Chapter 4 and 5

Cell Structure and Function

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

Cell Membrane

Diffusion and Osmosis

Active Transport

Endocytosis and Exocytosis