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Title: class 9 ch1 Notes biology
Description: I hope these notes is helpful to you
Description: I hope these notes is helpful to you
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CLASS 9th- THE FUNDAMENTAL UNIT OF LIFE – ANWAR ACADEMY
Chapter Overview:
Topics to be Covered:
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The Fundamental Unit of Life: Cell
What is a Cell Made Up of? What is the Structural
Organization of a Cell?
Cell Theory
Prokaryotic and Eukaryotic Cell
Structure of Cell
Plasma Membrane
Cell Wall
Nucleus
Cell Division ( Mitosis and Meiosis)
CLASS 9th- THE FUNDAMENTAL UNIT OF LIFE – ANWAR ACADEMY
Cell division:
• Mitosis
• Meiosis
CLASS 9th- THE FUNDAMENTAL UNIT OF LIFE – ANWAR ACADEMY
Cell - Definition
Represents
Represents
“Building blocks of life”
“Fundamental unit of life”
“Structural of functional of Life”
CLASS 9th- THE FUNDAMENTAL UNIT OF LIFE – ANWAR ACADEMY
Cell Discovery:
• First discovered by Robert Hooke in 1665
• Observed cork
• Cork is obtained from bark of tree
Cork
Cork under microscope
CLASS 9th- THE FUNDAMENTAL UNIT OF LIFE – ANWAR ACADEMY
Cell Discovery
• Observation
Honeycomb Compartments
Derived the name cell from Latin word
Meaning
Small room
CLASS 9th- THE FUNDAMENTAL UNIT OF LIFE – ANWAR ACADEMY
Cell Discovery:
Some other discoveries:-
Leeuwenhoek
living cells in pond water
Robert Brown
Nucleus
Purkinje
1674
1831
1839
Protoplasm
Cell Theory
Presented by 2 biologists
Schleiden (1838)
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Schwann (1839)
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"All the plants and animals are composed of cells"
"Basic unit of life is cell“
Expended by Virchow (1855)
"Cells
arise from pre-existing cells"
Free
CLASS 9th- THE FUNDAMENTAL UNIT OF LIFE – ANWAR ACADEMY
Parts of Cell: Cell Membrane/Plasma Membrane
Characteristics:
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Thin, elastic/flexible
Living
Outermost covering
Holds the content of cell
Provides a definite shape
Water Filled Balloon
Facilitates movement of some material because it is
selectively permeable
• Composed of organic molecules (Lipids + Proteins)
• Flexibility enables the cell to engulf
• Engulf --> Food/other materials from external
environment
CLASS 9th- THE FUNDAMENTAL UNIT OF LIFE – ANWAR ACADEMY
Movement Across Cell Membrane
• 1
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• Rate of diffusion Gases > Liquids > Solids
• Showed by small size substances
Examples: ions/molecules, CO2, Oxygen, Water
• Due to cellular activities, CO2, production takes place
...
Osmosis
• Movement of water from higher
concentration to lower
• Cell absorbs water through osmosis
• No energy is required
• Process lasts up to equilibrium state
Plasmolysis - Shrinkage of living plant cell
due to exosmosis
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Nucleolus
One or more in numbers
From protein forming centres – Ribosomes
B
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During cell division, chromatin material gets
organised into chromosomes
Chromatin material
CLASS 9th- THE FUNDAMENTAL UNIT OF LIFE – ANWAR ACADEMY
Chromosome
Thread like structure
Visible during cell division
Components
DNA
(Deoxyribonucleic acid)
Protein
(Histones)
DNA consist of genes
Functional segment of DNA are called genes
Genetic information is transfer from one generation to next
CLASS 9th- THE FUNDAMENTAL UNIT OF LIFE – ANWAR ACADEMY
Chromosome
CLASS 9th- THE FUNDAMENTAL UNIT OF LIFE – ANWAR ACADEMY
Parts of Cell : Cytoplasm
Parts between plasma membrane and nuclear envelope
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CLASS 9th- THE FUNDAMENTAL UNIT OF LIFE – ANWAR ACADEMY
Types of Cell:
Prokaryotic Cell
Eukaryotic Cell
Size (1 - 10μm)
Size (5-100μm)
Nucleus absent
Nucleus present
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Nucleolus present
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Chromosome - Single
Title: class 9 ch1 Notes biology
Description: I hope these notes is helpful to you
Description: I hope these notes is helpful to you