Download A LIFE PROCESSES PHOTOSYNTHESIS

A
CLASS-X
EPISODE – 1
STATE SYLLABUS
LIFE PROCESSES
PHOTOSYNTHESIS
The subject of Biology deals with the study of plants and animals.
From the ancient to modern world, since the origin of life on this
planet earth to the present day,evolution has played a major role in
evolving new species. Every new species that evolved and those that
survived and perpetuated had more advanced characters and
phenomena. However the basic and fundamental features and
metabolic processes have not changed. This is the best evidence of
evolution.
All organisms have some basic processes. These processes are
important for the sustenance and perpetuation of an organism. They
are termed as Life processes. They can be classified into three main
groups.
1) Processes for Maintenance
a) Digestion
b) Respiration
c) Transport
d) Excretion
2) Control and Co-ordination
a) Nervous system
b) Sense organs
c) Endocrine system
3) Reproduction
We have learnt in the earlier classes that there are unicellular and
multicellular organisms. While the unicellular organisms remain as a
single cell, the multicellular organism begins life as a single cell the
zygote. This zygote multiplies and adds more cells. Then it grows into
an adult. For all the above processes the organisms requires raw
materials. When we build a house we need a number of materials.
Can we create them out of nothing?
In the same way the organism has either to produce or synthesize or
procure the material required for growth from other sources. The
organism require food for the raw materials.
These raw materials have to be transported to the regions of growth.
For example for the synthesis of protein the organism requireds amino
acids. Very few amino acids can be synthesized in the body. Rest of
the amino acids have to be procured from food. The proteins in the
food are broken down in the body to amino acids in the process of
digestion. These amino acids are transported to tissues by the
transport system. In the cells they are used to synthesize proteins.
During this process the wastes are eliminated by the excretory
system.
For all the above activities energy is required. For production of
energy oxygen is required. This is looked after by the respiratory
system.
All the above activities have to be under control and proper
coordination. This is looked after by the constituents of control and
coordination system. Only when all the systems are functioning
normally the organism grows and develops.
How do organisms obtain energy from food?
We know that plants of AUTOTROPHS. They prepare their own food
by the process of PHOTSYNTHESIS. The sun light plays a major role
in Photosynthesis. In this process simple inorganic elements like
carbon, hydrogen and oxygen are converted to complex organic
substances.
Photosynthesis is the only process that utilizes energy from sun to
produce food for millions of organisms. This is only process which
adds oxygen to the atmosphere.
This photosynthesis is the basic life process for the sustenance of
organisms in general and man in particular. Plants not only provide
food to us but also other useful products like wood for shelter and
fossil fuels like coal, wood and petroleum products are products of
plants.
Respiration is important in releasing energy. It is stored in
carbohydrates which in turn are synthesized during photosynthesis.
These processes prove the co-ordination between the systems.
Photosynthesis as a life process:How do plants synthesize their own food?
Plants produce their own food by a process called photosynthesis.
Hence they are called AUTOTROPHS.
Where does this process occur?
Green leaves which have chlorophyll, the green pigment, are primary
organs for photosynthesis.