The Practical Techniques used to Investigate Photosynthesis

The Practical Techniques used to Investigate Photosynthesis

  • Photosynthesis is the process by which green plants use sunlight to synthesise glucose from carbon dioxide and water. It can be represented as: 6CO2 + 6H2O —> C6H12O6 + 6O2.

  • It’s essential to understand how different factors can influence this process. There are several practical techniques used to investigate photosynthesis. These include:

  • Light intensity experiment: This involves changing the distance of a light source from a plant (usually an aquatic plant like Elodea). As the light gets closer, the rate of photosynthesis should increase - demonstrated by a faster rate of oxygen bubble production.

  • Carbon dioxide concentration: Modifying the amount of carbon dioxide available to the plant can also regulate the rate of photosynthesis. This can be achieved by dissolving different amounts of a CO2 source, like sodium hydrogen carbonate, in the water around the plant.

  • Temperature: By altering the temperature of the environment, one can observe the effect on photosynthesis rate. You have to be careful with this one - at extremely high temperatures, the enzymes responsible for photosynthesis can denature.

  • Measuring photosynthesis: The rate of photosynthesis is commonly measured by the rate of oxygen production, which can be observed with the use of an inverted measuring cylinder or burette to capture and measure the volume of O2 produced.

  • Using a colourimeter: A colourimeter measures the absorbance of particular wavelengths of light. It can be used to determine the concentration of chlorophyll in a sample, indicating the plant’s potential for photosynthesis.

  • Dealing with experimental variables: During all these experiments, it’s vital to keep other factors constant - this ensures the changes observed are only due to the factor being investigated.

  • Analysing results: Make sure to record results accurately and present in appropriate formats such as tables and graphs. Also, discuss the reliability, precision, and validity of your results, using different statistical tests where relevant.

  • Safety: It’s essential to consider safety throughout the experiments, avoiding direct contact with heat or chemicals; wearing protective gear such as goggles and gloves when required.

To understand photosynthesis more effectively, these practical techniques allow us to visualise the conditions necessary for this crucial biological process. By manipulating a variable, we can determine its effect on the rate of photosynthesis, greatly contributing to our understanding of plant biology.