What is cell theory?

Dami1ola777

1 month ago

Cell theory is a fundamental principle in biology that explains the roles of cells as the basic and functional unit of life and it states that :
1) The cell is the structural and functional unit of life : The cell is the basic unit of life capable of carring outlife processes such as digestion, respiration, reproduction etc.
2) All cells come from previously existing cells : New cells are formed by divison(meiosis and mitosis) . Cells cannot be reproduced simultaneously from non living cells . Instead, life is continued through the process of cell reproduction.
3) All living organisms are made up of cells : Every living organisms ranging from the simplest to the most complex organism comprises of one or more cells . organisms are classifed into 2 based on the number of cells. they are
i) Unicellular organism : organism with only one cell e.g amoeba, euglena, bacteria etc.
ii) Multicellular organism : organism with 2 or more cells e.g man, hydra,sponges etc.
4) There is no life apart from the life of cells: without cells, every life processes such as respiration, digestion, reproduction etc cannot happen . Therefore, life cannot exist.
SCIENTISTS INVOLVED IN CELL THEORY
1) Matthias Schleiden (1838): Declared that all plants are made of cells.

2)Theodor Schwann (1839): Declared that all animals are made of cells, unifying plants and animals under one principle.

3)Rudolf Virchow (1855): Expanded cell theory by stating “Omnis cellula e cellula”, meaning new cells arise only from existing cells. This directly supports the idea that there is no life apart from the life of cells.