Question

Write any five significances of photosynthesis.

Answer 1

Hint: Green plants, algae, and some other organisms carry out 'photosynthesis’ reactions. It is a physicochemical process by which they use light energy to drive the synthesis of organic compounds. This is the basis of life on earth.

Complete step-by-step answer:
In photosynthesis, plants use sunlight, water, and carbon dioxide from the air to make glucose and oxygen. This glucose is a form of sugar that plants need to survive. Photosynthesis is represented by the equation:
$6CO_{ 2\quad }+\quad 12H_{ 2 }O\quad \xrightarrow [ Sunlight ]{ Chlorophyll } \quad C{ _{ 6 }{ H }_{ 12 } }{ O }_{ 6 }\quad +\quad 6{ H }_{ 2 }O\quad +\quad 6{ O }_{ 2 }$
where,
$C{ _{ 6 }{ H }_{ 12 } }{ O }_{ 6 }$ represents glucose
$C{ O }_{ 2 }$ represents carbon dioxide
${ H }_{ 2 }O$ is water, and
$O_{ 2 }$ is Oxygen.
significance of photosynthesis:
- It is the primary source of all food on earth.
- It helps convert solar energy into organic matter.
- It is also responsible for the release of molecular oxygen into the atmosphere by green plants.
- This evolved oxygen is consumed by other living organisms which helps maintain the levels of atmospheric oxygen.
- Photosynthesis utilizes atmospheric carbon dioxide and yields carbohydrates like glucose.
- The produced carbohydrates are used by plants and animals to synthesize organic acids, hormones, vitamins, alkaloids, and other metabolites.
- Moreover, an excessive rise or fall in the level of carbon dioxide can bring forth disastrous results on the planet earth. This level of carbon dioxide in the atmosphere depends on photosynthesis, which in turn depends on the number of plants we have.
- Leaves are the most important vegetative organs for photosynthesis. However, this phenomenon also takes place in other green parts of the plants.
- Within the leaves, the site for this phenomenon is ground tissue consisting of parenchyma along with other tissue.
- Mesophyll, which possesses chloroplasts and carries out photosynthesis, is made up of parenchyma.
- These chloroplasts contain chlorophyll and carotenoid pigments that are responsible for trapping light energy essential for photosynthesis.
So, ultimately all the food that is respired for life processes comes from photosynthesis. During this process, carbon dioxide from the atmosphere is taken in by leaves through stomata and used for making carbohydrates, primarily glucose, and starch. It is also accompanied by the release of oxygen which is further utilized by other living organisms.

Note: Some plants like Opuntia or Euphorbia of arid regions modify their stems into flattened or fleshy cylindrical structures. They contain chlorophyll and carry out photosynthesis. Chemosynthesis is a different process where the reduction of carbon dioxide to carbohydrates does not require light. Examples of organisms showing this method of energy production are nitrifying bacteria, sulphur bacteria, etc.