Microscope and Cell Discovery

Study Notes

The microscope's invention was pivotal for cell discovery.
Robert Hooke, an English physicist, first described cells in 1665 through observations of cork using his self-built microscope.
The term "cellulae" from Latin means small rooms, which Hooke used to describe the structures he observed.
Antoine van Leeuwenhoek, a Dutch scientist, discovered the first living cells in 1676, referring to them as "Animalcules," earning the title Father of Microbiology.

Matthias Schleiden, a German botanist, concluded in 1838 that all plants consist of individual cells.
Theodor Schwann, in 1839, reported that all animals are also made of cells.
Rudolf Virchow, in 1855, posited that all cells arise from pre-existing cells.
Cell Theory, established through the work of Schleiden, Schwann, and Virchow, includes:
- The cell is the basic unit of life.
- All organisms consist of one or more cells.
- All cells arise from pre-existing cells.

Prokaryotic Cells:
- Lack a nucleus and membrane-bound organelles.
- Typically unicellular, found in Domains Archaea and Bacteria.
- Contain a single, circular chromosome in a nucleoid region (irregular area of DNA).
Eukaryotic Cells:
- Contain a membrane-bound nucleus and organelles, each with specific functions.

Plasma Membrane: Outer layer separating cell's interior from the environment.
Cytoplasm: Jelly-like substance including cytosol and cellular structures; in eukaryotes, it's the region between the nucleus and membrane.
DNA: Genetic material governing cell function and reproduction.
Ribosomes: Protein synthesis machinery of the cell.

Proposes that symbiotic relationships led to the evolution of eukaryotic cells, where one cell engulfs another benefiting both organisms.