Lab Activity on Photosynthesis with steps presence of
Answers
1)Take a hydrilla plant and place it in a beaker filled with water.
2)Place an inverted funnel over the hydrilla plant and invert a test-tube full of water over the stem of the beaker.
3)Allow this arrangement to rest in sunlight for a few hours.
Observation: It is observed that in the presence of sunlight, bubbles emerge from the leaves of the hydrilla plant, move through the stem of the funnel and form a gap in the test tube by displacing some water.
When the gas is tested, by bringing a glowing splinter close to it, the splinter bursts into flame as oxygen is a supporter of combustion, alkaline pyrogallol solution turns brown on coming in contact with the gas, indicating that the gas is oxygen.
If sodium bicarbonate is dissolved in the water, it breaks down to form carbon dioxide, as the CO2 concentration in the water increases, rate of photosynthesis also increases as photosynthesis requires carbon dioxide, hence more oxygen is collected in the test tube and more bubbles are formed.
If blue or red light is used instead of white light, as these wavelengths of light are best absorbed by chlorophyll, more photons are available for photolysis of water, the rate of photosynthesis increases and more bubbles of oxygen are seen.
If the leaves of the plant are tested for starch, the iodine solution turns blue-black indicating that photosynthesis took place.
chlorophyll
6CO2 + 12H2O------------->C6H12O6 + 6H2O + 6O2
sunlight