Significance of Photosynthesis: Definition, Products, Diagram

Significance of Photosynthesis: At least half of the oxygen generated on Earth originates from the ocean via phytoplankton photosynthesis, with the other half produced on land through photosynthesis by trees, shrubs, grasses, and other plants. Photosynthesis produces oxygen, which is released into the atmosphere through stomata, tiny pores in the leaves. All life on Earth would end if there were no green vegetation. Cyanobacteria and other photosynthetic microorganisms also carry out photosynthesis.

In this article, students will learn the importance of photosynthesis along with parts of the plant involved in photosynthesis. After going through this entire article, students will be able to write the significance of photosynthesis in their exams effortlessly.

Definition of Photosynthesis

Photosynthesis (Gk. photon \({\rm{ = }}\) light; Synthesis \({\rm{ = }}\) putting together) is the most important anabolic process on our planet by which autotrophic organisms like plants synthesize complex carbohydrates from simple inorganic substances like carbon dioxide and water with the help of light energy. Carbon dioxide is fixed into carbohydrates, and light energy is converted into chemical energy.

Definition of Photosynthesis – Photosynthesis is the process of conversion of photonic energy into chemical energy by green plants.

Fig: Plant Capturing Light Energy to Perform Photosynthesis

Plants take in carbon dioxide and water in the presence of sunlight and convert them into glucose and oxygen. Oxygen is released into the atmosphere, and glucose is used for the growth and development of plants. So, plants make their food with inorganic substances in the presence of sunlight.

Fig: Equation of Photosynthesis

Parts of Plant Involved in Photosynthesis

1. Green parts of the plants like leaves, sepals and young stems are involved in photosynthesis.
2. Its cells contain organelles called Chloroplast.
3. Chloroplast (Chloros \({\rm{ = }}\) green, plastos \({\rm{ = }}\) moulded) is the green plastid that occurs in green parts of the plant.
4. Chloroplasts are mainly contained in the mesophyll cells located between the upper epidermis and lower epidermis of leaves.
5. It has a green pigment called chlorophyll (Chlor \({\rm{ = }}\) green, phyll \({\rm{ = }}\) leaf).
6. Chloroplast is a double membranous structure.
7. This envelope encloses a matrix called stroma, which contains all the necessary enzymes of photosynthesis.
8. Within the stroma, there are flattened sac-like lamellae called thylakoids, which are stacked at some places to form grana.
9. There may be \(40-50\) chloroplasts in a cell.
10. The major function of thylakoids is to perform photosynthetic light reactions.
11. Stroma is the site of dark reactions of photosynthesis.
12. Too much light destroys chlorophyll. However, the formation of chlorophyll depends upon exposure of sunlight.

Fig: Structure of Chloroplast

Products of Photosynthesis

The product of photosynthesis is glucose which is used by plants as food, and the by-product is Oxygen. These are formed from raw materials – carbon dioxide, water and sunlight. This process helps in purifying the atmosphere by consuming carbon dioxide and evolving oxygen.

Fig: Products of photosynthesis

What is Significance of Photosynthesis?

Photosynthesis is one of the most important processes in the ecosystem. It is due to the following reasons:-

1. Provides Food: Each and every organism is dependent on plants, either directly or indirectly. We, humans, are also dependent on plants. Herbivores like cows, goats are directly dependent on plants, while carnivores like tigers, lions are indirectly dependent on plants. So, it can be said that herbivores are dependent on autotrophs directly while carnivores are dependent on herbivores, indirectly on plants. This chain of food dependency is called a food chain. Photosynthesis is a vital process and is responsible for the growth and sustenance of the biosphere.
2. Provides Oxygen: Photosynthesis is the only process by which oxygen is evolved which is used by other organisms and plants themselves for respiration. Photosynthesis in plants is necessary to maintain the oxygen levels in the atmosphere.

Fig: Oxygen Available for Respiration

3. Ozone \(\left( {{{\rm{O}}_3}} \right)\) Formation: Molecular \({{\rm{O}}_{\rm{2}}}\) released from photosynthesis is also utilized in making ozone in the outer layer of the atmosphere. This ozone layer does not allow harmful, destructive ultraviolet radiations to get into our atmosphere. These UV rays may cause skin cancer and other related chronic diseases.
4. Formation of Carbohydrates: Carbohydrates are formed during this process which is stored in the plant body as starch and act as a food reserve, while in animals, it is stored as glycogen.
5. Formation of other Metabolites: The carbohydrates produced during photosynthesis are used by plants and animals to synthesize organic acids, proteins, fats, nucleic acids, pigments, vitamins, and other metabolites.
6. Balances \({\rm{C}}{{\rm{O}}_{\rm{2}}}\) in the Atmosphere: \({\rm{C}}{{\rm{O}}_{\rm{2}}}\) is the raw material for photosynthesis, and thus, this process helps in the removal of \({\rm{C}}{{\rm{O}}_{\rm{2}}}\) or carbon dioxide from the atmosphere, which is being added by the respiration process in us, burning of fossil fuels, etc.
7. Contribution to Carbon Cycle: Photosynthesis is responsible for the growth and sustenance of the biosphere, and the products of photosynthesis contribute to the carbon cycle occurring in the oceans, land, plants, and animals.
8. Fossil Fuels: These are the products of photosynthetic organisms, i.e. plants, algae, phytoplanktons which formed by the decomposition of these organisms when they died.
9. Other Products of Photosynthesis: In addition to organic food, plants yield fodder, firewood, timber, fibres, rubber, resins, oils, etc.

Summary

Photosynthesis is defined as a process that occurs primarily in chloroplasts and is mediated by photosynthetic pigments such as chlorophyll a, chlorophyll b, carotene, and xanthophyll. Photosynthesis uses carbon dioxide, water, and sunshine to create nutrition in green plants and a few other autotrophic species. The process of photosynthesis produces oxygen as a by-product.

Photosynthesis is the most important anabolic process on our planet by which autotrophic organisms like plants synthesize complex carbohydrates from simple inorganic substances like carbon dioxide and water with the help of light energy. Green parts of the plants like leaves, sepals and young stems are involved in photosynthesis. It has much importance like it provides food for all organisms directly or indirectly. It provides oxygen for respiration to aerobic organisms. This process also helps in balancing carbon dioxide in the atmosphere.

Also, it helps in the formation of primary and secondary metabolites which are used by different organisms for their growth and development. So, it can be concluded that photosynthesis is an essential process without which all life would come to an end.

Frequently Asked Questions (FAQs) on Significance of Photosynthesis

Q.1. What is the significance of photosynthesis?
Ans: i. It provides food for all organisms either directly or indirectly.
ii. It provides oxygen to aerobic organisms for respiration.
iii. It balances \({\rm{C}}{{\rm{O}}_{\rm{2}}}\) in the atmosphere.

Q.2. Why is photosynthesis significant to plants?
Ans: Photosynthesis significant to plants as this process helps in the formation of sugar which plants use for their growth and development. Also, it releases oxygen which is used by plants for respiration.

Q.3. What role does sunlight play in photosynthesis?
Ans: Sunlight provides energy for the process of photosynthesis.

Q.4. How does photosynthesis affect humans?
Ans: Photosynthesis provides oxygen to humans for their respiration. Also, carbohydrates produced by the plants are used as an energy source for humans. Excess of it is stored as glycogen for future use.

Q.5. Does photosynthesis produce oxygen?
Ans: Yes, photosynthesis produces oxygen.

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