What are Living Organisms Made Up of?

Tejinder Kaur, Academic Content Creator at Edumarz

Each and every living organism body is composed of cells. It is the smallest unit of life that’s liable for all the life processes. On the basis of number of cells organism is made up of, organisms are classified in two types :

  • Unicellular – When the body of the organism is made up of a single cell. Example: Amoeba

  • Multicellular – When the body of the organism is made up of more than one cells of same or varying types. Example: Animals

The Branch of Biology that deals with the study of cells is called “Cytology”.

Robert Hooke, a physicist in 1665 first of all discovered the cell in a slice of cork with the help of a primitive microscope.

The discovery of the Compound Microscope by Zacharias Jansen, is one of the most significant events in the history of Biological Sciences. Jansen took different sizes and types of lenses and placed them at opposite ends of a tube for the observation of small objects placed under them. Robert Hooke made some improvements in the Jansen’s microscope and observed many objects with it. He took two convex lenses to examine specimens. He tried to examine the same species first using the reflected light and then transmitted light. A clear picture of the specimen was observed under the transmitted light. On observing a section of cork using his microscope he discovered a cell and published his findings in the book “Micrographia”.

Leuwenhoek in 1674 for the first time observed free living cells in the pond water and called them “animalcules”.

Cell Theory:

  • It was proposed by Biologists Schleiden and Schwann.

  • According to this, each and every living organism is made up of cells.

  • Cell is the Structural and Functional unit of life.

  • All the cells arise from pre existing cells (Robert Virchow).

What is the cell made up of?

Every cell when viewed under the microscope consists of three basic parts, the nucleus, cell membrane (plasma membrane) and the cytoplasm. The activities performed by the cell are possible because of these three basic parts.

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