Cell Theory
• Cell Theory states:– All organisms are made of cells– All existing cells are produced by other living cells– The cell is the most basic unit of life
Contributors to Cell Theory
• Robert Hooke (1665) noticed sliced cork had cells when viewed under a microscope
• Anton van Leeuwenhoek (1674) perfected the microscope and examined pond water
• Matthias Schleiden (1838) was the first to note that plants are made of cells
• Theodor Schwann (1839) concluded that all living things are made of cells
• Rudolf Virchow (1855) proposed that all cells come from other cells
Prokaryotic vs. Eukaryotic
• Prokaryotic cells lack a defined nucleus• Eukaryotic cells have evolved to include
complex structures like mitochondria
Cells are Composed of…
• Cytoplasm – a jellylike substance that contains dissolved macromolecules and other minerals
• Organelles – structures specialized to perform distinct processes inside a cell, such as make energy, process proteins and house DNA
• Cytoskeleton – a network of structural proteins that is constantly changing to meet the need of the cell
Cell Membrane
• Forms a boundary between the cell and the outside environment
• Controls the passage of materials into and out of the cell
• Consists of a double layer of phospholipids interspersed with a variety of other assistive molecules, like transport proteins