Question

give the historical development of cell theory.

Answer 1

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◆the cell theory was given by german botanist- matthias schleiden and british zoologist theodore schwann.

◆(1838) schleiden observed plants under microscope and described how they were made of cells.

◆(1839) same was done by schwann but on animal tissue.

•they both gave their hyposthesis that:

◆ cells are the fundamental structural and functional unit of life.
---> which stated that all plants and animals are made of cells and products of cell.

◆in 1855, rudolph virchow added that new cells arise from pre-existing cells.

$this \: theory \: however \\ could \: not \: describe \: -$

◆ viruses which were neither living nor non-living.
◆ how the first cell came into existence.

◆the two points are described as:

•viruses are living as:

$1) \: they \: can \: reproduce. \\ 2) \: they \: have \: their \: own \\ genetic \: material. \\ 3) \: they \: are \: metabolically \: \\ active \: inside \: host.$

•viruses are non living as:

$1) \: they \:can \: be \: crytallised. \\ 2) \: they \: have \: high \: specific \\ gravity. \\ 3) \: they \: are \: metabolically \: \\ inactive \: outside \: host.$

•and lastly the problem how the first cell came into existence was decribed by endosymbiotic theory given by Dr. margulis.

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$good \: life...$