Question

Unicellular algae X and Y of the same species were taken, experimentally chloroplasts were removed from cell X. After some time, they both were kept in bright sunlight for a few hours and then the iodine test was performed on them. What will be the result?

• A. Both X and Y will turn blue-black
• B. Cell X will turn blue-black
• C. Cell Y will turn blue-black
• D. Both X and Y will remain as they originally

Answer 1

The correct option is C Cell Y will turn blue-black

• Iodine test is a test done to test the presence of starch in the given sample. If starch is present in the sample, the blue-black colour is developed upon the addition of iodine solution.
• Chloroplasts are the organelles present in the photosynthetic algae and plants. They synthesis carbohydrates by the process of photosynthesis. When chloroplast is removed from the algae X, no photosynthesis will take place even after keeping it in bright sunlight. Hence, the cell X will not turn blue-black in colour.
• However, when algae Y is kept under bright sunlight, photosynthesis takes place and starch is produced. Hence, cell Y will turn blue-black upon the addition of iodine solution.

Thus, the correct answer is 'Cell Y will turn blue-black.'