process of photosynthesis give the answer long?
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Photosynthesis is a biological process used by plants to prepare food with the help of sunlight water and carbon dioxide. The name photosynthesis is derived from the Greek word ”Photo” meaning light and “Synthesis” meaning connecting together. This means combining together with the help of light energy.
Leaves are made up of small cells which have a tiny structure known as chloroplasts. Each chloroplast contains a green colored pigment called chlorophyll. Light energy is absorbed by chlorophyll molecules whereas carbon dioxide (CO2) and oxygen (O2) enter through the tiny pores of stomata located in the epidermis of leaves.
Oxygen is considered one of the most important by-products of this process on which most of the living organism depend upon. Glucose/Sugar is a form of carbohydrates that is processed during the process of photosynthesis. It is commonly used by green plants in the form of an energy source to produce leaves, fruits, flowers, and seeds. The glucose molecules then combine with each other to develop more complex carbohydrates like cellulose and starch. The cellulose is considered as the structural material that is used in plant cell walls. The overall reaction of photosynthesis process is:
6CO2 + 6H2O —-> C6H12O6 + 6O2
Where does Photosynthesis occur?
Photosynthesis occurs mainly in leaves of specialized cell structures known as chloroplasts.
A leaf comprises a petiole, epidermis and a lamina.
The Lamina is used for absorption of sunlight and carbon dioxide during the process.
This process that occurs, takes place in chloroplasts that contain a green colored pigment called chlorophyll which is mainly responsible for green colored leaves.
During the process of photosynthesis, chlorophyll absorbs the light energy from the sun to split water molecules into hydrogen and oxygen.
The hydrogen from water molecules and carbon dioxide absorbed from the air are used in the production of glucose and the oxygen is liberated into the atmosphere through the leaves.
Glucose is a source of food for plants which provide energy for the growth and development, while the rest is stored in the roots, leaves, or fruits for their later use.
Photosynthesis comprises two phases.
Light-dependent reaction (or) Light reaction.
Photosynthesis begins with the light reaction which is carried out only during the day in the presence of sunlight. In plants, the light-dependent reaction takes place in the thylakoid membranes of chloroplasts. The Grana, membrane-bound sacs like structures present inside the thylakoids functions by gathering light and is called as photosystems. These photosystems have large complexes of pigment and proteins molecules present within the plant cells which plays the primary role during the process of light reactions. There are two types of photosystems: photosystem I and photosystem II.
Under the light-dependent reactions, the light energy is converted to ATP and NADPH which are used in the second phase of photosynthesis. During the light reactions, ATP and NADPH are generated by two electron transport chains, water is used and oxygen is produced.
The chemical equation in the light reaction can be reduced to:
2H2O + 2NADP+ + 3ADP + 3Pi → O2 + 2NADPH + 3ATP
Light-independent reaction (or) Dark reaction.
Calvin cycle
Dark reaction is also called carbon-fixing reaction. It is a light-independent process in which sugar molecules are formed from the water and carbon dioxide molecules. The dark reaction occurs in the stroma of the chloroplast where they utilize the NADPH and ATP products of the light reaction. Plants capture the carbon dioxide from the atmosphere through stomata and proceed to the Calvin cycle. In the Calvin cycle, the ATP and NADPH formed during light reaction drive the reaction and convert 6 molecules of carbon dioxide into one sugar molecule or glucose.
The chemical equation for the dark reaction can be reduced to:
3CO2 + 6 NADPH + 5H2O + 9ATP → G3P + 2H+ + 6 NADP+ + 9 ADP + 8 Pi
* G3P – glyceraldehyde-3-phosphate
Importance of Photosynthesis
It is essential for the existence of life on planet earth both as a source of food, shelter, and energy.
This process is responsible for supplying all of the earth’s organic compounds and the energy required to sustain life on the planet.
It is also responsible for maintaining and balancing the atmosphere’s oxygen and carbon dioxide levels and protects our planet from global warming
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