Plants make their own food – absorbing and converting sunlight energy into chemical energy stored in carbohydrates such as glucose and other biomolecules. Photosynthesis is vital for the life of plants and for all animals on the planet.
Explore the requirements for photosynthesis.
Identifying the conditions needed for photosynthesis
Test leaves for starch. Use leaves that have been exposed to different amounts of light or carbon dioxide, or that do not contain chlorophyll in every cell.
Testing leaves for starch: the technique
This basic laboratory technique allows you to identify the presence of starch in a leaf with a solution of iodine in potassium iodide.
Investigating factors affecting the rate of photosynthesis
A simple protocol for measuring the rate of photosynthesis in pond weed.
Investigating the light dependent reaction in photosynthesis
Use DCPIP as an electron acceptor for the reducing agents produced by chloroplasts in the light-dependent reaction of photosynthesis. Rate of decolourisation of DCPIP measures activity of chloroplasts.
Investigating photosynthesis using immobilised algae
Immobilise a culture of an alga such as Scenedesmus in alginate beads and measure the rate of photosynthesis by monitoring their effect on hydrogencarbonate indicator.