science practicles

EXPERIMENT – 9

To Prove that Light is Necessary for Photosynthesis.

Aim

:

To show experimentally that light is necessary for photosynthesis. Requirements

:

A potted plant, iodine solution, black paper strip, paper clips, water bath.

EXPERIMENT PLEASE VIEW THE ANIMATION FILE FOR THE PROCEDURE
Observation

:

1)

The region of the leaf which was exposed to sunlight turns blue in colour.

2)

The region of the leaf covered with black strip turns brownish in colour.

Inference

:

This experiment shows that sunlight is necessary for photosynthesis. Multiple Choice Questions

1)

In the experiment on photosynthesis, the leaf is boiled in alcohol kept in a water bath because ................ .
(a)

Alcohol is bad for leaf

(b)

alcohol is volatile

(c)

Alcohol catches fire on heating directly

(d)

alcohol leaves fumes

Ans.)
Alcohol catches fire on heating directly.

2)

Which of the following is not essential for photosynthesis?
(a)

Oxygen

(b)

Carbon dioxide

(c)

Light

(d)

Chlorophyll

Ans.)
Oxygen
3)

In the experiment, why is the leaf boiled in alcohol using a water bath to test the presence of starch?

(a)

Alcohol softens the leaf

(b)

Alcohol disallows iodine to enter the leaf

(c)

Alcohol allows iodine to enter the leaf

(d)

Alcohol dissolves chlorophyll

Ans.)
Alcohol dissolves chlorophyll

4)

Ankita wanted to test glucose bought by her to see whether it was adultered with starch or not. How should she test it ?
(a)

By sieving

(b)

By dissolving it in water

(c)

By iodine test

(d)

All of these

Ans.)
By iodine test
5)

For the set up of which experiment is destarching of plant done?
(a)

(b)

Photosynthesis

(c)
Ans.)

Transpiration
Respiration

(d)

Diffusion

Photosynthesis

6)

In which form is the excess of carbohydrates, the energy source, taken in food accumulated in our