Human Anatomy Chapter 2 Transport Processes Across A Plasma Membrane

Front 1

Simple Diffusion:
(passive)

Back 1

Movement type: Unaided net movement of a substance due to molecular motion down its concentration gradient across selectively permeable membrane; continues until equilibrium is reached.

energy source: molecular movement

ex: exchange of O and CO2 bet blood and body tissues.

Front 2

Passive Transport:

Back 2

Movement of substance ALONG a concentration gradient; ATP NOT required

Front 3

Osmosis:
(passive)

Back 3

Movement type: Diffusion of water across a selectively permeable membrane; direction is determined by relative solute concentrations; continues until equilibrium is reached.

Energy source: Molecular movement

Ex: Water in small kidney tubules moves across a cell barrier back into the blood from the tubulas fluid that eventually forms urine

Front 4

Facilitated Diffusion:
(passive)

Back 4

Movement type: Movement of materials too large to pass through membrane channels; relies on transport proteins.

Energy source: molecular movement requiring carried assistance by a transport protein.

Ex: Transport of glucose into cells

Front 5

Bulk Filtration:
(passive)

Back 5

Movement type: Bulk movement of solvents and solutes from an area of high concentration to an area of low concentration as a result of hydrostatic pressure differences across the membrane.

Energy source:

Ex:

Front 6

Ion Pumps:
(active)

Back 6

Movement type: transport of ions across the membrane against a concentration gradient by transmembrane protein pumps.

Energy source: ATP

Ex: Sodium-potassium pump

Front 7

Bulk Transport:
(active)

Back 7

Movement type: membrane vesicles from around materials for transport

Energy source: ATP

Front 8

Exocytosis:
(active)

Back 8

Movement type: Bulk movement of substances OUT of the cell by fusion of secretory vesicles w/plasma membrane.

Energy source: ATP

Ex: Release of digestive enzymes by pancreatic cells.

Front 9

Endocytosis:
(active)

Back 9

Movement type: Bulk movement of substances INTO a cell by vesicle forming at the plasma membrane

Energy source: ATP

Front 10

Phagocytosis:
(active)

Back 10

Type of endocytosis in which particular materials move into a cell after being engulfed by pseudopodia at the cell surface; vesicles form at the inside of the plasma membrane; large sacs are called vacuoles.

Energy Source: ATP

Ex: white blood cells engulfing a bacterium.

Front 11

Active Transport:

Back 11

Movement of substance AGAINST a concentration gradient; requires ATP; requires assistance to move across the membrane, often by a transport protein and sometimes by bulk movement.

Front 12

Pinocytosis:
(active)

Back 12

Movement type: Type of endocytosis in which plasma membrane folds inward to capture extracellular fluid droplets and its dissolved contents, forming a small new vesicles inside the cell.

Energy source: ATP

Ex: Formation of small vesicles in capillary wall to move fluid and small particulate materials out of the blood.

Front 13

Receptor-mediated Endocytosis:
(active)

Back 13

Movement type: Type of endocytosis in which specific molecule-receptor complexes in the plasma membrane stimulate the clustering of bound molecule-receptor complexes; vesicles containing specific molecules bound to receptors in the membrane stimulate internalization of the bound molecules.

Energy source: ATP

Ex: Uptake of cholesterol into cells.