I'm working on a lab to show that light reactions must occur prior to dark reactions in photosynthesis.

so far, i thought of the experiment involving two plants, one exposed to sunlight, the other is kept in a box. both receive the same amount of water soil, etc and both are the same type of plant. would this actually prove that light reactions occur first though?
i'm kinda at a loss for what to do.

I don't know how you will measure these reactions, but possibly you might show what needs to occur first by using an "ABBA" arrangement with one plant and a "BAAB" arrangement with the other.

A = sunlight
B = no sunlight

However, one plant under each condition is not a large enough sample for statistical analysis.

I hope this helps. Thanks for asking.

To design an experiment that can demonstrate that light reactions occur before dark reactions in photosynthesis, you can modify your current setup to provide more evidence. Here's an experimental design which can help you come to a conclusion:

1. Plant Setup:
- Prepare two identical plants of the same species, preferably with similar sizes.
- Make sure both plants have ample sunlight exposure for some time before the experiment to establish a similar baseline.
- Keep one plant exposed to sunlight throughout the experiment (Plant A), and the other plant should be kept in complete darkness (Plant B).

2. Initial Measurements:
- Measure and record the initial parameters such as plant height, leaf number, leaf color, and overall plant health for both plants.
- These measurements will serve as your baseline data to compare with the post-experiment results.

3. Experimental Conditions:
- Continue providing both plants with equal amounts of water, nutrients, and maintaining similar environmental conditions (temperature, humidity, etc.) during the experiment.

4. Observation Period:
- Observe both plants daily and record any changes in their physical appearance, growth rate, and overall health.
- Pay attention to any visible differences that may occur between the two plants.

5. Analyzing the Results:
- After a certain period (e.g., a few weeks), compare the growth and overall health of both plants.
- If Plant A, the one exposed to sunlight, shows more vigorous and healthy growth, while Plant B shows stunted growth or signs of poor health, it suggests that light reactions are essential for optimal plant growth.
- This outcome supports the concept that light reactions must occur before dark reactions in photosynthesis.

Remember, this experiment won't directly measure the occurrence of light reactions before dark reactions, but it will offer evidence to support that hypothesis. Further experiments involving the measurement of specific biochemical markers (such as ATP and NADPH) could provide more direct evidence for the order of reactions in photosynthesis.