Exercise 5A The Cell: Transport and Membrane Permeability
There are two general categories of cellular transport mechanisms:
Passive Simple diffusion Facilitated or protein mediated Filtration Osmosis Active ATP driven solute pumps Vesicular Endocytosis Phagocytosis Bulk-phase endocytocysis (pinocytosis) Phagocytosis Types of transport
Rate of diffusion is influenced by: concentration temperature molecular or atomic weight of solute density of solvent gases allow for the quickest liquids are intermediate solids allow for the slowest
Diffusion
Diffusion of dye in agar KMnO 2 Methylene blue
Facilitated diffusion
Osmosis a.
Osmosis b.
What’s an “Osmometer”?
Normal erythrocytes in an isotonic solution
RBCs in hypertonic saline solution: crenation
Isotonic vs hypotonic Normal RBCs: 0.9% NaCl Hemolysis: Distilled water
Active transport requires cellular energy
Exocytosis
Endocytosis (a.k.a. pinocytosis)
Phagocytosis: cellular eating
Active transport: Antiport The sodium/potassium pump
Active transport: Symport The sodium/glucose symporter
Transport Animations