Cell ( science)

Hey guys !

Today image is about a cell 

okay lets see ;

Disclimer : These all images and notes are all made by me !

                                                                 Cell

Introduction 

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• The cell 
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• You have seen that buildings are made of bricks. Similarly, the bodies of living organisms are made of tiny units cells. Cells can be seen only under the microscope. some organisms are made of only one cell. The cell is enclosed by a thin outer boundary ,called the cell membrane . Most cell have a distinct, centrally located spherical structure called the nucleus . The Nucleus is surrounded by a jelly-like substance called cytoplasm .
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• Note ( Main points)
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• (1) Living organisms are made of tiny units cells.
• (2)The cell is enclosed by a thin outer boundary ,called the cell membrane .
• (3)Centrally located spherical structure in the called the nucleus .
• (4)The Nucleus is surrounded by a jelly-like substance called cytoplasm .
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• Think about it 
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• Everything ( living and non-living ) is made of tinier blocks i,e. atoms and molecules.
• All living organisms carry certain basic functions e.g. respiration, nutrients, excretion,etc.
• Have you wounded what is the smallest level of organistion for living organisms 

• The cell
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• The basis structural unit of all living things. 
• First discovered in 1665 by Robert Hooke.
• Observed in slice of cork and looked like walled compartments under microscope Hence the name "Cell"
• The biggest cell in world  is the egg of Ostrich the size is 170 mm to 130 mm.
• The smallest cell in world is 0.1 to 0.5 Micrometer in bacteria . 
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(3) 

Organisms can be uni-cellular or multi-cellular.

Multi-cellular organisms have verity of cells.

Egg,is a single cell visible to unaided eye.

Study of living cells require staining and observing it under microscope. 

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Cell of Moss leaf  

Cell of Oak steam

 

Human red blood cell

Diversity of life

Cells are classified into two types of cell :-

            'Multicellular organisms'.

            'Unicellular organisms' .

        An organism with billions of cells begains life as a single cell which is an fertilized egg (Zygote).

Unicellular Organisms 

            Organisms made up of only one cell is called 'Unicellular organisms' .

                ( 'Uni means One ; 'Cellular' means cell )

    e.g: Bacteria ,fungi,protozoa,amoeba ,egg and etc.....

            Perform all biological functions on a cellular level itself .

Multicellular organisms 

Organisms made up of more than one cell is called 'Multicellular organisms'.

                ( 'Multi' means Many ; 'Cellular' means cell )

    e.g: Animals,Humans,birds,Plants and ect.....

            Multicellular organisms divided further form a complex body Structure.

            They proceed specialized tissues and organs system to perform various body functions.

Notes:

    (1).  A fundamental structural and functional unit of living organism.

(2). Robert Hoke discovered dead cell in 1665 by looking at slices of cork under a simple magnifying device.

    (3). Organisms made of more than one cell are called Multicellular .

    (4). Organisms made of only one cell are called Unicellular.

Shape of cell

    Amoeba:

                   Do not have a well defined shape.

                   It is irregular in shape and keeps on changing.

                   Pseudopodia (False feet) are projections protecting out of its body.

                   These projections appear and disappear.

                                                                                                 

WBC:

                   Human white blood cells (WBC) also have the abality to change shape.

                   Unable of independent existence. 

Q. Why does the WBC changes its shape ?

Ans.  WBC protect the body against infection.

         Must be able to move anywhere, through blood vessels and infected tissues.

         WBCs destroy microbes by "eating" them.

         These are only possible due to their ability to change shape.

Shape of cells in multicellular organisms

        Multi-cellular organisms have billions of cell in their body.

        They come in all shapes , sizes and numbers.

                                                        Did you know ?

 It is difficult to say the exact number of cells in the human body.

 The number varies from 5 billion to 200 million trillion cells !

 By simple math , the weight of a cell is ~1 nano-gram , for a person weighting 70 kg . This comes out to approximately 70 trillion cells !

        Dependent  on the function .

        could be spindle Shaped e.g. muscle cell.

        Generally round spherical or elongated .

        Branched e.g. Neuron,useful for transferring and receiving message.

                                                                               

Cell Membrane

Enclose components of the cell.

Gives shape to the animal and plant cell.

Plant cells have an additional layer , the cell wall.

Also present in bacteria .

Provides shape and rigidity.

Size of cell

Cells of various sizes can be found in living organisms.

Rather,it depends upon the function of the cell.

The size does not depends upon the sizes of the organisms.

For instants , neurons in both elephants and rats are long and branched.

The smallest cell is 0.1 to 0.5 micrometer, in Bacteria.

The largest cell is the Ostrich egg, measuring 170 mm*130 mm .

An egg is a single cell.

Upon boiling an egg we see a white material surrounding a yellow sphare.

The white material is Albumin.

Wheres the yellow sphere is called Yolk.

Most cells are microscope and can only be seen with the aid of powerful 

microscope. however, some cells are as large a few centimeter.

Ovum,the female games is the largest human cell ~0.12 mm .

In biological studies ,we study object too small to be studied through the eye.

for example, the smallest known living organism.

Nunoarcheum equitans  is 400 mm in diameter , for reference 1 nanometer is 1/10000000th of 1 millimeter.

Groping of cells 

Cell , fundamental unit of life for every living organisms.

tissue, a group of similar cell organised for a specific function .

Organs, group of tissues organised for a biological function.

Organisms.