GENERAL HISTOLOGY

Detailed explanation-1: -The classical cell theory was proposed by Theodor Schwann in 1839. There are three parts to this theory. The first part states that all organisms are made of cells. The second part states that cells are the basic units of life.

Detailed explanation-2: -The cell theory states that all biological organisms are composed of cells; cells are the unit of life and all life come from preexisting life. The cell theory is so established today that it forms one of the unifying principles of biology.

Detailed explanation-3: -Virchow’s theory stated that just as animals are unable to arise without previously existing animals, cells are unable to arise without previously existing cells. The idea that new cells arose from pre-existing cells in both diseased and healthy tissue was not original.

Detailed explanation-4: -1) All organisms are made of cells. 2) All existing cells are produced by other living cells. 2) All existing cells are produced by other living cells. 3) The cell is the most basic unit of life.

Detailed explanation-5: -Prokaryotes. Prokaryotes are generally small cells that are enclosed by the plasma membrane. Eukaryotes. Eukaryotic cells have a nucleus, organelles, and a plasma membrane surrounding them. Single-celled Organisms. Cell theory can be well understood by looking at single-celled species. Plants. Animals.