Photosynthesis – Introduction, Types, Process

Introduction 

Energy flow in ecosystem 

The food chain and food web facilitate the movement of energy. Plants collect sunlight with the aid of chloroplasts during the process of energy flow in the ecosystem, and a portion of it is turned into chemical energy in the process of photosynthesis. When herbivores eat (primary consumers) the plants as food, this energy is stored in various organic products in the plants and passed on to the primary consumers in the food chain. The chemical energy contained in plant products is then converted into kinetic energy, and energy is degraded by heat conversion.  

The flow of energy in the ecosystem is one of the most important variables in the survival of such a large number of creatures. Solar energy is the principal source of energy for practically all species on Earth. It’s amusing to learn that we only receive around half of the sun’s effective radiation on Earth. When we say effective radiation, we mean radiation that plants can employ to perform photosynthesis. 

Photosynthesis  

Photosynthesis is the conversion of light energy into chemical energy that occurs in green plants and certain other animals. Green plants use light energy to transform water, carbon dioxide, and minerals into oxygen and energy-rich organic molecules during photosynthesis.The energy produced by photosynthesis performed by plants millions of years ago is responsible for the fossil fuels (coal, oil, and gas) that power modern civilization.  

When plants use light energy to transform carbon dioxide and water into glucose and oxygen, this is known as photosynthesis. Chloroplasts are tiny cellular organelles found in leaves.Each chloroplast contains chlorophyll, a green pigment. Light energy is absorbed by chlorophyll molecules, while carbon dioxide and oxygen enter through stomata, which are microscopic pores in the epidermis of leaves. Sugars such as glucose and fructose are another byproduct of photosynthesis. 

Types of photosynthesis 

Photosynthetic processes are classified as either oxygenic or anoxygenic. They all work on the same principles, although oxygenic photosynthesis is the most frequent and is found in plants, algae, and cyanobacteria. 

Oxygenic photosynthesis 

Light energy transfers electrons from water (H₂O) taken up by plant roots to CO₂ to make carbohydrates during oxygenic photosynthesis. The CO₂ is “reduced,” or gains electrons, while the water is “oxidized,” or loses electrons, during this transfer. Carbohydrates and oxygen are both created. By absorbing CO₂ generated by all breathing creatures and returning oxygen into the atmosphere, oxygenic photosynthesis acts as a counterweight to respiration. 

The following equation may be used to illustrate this process: 

6CO₂+ 12H₂O + LIGHT ENERGY → C₆H₁₂O₆ +   6O₂ + 6H₂O 

Anoxygenic photosynthesis 

Anoxygenic photosynthesis is a phototrophic process that captures and converts light energy to ATP without producing oxygen; water is thus not required as an electron donor. Anoxygenic photosynthesis is performed by various types of bacteria, including green sulphur bacteria, green and red filamentous anoxygenic phototrophs. 

The following equation can be used to illustrate anoxygenic photosynthesis: 

CO₂ + 2H₂A + LIGHT ENERGY → [CH₂O] + 2A + H₂O  

Process of photosynthesis 

Photosynthesis happens at the cellular level in chloroplasts, which are cell organelles . These organelles carry a green pigment called chlorophyll, which is responsible for the leaves’ distinctive green color. As previously stated, photosynthesis takes place in leaves, and the specialized cell organelles responsible for this activity are known as chloroplasts.  

A leaf is composed of three distinct parts: a petiole, an epidermis, and a lamina . The lamina absorbs both sunlight and carbon dioxide during photosynthesis. Carbon dioxide enters the plant through the stomata, while water is taken by the root hairs from the soil and transferred to the leaves via the xylem vessels. Chlorophyll absorbs sunlight’s light energy and splits water molecules into hydrogen and oxygen. 

In the creation of glucose, hydrogen from water molecules and carbon dioxide taken from the air are required. Furthermore, as a waste product, oxygen is released into the environment via the leaves.Glucose is a fuel source for plants, providing energy for growth and development, with the remainder stored in the roots, leaves, and fruits for later use.  

Importance of photosynthesis 

• All life on Earth depends on photosynthesis to survive. It plays an important part in the food chain since plants use this mechanism to make food, creating the primary producers. 
• Photosynthesis is also responsible for the production of oxygen, which is essential for most creatures to survive. 
• The whole life form is directly or indirectly dependent on the photosynthesis process carried out by plants. Plants are unable to generate food if photosynthesis does not occur. As a result, they maintain environmental equilibrium.  
• Plants will cease to generate oxygen, and no animal life will be able to exist as a result of the lack of oxygen. We will run out of air and food, and all life on Earth will become extinct.