Photosynthesis Process

Photosynthesis is the process of capturing light energy and transforming it into chemical energy. Green plants and several other organisms use light energy and convert carbon dioxide and water into glucose. In this process, oxygen is produced as a by-product. 

Photosynthesis process step by step conducts these reactions and maintains the balance of oxygen and carbon dioxide in the atmosphere. However, photosynthesis in plant leaves usually occurs in two ways. These are light-dependent reactions and light-independent reactions or dark reactions. 

Light-Dependant Reaction

This process happens in the thylakoid membrane and needs a constant supply of photons or light energy. Chlorophylls use this energy and produce ATP and NADPH. Water molecules are transformed into oxygen through this process. 

Light-Independent Reaction

This reaction happens in the stroma and can take place in the absence of light. It takes up ATP and NADPH produced from light reaction to break down carbon dioxide. This process helps in forming three types or carbon-sugars that creates glucose. 

Let’s understand the photosynthesis process step by step!

Step by Step Procedure of Photosynthesis

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Fig: Process of photosynthesis

Plant leaves absorb the photons from sunlight that excite chlorophyll and activate electrons. In the first step, the water absorbed by plant roots is split into oxygen and hydrogen ions. 

Then the excited electrons form ATP and NADPH. This process happens through the electron chain. Likewise, in this process, oxygen is released in the atmosphere through leaves. 

In the next step, the energy from light reaction transforms carbon dioxide into glucose. This whole process takes place in several stages. The series of reactions start with 3-Ribulose biphosphate (RuBP) and ends with the same molecule forming glucose. The Rubisco enzyme is an essential component of this Calvin Cycle that initiates all the reactions. 

All the significant reactions of photosynthesis process generally take place during day time in the chloroplasts of leaves. 

Following is the fundamental equation of photosynthesis

 6CO₂ + 6H₂O (+ light energy) → C₆H₁₂O₆ + 6O₂

This is the overall overview of how photosynthesis process step by step takes place. 

Factors that Affect Photosynthesis

Following is the list of factors that influence the rate of photosynthesis.

• Temperature and Light Intensity 

Generally, with higher light and temperature intensity, the rate of photosynthesis increases. However, after a specific intensity of light, this rate saturates. It solely depends on the growing condition and species of the plants. 

• Water 

The rate of photosynthesis depends on a steady water supply. A minimal amount of water is required to conduct the reactions. The maximum amount of water transpires through stomata of leaves. 

In arid areas, therefore, the opening and closing of stomata are limited. This allows reserving the water supply and overall temperature of leaves. 

• Carbon Dioxide 

The concentration of carbon dioxide influences mainly the dark reactions of photosynthesis. Hence, this rate increases with the increased supply of carbon dioxide. 

• Minerals

A few minerals like potassium, iron, magnesium, phosphate, etc. are essential for plant growth. They also hasten the rate of photosynthesis of plants. 

Apart from that, a few other factors like environment, species, etc. affect the rate of photosynthesis. 

Importance of Photosynthesis

• Introduce energy and fixed carbon into the ecosystem.

• Reduce a large quantity of carbon dioxide from atmosphere. 

• Produces oxygen that sustains all the life. 

Pop Quiz 

1. Photosynthesis is a/an _______________ process.

2. _______________ colour of light is responsible for photosynthesis in bacteria. 

3. Which metal is present in both chlorophyll “a” and “b”?

1. Magnesium

2. Iron

3. Manganese 

4. Copper

4. Chlorophyll is the structural unit of photosynthesis. True/False.

Answers: 1- Anabolic, 2-Red, 3-a), 4- False.

For more information regarding photosynthesis process step by step, go through the course materials available in our website! You can also join live online classes via Vedantu’s app.