Unit 3: Cells

Cell Transport

The Goalof cell transport

Homeostasis Stable internal conditions*

* Such as temperature and water

Passive Transport

Definition• Movement across a cell

membrane with NO energy• Goes from high to low

concentration

Types of Passive Transport• Diffusion• Osmosis• Facilitated channels• Ion channels

Passive Transport: Diffusion

Definition• Movement from an high

concentration to an area of low concentration

Passive Transport: Osmosis

Definition• Process of WATER moving

from high to low concentration

• Hypotonic osmosis: water moves INTO the cell

and it swells.

• Hypertonic osmosis: water moves OUT off a cell.

• The cell shrinks.

Isotonic osmosis: solution and cell are both at homeostasis.

Passive Transport: Facilitated Diffusion

Definition• Diffusion with the help of a

busser protein

Busser protein

• Passageway in a membrane for ions* to pass through

• Ion = any atom with a charge (+ or -)

• Example: sodium (Na + or potassium K+)

Passive Transport: Ion Channel

Definition

Active Transport

Definition• Substances moving across

the cell membrane with energy

• Goes from low to high concentration

Types of Active Transport• Cell membrane pump• Endocytosis• Exocytosis

Active Transport: Cell-Membrane Pump

Definition• Bussers pump molecules

across the membrane from LOW to HIGH

Active Transport: Endocytosis

• Definition• The process in which

cells ingest (take in) molecules

• 2 types• Pinocytosis – cells

take in liquids • Endocytosis – cells

take in solids

Active Transport: ExocytosisDefinition

• Cells expel (get rid of) molecules