FUNDAMENTAL UNIT OF LIFE (1)

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Fundamental Unit of life
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Who discovered cell?

• Robert Hooke discovered cell in 1665
• Robert Brown discovered nucleus in a cell in 1831
• Leeuwenhoek discovered living cell in water in
  1674
• Purkinje discovered protoplasm in 1839
• Schleiden and Schwann discovered cell theory
• Virchow defined all cells comes from pre-existing
  cells

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Division of Labour

• There is division in multicellular organisms.
  This means that different body parts preforms
  different functions. Human body has a heart to
  pump blood, a stomach to digest food etc.
• Division of labour in Humans
• CELLS-gtTISSUES-gtORGANS-gtBODY

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3 Basic Features 
1) CELL MEMBRANE  2) CYTOPLASM3) NUCLEUS
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CELL MEMBRANE

• Outermost covering of cell
• It permits the entry and exit of some materials.
  Therefore it is called selectively permeable
  membrane
• Movement of gases is called diffusion 
• Movement of food is called endocytosis 
• Movement of water is called Osmosis
• High concentration to low
• Hypotonic- cell swell, gain water
• Isotonic- No net movement of water, same size
• Hypertonic- loose water, cell shrink
• Made up of lipids and proteins 

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PLASMOLYSIS 
Shrinkage of cytoplasm in hypertonic medium
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Cell wall

• Only plant cell
• Rigid outer covering
• Composed of cellulose
• Cellulose gives strength 
• Protect the plant 
• Gives shape to cell
• Cell wall of bacteria is not made up of cellulose

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Nucleus

• Centre of cell
• Darkly colored, spherical
• Double layer covering- Nuclear membrane
• Chromosomes -gt DNA
•                                  -gt PROTEIN 
• Allow transfer of material
• Genes functional unit of DNA

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Cytoplasm

• Jelly like structure
• Contain cell organelles

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Cell division 

• Mitosis-gt Cell division for growth
• Meiosis-gt Cell division for gametes

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Prokaryotes Eukaryotes

• Prokaryotes- Nuclear region not well defined
•                         It has single
  chromosomes 
•                         Cell organelles absent
• Eukaryotes- Nuclear region well defined
•                        More than one chromosomes
•                        Cell organelles present

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Vacuoles 

• Storage sacs
• Small size in animals
• Large size in plants
• Give rigidity
• Store amino acids and proteins
• Don't do locomotion 

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Plastids
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Golgi Apparatus
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Lysosomes
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Mitochondria

• Powerhouse
• 2 membrane coverings
• Inner membrane deeply folded
• Outer membrane is porous
• ATP is energy currency
• Own DNA and Ribosomes
• Own proteins

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ER
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FUNCTION OF ER

• It behaves as a transport channel for proteins
  between nucleus cytoplasm
• It transport material between various region in
  the cytoplasm
• It can be site for some bio chemical activities 
• Ribosomes manufacture protein molecules proteins

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