Question

While preparing for experiment the study of light is necessary for photosynthesis, one step is invalid. Which step is it?

(i) Plant/leaf should be destarched for 10-12 hours (overnight preferably).

(ii) Black strips of paper or light screen should be used for covering the leaf/leaves.

(iii) Plant without leaves should be used.

(iv) Potted plant should be kept under sunlight for 2-4 hours at least.

• A. (i)
• B. (ii)
• C. (iii)
• D. (iv)

Answer 1

The correct option is C

(iii)

The correct option is (C)

Explanation for the correct option:

1. Photosynthesis is the process of forming food in plants. It occurs with the help of a green photosynthetic pigment called chlorophyll.
2. Photosynthetic pigments are present in the leaves of a plant.
3. Therefore it is essential to have a plant with leaves to study photosynthesis.

Explanation for incorrect options:

Option (A):

1. Before conducting the experiment for starch formation the plant is placed in the dark to lose its stored starch from the leaves.
2. Destarching the leaves enabled us to validate the amount of starch formed during the experiment.

Option (B):

1. Photosynthesis occurs only in presence of light.
2. Thus, black strips help to study the effect of light on photosynthesis.

Option (D):

1. Sunlight is used for the process of photosynthesis to split the water molecule into hydrogen and oxygen.
2. This is why the potted plant is kept under the sun.

Final answer: Leaves are the photosynthetic organs present in plants.