Saturday, 11 March 2017


The processes by which plants and many types of bacteria prepare their food by using sunlight.


The main pigment which play important role in photosynthesis is green color pigments known as chlorophyll.

Where photosynthesis take part in Plants ?

Photosynthesis take place in only leaves of the plants. These leaves are also known as solar collector because they trap sunlight from sun directly by convert
ng sunlight into chemical energy.

Raw Materials of Photosynthesis

1.      Water  (H2O)
Water comes from earth by roots of plants.
2.      Carbon Dioxide (CO2)
Carbon dioxide comes from atmosphere.
How Food is prepared ?                                                
First of all, water comes from underground water resources with the help of roots of plants and Carbon dioxide comes from atmosphere. These two compounds mix together with the help of sunlight to form glucose molecules and oxygen is also released during this processes.  The processes of photosynthesis start in chloroplast region of plant which contains proteins that absorb sunlight from sun.  Such proteins are also present in the plasma membrane of bacteria. Plants store energy in the form of sugar. Plants are known as photograph's which means the plants are able to prepare their food directly from sunlight and in the presence of water and carbon dioxide. During the processes of photosynthesis, oxygen is also released which released in the atmosphere.

How sunlight change into chemical energy?

The green pigment chlorophyll is responsible of conversion of sunlight into chemical energy to start a photosynthetic reaction. Chlorophyll is a complex and have different types such as a, b, c etc but, chlorophyll a is responsible of conversion of sunlight into chemical energy and it also absorb energy from orange-red  and violet-blue wavelengths.

Structural form of Photosynthetic Parts


The main green part of plant where photosynthetic processes take place is known as chloroplast. It contains main green pigment chlorophyll which play important role in forming food.  This portion has a pure green color. One plant contains 8 to 100 chloroplasts which are enclosed in phospholipids membranes.

Chloroplast Parts

1.       Two membranes
            Outer and inner membranes are present.

2.       Grana
Grana is composed of thylakoids which are disc shaped and are present in stacks.

3.       Stroma
The matrix in which grana is present is known as stroma. It is a fluid like region.

4.       Ribosome’s
      Ribosomes are also present in chloroplast.

5.       Starch
Starch is also present.

Why chloroplast is green in color?
The chloroplast is green in color due to presence of chlorophyll.

Reaction Types
There are two types of reactions which take place in plants during processes of photosynthesis which are given below,

1.       Light Reaction
This reaction takes place in the presence of light   in the grana region of chloroplast. During light reaction, ATP and NADPH are formed.

2.       Dark reaction
This reaction takes place in absence of light in stroma region of chloroplast during night. During dark reaction only ATP is formed.

photosynthesis define

Writer Muhammad Sulaiman

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Hello students, Computer Science mcqs in pdf will be share tomorrow.
Thanks You
NTs Teacher

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