Biological Membranes

Membranes

Membrane Proteins Transport Recognition Channels Pumps E- Transfer Antigens, glycoproteins

Membrane Proteins Structural Proteins Receptors Joining Proteins Attachment Receptors Signal Transduction Joining Proteins Enzymatic

Movement Across Membranes Simple Diffusion Random Movement of Molecules Passive transport Concentration Gradients

Movement Across Membranes Osmosis H2O only! Solute Gradient Hypertonic Hypotonic Isotonic

Osmosis & Cells

Movement Across Membranes Facilitated Diffusion Random Movement of Molecules Passive transport Concentration Gradients Channel Proteins

Movement Across Membranes Active Transport Energy is required … ATP Transport Proteins (pumps) Movement AGAINST a concentration gradient.

Sodium-Potassium Pump

Short Homework: How does “Cotransport” work & where in the body would you find such a phenomenon? Be sure site your source(s)

Endocytosis/Exocytosis Movement of very large molecules. Vesicles form or merge with the cell membrane. Secretion of large amounts of a particular substance.

Endocytosis Sometimes, this is “receptor-mediated” Formation of a vesicle Sometimes, this is “receptor-mediated”

Exocytosis Vesicle already formed

Movement Across Membranes Simple Diffusion Osmosis Facilitated Diffusion (Passive Transport) Active Transport Endocytosis Phagocytosis Pinocytosis Exocytosis