Cell is the basic unit of life. Discuss in brief.
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→ Cells are the structural and functional unit of life.
* All living organisms are made up of cell. That's why cell is known as structural unit of life.
* A single cell can perform all life functions with the help of it's components. Therefore it is known as functional unit of life.
→ Robert Hooke first discovered the cell in 1665.
* He prepared a thin slice of cork and observed it under self made microscope. He saw some box like structures which he named as cell.
→ Anton Von Leeuwenhoek first saw the living cell and also first describe the living cell.
→ Cells can replicate independently.
→ It contain hereditary information due to presence of nucleus or nucleoid.
→ All organisms are made up of cells. Organisms with single cells are known as unicellular organisms. And organisms with multiple cells are known as multicellular organisms.
→ Cells size ranges from 1 - 100 μm.
→ Mycoplasmas, is the shortest cell (0.3 μm) and ostrich egg and nerve cells are the largest cell.
→ Cells are in different shapes. Their shape vary with their function. They may be cuboid, thread like, disc like etc.
→ Cells are of two types namely; Eukaryotic an Prokayotic cells.
a) Eukaryotic cells :-
* These are generally large in size.
* Nuclear region is well defined and surrounded by a nuclear membrane.
* These are multicellular.
* Single chromosome are present.
* Member bound cell organelles are present such as mitochondria, endoplasmic reticulum, golgi appartus etc.
* DNA is linear.
* Cell divides by binary fission and budding.
* Ex :- Human beings, plants etc.
b) Prokayotic cells :-
* These are smaller in size.
* Nuclear region is not well defined and not surrounded by a nuclear membrane.
* These are unicellular.
* More than one chromosomes are present in it.
* Membrane bound cell organelles are absent such as mitochondria, endoplasmic reticulum, golgi appartus etc.
* DNA is circular.
* Cell divides by mitosis and meiosis.
* Ex :- Bacteria, blue-green algae etc.
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Answer:
This fact was first started by Matthias Schleiden and Theodor Schwann and forms the basis of the cell theory. It is considered to be the smallest and basic unit of life that supports all life processes that are important for survival. All the metabolic processes of an organism takes place inside a cell.
Organisms can be formed of either one cell or multiple cells. Examples of single cellular organisms are Amoeba, Paramecium, etc.
Examples of multicellular organisms are plants and animals.
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