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Class IX
Biology
Chapter: The Fundamental Unit of Life
Notes

Cell is Fundamental Structural and functional unit of life
*Cell is called structural unit of life because all living organisms are made up of one
or more than one cell*
*Cell is called functional unit of life because cell performs all life based functions
like respiration, reproduction, digestion, absorption, excretion etc in our body*

When number of cells come together they
form tissues
...
When tissues come together they form organs (
eg
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Organs form organ systen ( eg
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And then ultimately new organism is formed
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(Cork is a substance which comes from bark of trees)
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Examples: Bacteria, Paramecium and Amoeba

Multicellular Organisms: The organisms that are made from more than one cell are
known as multicellular organisms
...

>> Some cells have fixed shape(eg
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Amoeba)
>> The cell is able to live, reproduce and perform all functions in
our body due to various cell organelle present inside the cell
>> Cell organelles are generally parts of cells
...
Similarly cell have also some specialised
parts to absorb, respirate, reproduce etc
...
Plasma Membrane Or Cell
Membrane:
>> It is the thin outermost covering present in
both plants and animal cells
>> It is known as selectively permeable membrane
because it allows entry and exit of some materials
in and out of cells
>> It is composed up of lipids and proteins
>> It is living cell organelle
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Solid, Liquid, Gas)

from region of high concentration to low concentration until they
spread evenly is called Diffusion
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The amount of oxygen is
greater outside cell and is lesser inside the cell
...
e high quantity to low concentration i
...
So oxygen will get inside cell
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The concentration of carbon dioxide is
more inside cell than outside
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There is one more process for entry and exit of
substance which is different from Diffusion and
that is OSMOSIS
OSMOSIS: The

movement of water molecules from region of

high water concentration to low water concentration through
selectively permeable membrane is known as osmosis
...


Types of OsmosisEndosmosis: The process in which water enters the
cell is known as endosmosis
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Exosmosis: The process in which water leaves the
cell is known as Exosmosis
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Types of solutions-

Hypertonic Solution: When we dissolve more solute
(eg
...

Or
When the solution has more concentration of solute
than solvent in beaker it forms hypertonic solution

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