Biology – Investigation of limiting factors | e-Consult
Investigation of limiting factors (1 questions)
Login to see all questions.
Click on a question to view the answer
Equipment Required:
- Chloroplast suspension in buffer solution
- Light source with filters of different wavelengths (e.g., red, green, blue, yellow)
- Closed system: Funnel and test tubes
- Measuring cylinder
- Thermometer
- Light meter (to ensure consistent light intensity)
- Water bath (to maintain constant temperature)
Experimental Procedure:
- Prepare a chloroplast suspension as described in the previous question.
- Set up the apparatus as described in the previous question, ensuring the light source is positioned at a fixed distance.
- Cover the funnel with a filter of a specific wavelength (e.g., red). Ensure the light intensity is consistent across all wavelengths using the light meter.
- Allow the system to equilibrate for a few minutes.
- Measure the volume of oxygen produced in the test tube over a set period (e.g., 5 minutes). Repeat this measurement multiple times (e.g., 3-5 times) for each wavelength.
- Repeat the experiment for each of the different wavelengths.
Data Analysis:
The rate of photosynthesis can be calculated by dividing the volume of oxygen produced by the time interval (e.g., mL O2/min). The results can be plotted as a bar graph, with the wavelength of light on the x-axis and the rate of photosynthesis on the y-axis. This will allow for a visual comparison of the effect of different wavelengths on the rate of photosynthesis.
Potential Sources of Error and Minimisation:**
- Temperature fluctuations: Temperature can affect the rate of photosynthesis. Minimise: Use a water bath to maintain a constant temperature throughout the experiment.
- Inconsistent light intensity: Variations in light intensity can affect the rate of photosynthesis. Minimise: Use a light meter to ensure that the light intensity is consistent across all wavelengths.
- Variation in chloroplast concentration: The concentration of chloroplasts in the suspension may vary. Minimise: Use a standardized procedure for preparing the chloroplast suspension.
- Oxygen leakage: Oxygen may leak out of the closed system. Minimise: Ensure that the funnel and test tube are tightly sealed.
- Diffusion limitations: Oxygen diffusion within the suspension may be slow. Minimise: Ensure the chloroplast suspension is well mixed.