Table of Contents
Why is a variegated leaf used?
A variegated leaf is useful in conducting experiments to show that chlorophyll is needed for photosynthesis to happen. They are also popular in horticulture.
How do you destarch leaves?
Destarching a plant: Before carrying out any photosynthesis practical it is necessary to destarch the plant by placing it in the dark for at least 48 hours. During this time any starch will be removed or used.
How do you know if a plant is Photosynthesising?
Therefore, to test if a plant has been photosynthesising, you can test the leaf to see if starch is present….Investigating photosynthesis – starch and chlorophyll
- transported to the growing parts of the plant for use in respiration.
- transformed into cellulose , proteins and oils.
- turned into starch for storage.
Why are leaves destarched before an experiment?
In sunlight, Calvin cycle goes on which produces continuous starch or remains in the form of starch. And if the experiment is still continued, then the experiment will show false results. So, to get positive yield at the end of experiment leaves should be destarched.
Why do you have to boil the leaf in water the second time?
Why do you have to boil the leaf in water the second time? To soften the leaf.
What happens when a green leaf is boiled in water?
Boiling the leaf damages the membranes of the cells allowing the pigments to be leached out of the cells. After leaching, the iodine solution added will combine with any starch in the cells producing a dark purple to black pigment in the leaf.
What happens when you destarch a leaf?
Destarching occurs in a plant when a part of a plant is “deprived of starch, as by translocation”. This is done by leaving the plant(s) in a dark place for a long period of time. Due to the lack of photosynthesis in this place, stored starch is used up, thus the plant is destarched.
How do you destarch the leaves of a potted plant?
Leaves can be destarched by depriving them of light for an extended period of time, usually 24-48 hours. Potted plants are convenient to work with because they can easily be placed in a dark cupboard, or under a bell jar draped with a black cloth.
How does photosynthesis work step by step?
The two stages of photosynthesis: Photosynthesis takes place in two stages: light-dependent reactions and the Calvin cycle (light-independent reactions). Light-dependent reactions, which take place in the thylakoid membrane, use light energy to make ATP and NADPH.
Why is the leaf destarched?
A leaf is destarched so that the previously formed starch of the leaves goes down into the stem and roots of the plant, so that newly formed starch is only used used in the experiment.
Why should a plant be destarched?
All plants have starch in their green leaves. Therefore, the plant must be destarched by keeping the plant in a completely dark room for at least 3 days. During this period, the plant cannot make more starch by photosynthesis as there is no sunlight and will use up all the starch stored in its leaves.
Why do we put leaf in alcohol?
We boil the leaf in alcohol when we are testing it for starch because to remove the green pigment chlorophyll present in it. Hence to remove the green pigment present in the leaf we boil the leaf in alcohol when we are testing it for starch.