04.3I BIO Active Transport (PART I)

Active Transport (Definition)

The movement of materials from an area of low concentrations to high concentration LOW → HIGH; a carrier transport protein and energy (ATP) are required OR bulk transport where vesicles are formed; includes proton/ion pumps, endocytosis and exocytosis

Active Transport (Types)

Proton/Ion Pumps

Endocytosis

Exocytosis

Active Transport (Materials Transported)

Large polar molecules

Some Ions (H+, Na+, K+, Ca+2)

Hormones

Enzymes/Proteins

Food/Wastes

Carrier Protein

A type of transport protein that spans the membrane, contains 2 active sites, a recognition site and an ATP binding site

Ion pump

A carrier protein that uses cellular energy to "pump" ions such as H+, Na+, K+, Ca+2 across the membrane

Proton Pump

A specific type of ion pump that uses cellular energy to "pump" hydrogen ions (H+) against concentration gradient (from low to high concentration)

Sodium-Potassium Pump

A carrier protein that actively transports sodium ions (Na+) and potassium ions (K+) against their concentration gradients; ATP is required to change the shape of the carrier protein; three Na+ are pumped out of the cell and two K+ are pumped into the cell

Endocytosis (Definition)

Bulk transport of materials INTO the cell through the formation of a vesicle; energy is required (ATP); includes phagocytosis and pinocytosis

Endocytosis (Types)

Types include:

- Pinocytosis - "drinking"

- Phagocytosis - "eating"

Endocytosis (Materials Transported)

Responsible for the transport of large proteins or microorganisms; i.e. amoeba engulfing paramecium, WBC destroying bacteria

Phagocytosis

A type of endocytosis in which SOLID materials are engulfed and brought into the cell

Pinocytosis

A type of endocytosis in which LIQUID materials are engulfed and brought into the cell

Exocytosis (Definition)

Bulk transport of materials OUT of cell through the formation of a vesicle; energy is required (ATP)

Exocytosis (Materials Transported)

Responsible for the transport of:

- Large molecules

- Enzymes/proteins

- Hormones (proteins or lipids)

- Wastes