Principle
Cell Theory
All living organisms are composed of one or more cells, the cell is the basic unit of life, and all cells arise from pre-existing cells.
Cell Biology
Field: Cell Biology
Sequence of Expressions
As a cell increases in size, its volume grows faster than its surface area, limiting the rate at which substances can diffuse into and out of the cell.
Principle
Endosymbiotic Theory
Mitochondria and plastids (e.g., chloroplasts) originated as prokaryotic cells engulfed by an ancestral eukaryotic cell.
Principle
Sliding Filament Theory
Muscle contraction occurs because myosin filaments pull actin filaments closer together and thus shorten sarcomeres within a fiber.
Principle
Hayflick Limit
The number of times a normal human cell population will divide before cell division stops.
Principle
Fluid Mosaic Model
The cell membrane is a two-dimensional liquid that restricts the lateral diffusion of membrane components.
Principle
Omnis cellula e cellula
Every cell originates from another existing cell like it.