STEM 113: Passive and Active transport

Passive transport

doesn’t require energy to move molecules from a high to low concentration

Active Transport

requires energy (ATP) to move molecules from a low to high concentration; against the concentration gradient; requires transmembrane proteins

Diffusion

movement of small particles across a selectively permeable membrane until equilibrium

Osmosis

movement of water from one place to another

Tonicity

power of diff. kinds of substances to make water move in and out of the cell

Osmolarity

total concentration of all solutes in solution; solute particles per liter of solution

Hypotonic Solution

contains low concentration of solute relative to another solution; water diffuses into cell causing to swell/explode

Hypertonic Solution

contains high concentration of solute relative to another solution; water diffuses out, causing cell to shrivel

Isotonic

contains same concentration of solute as another solution; water diffuses into and out of the cell at the same rate

Facilitated Diffusion

large molecules are guided by proteins that form channels for it to pass through

Bulk transport

Endocytosis and exocytosis is the mechanism by which very large molecules get into and out of the cell

Exocytosis

moves out of the cell by vesicles that fuses with the plasma membrane

Endocytosis

large molecules move materials into the cell

Receptor-mediated Endocytosis

molecules that attach to the receptors and are captured

Pinocytosis

“cell drinking”; takes in dissolved molecules

Phagocytosis

used to engulf large particles into vesicles; “cell eating”