Question

The following diagram demonstrates a physiological process taking place in green plants.

The whole set-up was placed in bright sunlight for several hours. Study the diagram and answer the questions that follow

1. What aspect of the physiological process is being examined?
2. Explain the physiological process mentioned in (1) above.
3. Lable parts A and B in the diagram.
4. Write a well-balanced chemical equation for the physiological process explained in (2) above.
5. What would happen to the rate of bubbling of the gas if a pinch of sodium bicarbonate is added to the water in the beaker? Explain your answer.

Answer 1

Experimental Setup:

1. The given experiment was done to demonstrate that oxygen is released during photosynthesis reaction.
2. An aquatic plant, like Hydrilla, was placed in a beaker having pond water.
3. The plant was covered by inverting a short-stemmed funnel on it.
4. A test tube containing water was used to cover the stem of the funnel.
5. It was ensured that the water level in the beaker is above the level of the funnel's stem.
6. The whole setup was kept in sunlight for a few hours.
7. It was observed that bubbles were produced in the test tube and when it was tested with a glowing splinter, it was found that oxygen is present above the test tube.

1. Aspect tested during the experiment:

1. In this experiment, the production of oxygen gas during photosynthesis was tested.

2. Physiological process mentioned in the experiment:

1. Photosynthesis is the plant's physiological phenomenon in the given experiment.
2. Photosynthesis is a process that occurs in autotrophs like green plants. In the availability of sunlight, carbon dioxide, and chlorophyll, plants use this process to prepare carbohydrates and oxygen.

3. Labeling of parts of the given apparatus:

1. In the given figure, A is the gas (oxygen). It is produced by the photosynthesis reaction of the green aquatic plant.
2. The part of the apparatus labeled as ‘B’ is Hydrilla (a green aquatic plant). It is the plant that is performing photosynthesis.

4. A well-balanced chemical equation for the physiological process mentioned above:

$$\begin{gathered} 6{\mathrm{CO}}_2+6{\mathrm{H}}_2\mathrm{O}\to {\mathrm{C}}_6{\mathrm{H}}_{12}{\mathrm{O}}_6+6{\mathrm{O}}_2 \\ \mathrm{Carbon}\mathrm{Water}\mathrm{Glucose}\mathrm{Oxygen} \\ \mathrm{dioxide} \end{gathered}$$

5. Change occurs upon addition of sodium bicarbonate:

1. When a pinch of sodium bicarbonate is added, the rate of gas bubbling increases dramatically.
2. Carbon dioxide is released into the water by sodium bicarbonate, which is then accessible to the plant.
3. The rate of photosynthesis is increased as a result of this. As a result, more oxygen is released, resulting in more bubbles.