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. Tissues are group of cells. When tissues come together they form organs (
eg. Heart, liver, stomach). Organs form organ systen ( eg. Respiratory system, digestive
system). And then ultimately new organism is formed.
Discovery of Cell
,Robert Hooke while examining a thin slice of cork saw that cork resembled the
structure of honeycomb consisting of many compartments.
(Cork is a substance which comes from bark of trees).
, Schleiden, Schwann and Virchow Expanded cell theory
Types of Organisms on the
basis of number of cells
Unicellular Organisms: The organisms that are made from one cell are known as
unicellular organisms.
Examples: Bacteria, Paramecium and Amoeba
Multicellular Organisms: The organisms that are made from more than one cell are
known as multicellular organisms.
Examples: Animals, Plants And Human beings
Some Points to remember:
>> The Shape and size of cells depends on specific functions they
perform.
>> Some cells have fixed shape(eg. Nerve cell) And some cells
have changing shapes(eg. 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. Eg Humans have
some parts like heart to pump blood or lungs to respirate and
stomach to digest food. Similarly cell have also some specialised
parts to absorb, respirate, reproduce etc.
Parts of cell–
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. Tissues are group of cells. When tissues come together they form organs (
eg. Heart, liver, stomach). Organs form organ systen ( eg. Respiratory system, digestive
system). And then ultimately new organism is formed.
Discovery of Cell
,Robert Hooke while examining a thin slice of cork saw that cork resembled the
structure of honeycomb consisting of many compartments.
(Cork is a substance which comes from bark of trees).
, Schleiden, Schwann and Virchow Expanded cell theory
Types of Organisms on the
basis of number of cells
Unicellular Organisms: The organisms that are made from one cell are known as
unicellular organisms.
Examples: Bacteria, Paramecium and Amoeba
Multicellular Organisms: The organisms that are made from more than one cell are
known as multicellular organisms.
Examples: Animals, Plants And Human beings
Some Points to remember:
>> The Shape and size of cells depends on specific functions they
perform.
>> Some cells have fixed shape(eg. Nerve cell) And some cells
have changing shapes(eg. 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. Eg Humans have
some parts like heart to pump blood or lungs to respirate and
stomach to digest food. Similarly cell have also some specialised
parts to absorb, respirate, reproduce etc.
Parts of cell–
