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Discovery Of Cell Organelles

CBSE ADDA
Discovery of nucleus:
  When Robert Hooke observe the cell structure of the cork, he didn't pay attention to the small particles. He didn't know anything about nucleus and cytoplasm. Until 1774's some one discovered that the cell of stonewort  has some liquid floating inside the cell. 50 years later, Brown discovered that there was gummosis inside the cell moving randomly.  Later, he called this kind of movement the Brownian Motion. In 1833s, Brown discovered nucleus in cells.  
Discovery of chloroplast:                                      
  P.J.Pelletier (1788-1842) cooperated with J.B. Caventou, they named the green substance chlorophyll in 1818s.Untill 1864,we already knew chlorophyll was combined by two yellow and two green pigments. Andreas Franz Wihelm Schimper18561901first used chloroplast in 1885s to discovered that chloroplast was a combination of stroma and grana. 
Discovery of endoplasmic reticulum: 
 In 1945s, Porter used electron microscope to observe the movement of cell. He discovered the whole cytoplasm have some structure like net. Later, he named the structure endoplasmic reticulum and sure that it as a new cell organelle.
Discovery of mitochondrion: 
After the discovery of ribosome, many scientists announced some important reports about cells. But the most important thing is that someone found a particle which looked like a small flagella in the muscle cell  structure. Many scientists continuously  carried out observations, finally, a German scientist used the principle of chromosome to discover it's mystery and named it mitochondrion

Discovery of Golgi body:                                
  After the discovery of mitochondrion, a scientist called  Camillo Golgi discovered another organelle in the cell, because it was a big discovery in science, so people renamed the cell organelle Golgi body
Discovery of Ribosome:                            
  The relationships between ergastoplasm  and microsomes(微粒). Palade and Siekevitz used centrifugal force to separate, observe their small structure enable to set up. The diameter of a microsomes is 800-200nm accurately. Its surface accretes a lot of grumoses that have a diameter of 15-20nm. If we used centrifugal force to centrifuge them, the grumoses e gained as called Ribosome. Because of this discovery and the use of electron microscope, the technology of centrifuge cell gives excitation to the discovery of cells.
Discovery of cell membrane:                          
  After the 19th century, scientists had make many breakthrough in study cell organelle. In 19th century, a British scientist discovered cell membrane in some plant cell.


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