Question

The diagram alongside shows two test tubes A and B. Test tube A contains a green water plant. Test tube B contains both, a green water plant and a snail. Both test tubes are kept in sunlight.

Answer the questions that follow

1. Name the physiological process that releases the bubbles of oxygen.
2. Explain the physiological process as mentioned above in (1).
3. What is the purpose of keeping a snail in test tube B?
4. Why does test tube B has more bubbles of oxygen?
5. Give an example of a water plant, that can be used in the above experiment.
6. Write the overall chemical equation for the above process.

Answer 1

1. The process that releases the bubbles of oxygen:

1. Photosynthesis is the process due to which bubbles of oxygen are released in the test tube.
2. The plant submerged in water is doing photosynthesis in the presence of sunlight which results in the emergence of oxygen gas.

2. Explanation of the physiological process going on in the test tube:

1. Photosynthesis is the process occurring in the given test tube.
2. Photosynthesis is the process by which plants convert light energy into chemical energy in order to generate oxygen and sugar molecules by combining water, and carbon dioxide in the presence of sunlight.

3. Purpose of keeping snail in the test tube B:

1. Snails, through the act of respiration, will exhale ${\mathrm{CO}}_2$ and so give carbon dioxide for the photosynthetic process.
2. The goal of maintaining the snail in test tube B is to produce carbon dioxide for the plant to use.

4. Reason for more bubbles in test tube B:

1. Test tube B has more oxygen bubbles because it has a higher rate of photosynthesis because it receives more ${\mathrm{CO}}_2$ released by the snail during respiration.

5. Example of a water plant that can be used in the above experiment:

1. Hydrilla can be used in the above experiment.
2. It is because Hydrilla is a water-submerged plant that does not have stomata for gaseous exchange.
3. Both oxygen and carbon dioxide gases can diffuse through its body surface freely.

6. The overall chemical equation for the physiological process:

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