Why do you soak the leaf in a boiling water after heating it in alcohol?
Complete answer: We boil the leaf in alcohol when we are checking it for starch to eradicate chlorophyll, which is the green pigment present in leaves. During the starch test, we observe the colour change of leaf from brown to blue when iodine is put on the leaf as iodine reacts with the starch present in the leaf.
Why is it necessary to boil the leaf in water?
The purpose of boiling leaf in the water is to break down the cell membrane, soften the cuticle layer and cells walls.
What happens when a 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 put a leaf in warm water?
Explanation: Push the leaf into some warm water. Watch carefully to see where air bubbles appear on the leaf surface. Leaves have tiny holes in their lower surfaces, called stomata, which allow carbon dioxide to get into the leaf from the air.
What is the purpose of softening the leaf by boiling in water class 7?
Answer: (a) The leaf is boiled for a short time to remove the chlorophyll.
How does boiling leaves affect photosynthesis?
When chloroplasts are boiled, the enzymes that are needed for photosynthesis denature. With the denaturation of the enzymes in the chloroplasts, DPIP is unable to be reduced to DPIPH. Without this reduction reaction, the light reactions of photosynthesis cannot occur.
Why is it necessary to boil the ethanol tube in the water bath?
the tube is immersed in water bath as it contains alcohol and alcohol is easily flammable. by heating the alcohol directly ,it will catch fire. it is immersed in water bath so that alcohol doesn’t catch fire.
Why do leaves become Colourless after boiling in spirit?
wHat do we conclude? When we boil the leaves in spirit they become colourless because chlorophyll pigments leach out. Leaves contain starch which gives blue-black colour with iodine solution. Starch is synthesised in the green leaves in the presence of sunlight by the process of photosynthesis.