how sunlight ,CO2 and chlorophyll are essential for photosynthesis diagram
Answers
1. Chlorophyll is necessary for photosynthesis
Process
Take a potted plant with variegated (green and white) leaves.
Destarch the plant by keeping it in complete darkness for about 48 hours.
Expose the plant to the sunlight for a few days.
Test one of the leaves for starch with iodine solution.
Observations
- Areas with previously green patches test positive (turn blue black).
- Areas with previously pale yellow patches test negative (remain brown).
Conclusion
- Photosynthesis takes place only in green patches because of the presence of chlorophyll.
- The pale yellow patches do not perform photosynthesis because of the absence of chlorophyll.((ref 1st IMG))
2. Light is essential for photosynthesis
Process
Take a potted plant.
Destarch the plant by keeping it in complete darkness for about 48 hours.
Test one of it leaves for starch, to check that is does not contain any.
Fix a leaf of this plant in between two strips of a thick paper on leaf.
Place the plant in light for a few days.
Remove the cover from the leaf and test it for starch.
Observations
Positive starch test will be obtained only in the portion of the leaf exposed to light and negative test in parts with paper strip.
Conclusion
Light is necessary for photosynthesis.
((ref IMG 2,3))
3. Carbon dioxide is essential for photosynthesis
Process
Take two destarched potted plants.
Cover both the plants with bell jars and label them as A and B.
Inside Set-up A, keep NaHCO3 (sodium bicarbonate). It produces CO2.
Inside Set-up B, keep NaOH (Sodium hydroxide). It absorbs CO2.
Keep both the set-ups in the sunlight at least for 6 hours.
Perform the starch test on both of the plants.
Observations
Leaf from the plant in which NaHCO3 has been placed gives positive test.
Leaf from the plant in which NaOH has been kept give negative test.
Conclusion
Plant in Set up A gets CO2 whereas plant in Set-up B does not get CO2.
It means CO2 is must for photosynthesis.