ICSE 2018: A potted plant with variegated leaves was taken in order to prove a factor necessary for photosynthesis.

ICSE 2018

Q. A potted plant with variegated leaves was taken in order to prove a factor necessary for photosynthesis. The potted plant was kept in the dark for 24 hours and then placed in bright sunlight for a few hours. Observe the diagram and answer the questions. [5]

 

(i) What aspect of photosynthesis is being tested in the above diagram? 

(ii) Represent the process of photosynthesis in the form of a balanced equation. 

(iii)Why was the plant kept in the dark before beginning the experiment? 

(iv)What will be the result of the starch test performed on leaf ‘A’ shown in the diagram? Given an example of a plant with variegated leaves. 

(v) Draw a neat labelled diagram of a chloroplast.

Solution:

This 5 marks question based on the process of PHOTOSYNTHESIS and was asked by ICSE board in the year 2018 in SECTION-II. 

The question tested the knowledge of students on the: 

• What is Photosynthesis?
• By products of Photosynthesis
• Starch Test on the byproducts of Photosynthesis
• Diagram of Chloroplast

Let's begin with solving the above mentioned questions:

(i) Above diagram tests that Chlorophyll is necessary for Photosynthesis.

(ii) The balanced equation for photosynthesis is:

(iii) The plant was kept in dark before beginning the experiment in order to destarch the leaves.

(iv) The effect of Starch test on Part A will be that when leaf is treated with iodine, the green portions of leaf will turn blue-black in color due to presence of starch in it while non-green parts of the leaf will not turn blue-black as it will be starch-free.

Examples of plants with variegated leaves are: Geranium, Croton, Coleus

(v) Diagram of Chloroplast: