BY 30 – Fall 2001

LECTURE 6: Membrane Transport

Study Outline Answers

6.1. Membrane Permeability

a. permeable; impermeable

b. semi-permeable

c. nonpolar; hydrophobic; O₂; CO₂; most lipids; H₂O

d. polar; membrane channels; transporters; selective; gated

e. active; ATP; mediated

6.2. Diffusion

a. passive; random thermal

b. concentration gradient; equal; 0

c. the size of the concentration gradient; an increase in temperature; a decrease in the size of the particles; an increase in the surface area for diffusion; distance

d. nonpolar (hydrophobic); polar (hydrophilic); membrane channels; transporters

e. ion channels; gated; Na⁺; K⁺; Cl^-; Ca²⁺

f. osmosis; concentration gradient

g. osmotic; number; osmolarity

h. mOsm (=milliosmoles/L); 100 mOsm; 200 mOsm

i. lower

j. 300 mOsm; < 300 mOsm; iso-osmotic; hyper-osmotic

k. tonicity; impermeant; hypertonic; > 300 mOsm; hypotonic; < 300 mOsm; isotonic; 300 mOsm; impermeant

l. facilitated diffusion; concentration gradient; saturated; equals

m. glucose

6.3. Active Transport

a. energy expenditure; against

b. primary; secondary

c. primary; ATPase; ATP; conformational

d. Na⁺/K⁺ ATPase; 3; 2; Na⁺; out of; K⁺; into

e. Ca²⁺ ATPase; H⁺ ATPase; H⁺-K⁺ ATPase

f. secondary; Na⁺; H⁺

g. against; symporter; amino acids

h. antiporter; Na⁺/Ca²⁺ exchanger; Na⁺/H⁺ exchanger

6.4. Vesicular Transport

a. Vesicles; ATP

b. endocytosis; ligand; receptor-mediated

c. receptors; clathrin; endosomes; membrane; lysosome; Golgi apparatus

d. transferrin; low density lipoproteins (LDLs)

e. Phagocytosis; lysosomes

f. Pinocytosis; receptors

g. exocytosis; waste products; protein