Chapter 3: Cell membrane transport

Transmembrane proteins

many with different structures that also span the membrane

Tonicity

ability of solution to cause a cell to gain or lose water

Cotransport

active transport if a solute indirectly drives transport of another solute

Fluid Mosaic Model

membranes are fluid mosaics of lipids and proteins

Phospholipids

Have hydrophobic and hydrophilic regions

Flippase vs Floppase

moves outer phospholipid leaflet to the inner phospholipid leaflet, and opposite

Unsaturated fatty acid membrane vs saturated fatty acid membrane

unsaturated are more fluid than saturated

Steroid cholesterol

acts as building blocks of the plasma membranes, maintains structural integrity and regulating fluidity of membranes

Peripheral proteins

not embedded in the lipid bilayer at all; they are appendages loosely bound to the surface of the membrane

Proteins in the plasma membranes

determine most of the membranes specific functions

Integral proteins

penetrate hydrophobic core and span the membrane

6 functions of membrane proteins

Transport, enzymatic activity, signal transduction, cell to cell recognition, intercellular joining and attachment to the cytoskeleton and ECM

Passive transport

Requires NO energy, Movement of molecules from high to low concentration, Moves with the concentration gradient

active transport

Energy-requiring process that moves material across a cell membrane against a concentration difference. Primary (uses ADP to ATP) and Secondary (uses that energy)

exocytosis and endocytosis

Transport larger molecules out of and into cell

Diffusion

tendency for molecules to spread out evenly into available space and use concentration gradient

Osmosis

diffusion of water across semi permeable membrane low to high solute conc.

Isotonic solution

Solute conc is the same as inside the cell no water movement

Hypertonic solution

solute conc is greater than inside the cell; cell loses water

Hypotonic solution

solute conc is less than inside the cell, cell gains water

Channel proteins

provides a specific molecule or ion to cross membrane

carrier proteins

undergo a subtle change is shape that translocated the solute binding site across the membrane

Sodium Potassium Pump

2 K in, 3 Na out

Uniport, Symport and antiport

one, two the same way and two opposite ways through a protein channel

Primary and Secondary active transport

Energy is derived directly from ATP, secondary used the electrochemical gradient created by the primary transport

three types of endocytosis

phagocytosis (cell engulfs particle in a vacuole), pinocytosis (cell creates a vesicle around fluid), receptor-mediated endocytosis (binding of ligands to receptors triggers vesicle formation