Term | Definition |
Simple Diffusion | Molecules or ions move from regions of high concentration to low concentration. |
Simple Diffusion Example: | Exchange of oxygen and carbon dioxide in the lungs |
Facilitated Diffusion | Molecules move across membrane through channels or by carrier molecules for a high concentration to low concentration |
Osmosis | Water molecules move from higher concentration to low concentration through a selectively permeable membrane |
Filtration | Smaller molecules are forced through porous membranes from higher pressure to lower pressure |
Facilitated Diffusion Example: | Movement of glucose through a cell membrane |
Osmosis Example: | Distilled water entering a cell |
Filtration Example: | Molecules leaving blood capillaries |
Active Transport | Carrier molecules transport molecules or ions through membranes from regions of low concentration to high concentration |
Pinocytosis (Endocytosis) | Membrane engulfs droplets of liquid from surroundings |
Phagocytosis (Endocytosis) | Membrane engulfs solid particles from surroundings |
Receptor- Mediated (Endocytosis) | Membrane engulfs selected molecules combined with receptor proteins |
Exocytosis | Vesicles fuse with membrane and release contents outside of the cell |
Transcytosis | Combines receptor- mediated endocytosis and exocytosis to ferry particles through a cell |
Active Transport Example: | Movement of various ions and amino acids through membranes |
Pinocytosis Example: | Membrane- forming vesicles containing large particles dissolved in water |
Phagocytosis Example: | White blood cell membrane engulfing bacterial cell |
Receptor- Mediated Example: | Cell removing cholesterol- containing LDL particles from its surroundings |
Exocytosis Example: | Protein secretion, neurotransmitter release |
Transcytosis Example: | HIV crossing a cell layer |