Gaseous exchange is how living things get the oxygen they need and get rid of carbon dioxide. Plants also use it to make food in a process called photosynthesis. Animals in water get their gases from water, while those on land get them from the air.
Plants, akin to animals, engage in critical processes that necessitate gaseous exchange. Despite lacking respiratory organs like humans, plants have evolved intricate mechanisms for the exchange of gases to sustain life. Two fundamental processes in plants, photosynthesis, and respiration, serve as primary drivers of this exchange. We shall explore and contrast these processes from a more professional standpoint.
| Aspect | Photosynthesis | Respiration |
|---|---|---|
| Function | Photosynthesis is akin to a culinary artist crafting sustenance for the plant. | Respiration operates as an internal powerhouse, generating energy. |
| Substrates | Photosynthesis utilizes carbon dioxide and harnesses sunlight as its core ingredients. | Respiration relies on oxygen and organic compounds, typically glucose. |
| Light Dependency | Photosynthesis is light-dependent, requiring the presence of sunlight. | Respiration, in contrast, occurs independently of light, functioning in both day and night. |
| Location | Photosynthesis primarily transpires within chloroplasts of plant cells, particularly in leaves. | Respiration is a ubiquitous process, transpiring in all living plant cells. |
| Gas Exchange | Photosynthesis assimilates carbon dioxide (CO2) and liberates oxygen (O2) as a byproduct. | Respiration involves oxygen (O2) intake and the release of carbon dioxide (CO2) as waste. |
| Temporal Pattern | Photosynthesis predominantly occurs during daylight hours. | Respiration, in contrast, operates continuously, devoid of diurnal variation. |
| Chlorophyll Role | Photosynthesis relies on chlorophyll, a pigment, to capture and convert sunlight into energy. | Respiration functions independently of chlorophyll, making it a universal process. |
In summary, photosynthesis acts as a culinary artisan, harnessing carbon dioxide, sunlight, and chlorophyll to create sustenance, while respiration serves as a tireless, energy-generating powerhouse that operates continuously in all plant cells. Together, these processes sustain the vitality of the plant kingdom.
Stomata, or “mouths” of leaves, are microscopic openings controlled by guard cells, enabling plants to exchange gases with the environment. They open during the day, taking in carbon dioxide and releasing oxygen, thanks to increased guard cell turgidity from photosynthesis. At night, they close when photosynthesis ceases.
The effect of light on the net gaseous exchange from leaf by using Hydrogen bicarbonate as indicator.
Hydrogen bicarbonate is an indicator for carbon dioxide. Its colour turns as follows according to the level of carbon dioxide:
PHOTOSYNTHESIS | RESPIRATORY |
HIGHEST | YELLOW |
HIGH | ORANGE |
ATMOSPHERIC LEVEL | RED |
LOW | MARGENTA |
LOWEST | PURPLE |
Four test tubes, test tube stand, aluminum foils or black paper, tissue paper, fresh green leaves, four corks, wax, thread, glass marking pencil
Test tube 1: The indicator will turn yellow, indicating the highest rate of photosynthesis and the lowest rate of respiration.
Test tube 2: The indicator will turn orange, indicating a high rate of photosynthesis and a low rate of respiration.
Test tube 3: The indicator will turn red, indicating the lowest rate of photosynthesis and the highest rate of respiration.
Test tube 4: The indicator will turn magenta, indicating a low rate of photosynthesis and a high rate of respiration.
Q1. Is there any change of coloration of Hydrogen bicarbonate indicator?
ANS: Yes, hydrogen bicarbonate indicator can change color depending on the concentration of carbon dioxide in a solution.
Q2. What account for these changes?
ANS: Hydrogen bicarbonate indicator changes color depending on the concentration of carbon dioxide. This can be used to measure the rate of photosynthesis and respiration in plants.