Important questions and answers of cells class 9th

What is cell?

Ans-It is the basic structural and functional unit of life.

➡️Its shape is like a honeycomb. 

➡️It is hexagonal structure. 

➡️It is discovered by Robert Hooke in 1665.

➡️Firstly Robert Hooke saw in a thin slice of cork*.

➡️Cells means in latin "little room."

Note:- *Cork - Cork is a substance which is obtained from the bark(वृक्ष की छाल) of a tree.

Cell Theory 

➡️Cell comes from the latin word 'Cellula' which means "a little room".

➡️It is discovered by English scientist, Robert Hooke (1635- 1703).

➡️His book 'Micropraphia' was published in 1665. 

➡️In 1674, Anton von Leeuwenboke(1632 - 1723) is discovered free living cells in pond water for the first time in 1674.

➡️He also discovered sperm and identified the sperm cells of humans, dogs, rabbits, frogs, fish and insects. 

➡️Nucleus (in plant) is discovered by Robert Brown (1787- 1889) in 1831.

➡️He is a Scottish botanist. 

➡️The term Protoplasm* is given by J. E Purkinje(1787 - 1869) in 1839.

➡️He is a Czech animal scientist. 

➡️*Protoplasm is fluid substance present in side the cell. 

➡️In 1866, Haeckel found nucleus is responsible (जिम्मेदार) for storing and transmitting(प्रसारण) heredity(अनुवांशिकता) characters. 

➡️Cell theory is given by J. M. Schleiden(Jakob Matthias Schleiden) and Theodor Schwann. 

➡️All cells arise from pre-existing cells. It is told by R. Virchow in 1855.

➡️He is a German biologist.