light net change is +5 units/hour. If respiration consumes 3 units/hour as in darkness, estimated gross production is 8 units/hour. Net zero could mean equal production and consumption. Photosynthesis transfers light energy into chemical processes; respiration transfers chemical energy into ATP and heat. If respiration changes in light, the gross estimate must be revised. A complete response also states the system boundary, units, matched conditions and limitations. Distinguish supplied illustrative outcomes from collected measurements, and explain why your revised mechanism fits the relevant evidence. Different observations should be interpreted rather than replaced to match the example.
Compare this model with the learner’s actual evidence. Different measurements can support a different conclusion; check the reasoning and limitations, not matching wording.