Download STUDY OUTLINE FOR TRANSPORT THROUGH A MEMBRANE

STUDY OUTLINE FOR TRANSPORT THROUGH A MEMBRANE
I.
II.
III.
IV.
Membrane Structure
a. Phospholipid bilayer
b. Proteins embedded
c. Fluid Mosaic Model
Membrane Function
a. Regulates what enters and leaves
b. Maintains homeostasis
c. Partitions eukaryotic cell into compartments
d. Acts as a boundary
e. Selectively permeable
 Different fatty acids
 Different proteins
 Different functions
f. Protein functions (enzymes, transport, receptors, recognition)
g. Cholesterol function
h. What is responsible for different selective permeability in different
membranes?
What can and can’t pass through membrane
a. Polar and ionic can’t (NaCl, glucose, amino acids, water)
b. Nonpolar can (O2, steroids, and CO2)
c. Small can
d. Large can’t (amino acids)
Passive transport
a. No energy required but requires a concentration gradient
b. Moves with or down concentration gradient (area of high concentration to
area of low concentration)
c. Due to random motion of molecules (kinetic energy, Brownian motion)
d. Substances move independently of each other
e. Dynamic equilibrium
f. Three types of passive transport
 Diffusion
i.
O2 and CO2 move completely by diffusion
ii.
No energy required
iii. Requires concentration gradient
iv.
Understand how oxygen and carbon
dioxide move through lungs, circulatory
system, and body cells
 Osmosis
i.
Diffusion of water through a selectively
permeable membrane.
ii.
Hypertonic-Higher concentration of solute
iii. Hypotonic-Lower concentration of solute
iv.
Isotonic-Equal concentration of solute
v.
vi.
vii.

V.
VI.
Facilitated diffusion
i.
ii.
iii.
iv.
v.
All three above compare two solutions-one
inside cell and one outside cell.
Tries to reach equal solute concentration.
Water moves from hypotonic region to
hypertonic region based on total solute
concentration.
No energy required
Requires concentration gradient
Has help from membrane proteins
High to low concentration
Through a membrane
Water Balance between cells is crucial
a. Animal Cells
 Lysis in hypotonic solution
 Shrivel in hypertonic solution
 Normal in isotonic solution (best environment)
b. Plant Cells-Rigid cell makes a difference
 Flacid in isotonic solution
 Plasmolysis in hypertonic solution
 Turgid in hypotonic solution (best environment)
Active Transport
a. Requires energy
b. Often goes against concentration gradient
c. Through a membrane
d. Requires protein
e. Types of active transport
 Exocytosis
 Endocytosis
i.
Phagocytosis
ii. Pinocytosis
iii. Receptor mediated