plants for their food. But how do plants carry out their life processes?
Scientists have been working for centuries to find out how plants carry
out these life processes. We know that among all life processes, the process
of photosynthesis makes plants “the universal food providers” for all living
organisms.
You have studied something about photosynthesis in your earlier
classes. Von Helmont and other scientists believed that plants get their
food material not only from soil but also from other sources.
Can you name some raw materials needed for photosynthesis?
What could be the end products of the process of photosynthesis?
Let us study the process of photosynthesis in detail.
Photosynthesis is the process by which
plants containing the green pigment
‘chlorophyll’ build up complex organic
molecules from simple inorganic ones,
using sun light as an energy source.
The
process of photosynthesis is very complex.
Several reactions takes place in this process
and intermediate compounds are also
formed. Scientists had tried to formulate a
simple equation to indicate photosynthesis
over 200 years.
The equation that is used
widely is formulated and proposed by
C.B. Van Neil in 1931 .
His opinion was,
“for each molecule of carbohydrate formed, one molecule of water and
one molecule of oxygen is produced”.
Though photosynthesis is a very
complex process, we use the following simple equation.
CO2
+ 2H2
O CH2
O + H2
O + O2
What would be the reaction to show that glucose (C6
H12O6
) is being
synthesized? Write down a balanced equation to show this.
(Refer the lessons Chemical equations, Carbon and its compounds in
your textbook of physical science class X).