Flashcards in Chapter 3.4 Deck (7)
What is Tonicity?
the ability of a solution to affect fluid volume and pressure in a cell .
-depends on concentration and permeability of solute
What are transport proteins?
In the plasma membrane, transport proteins carry solutes from one side of the membrane to the other.
- Saturation: As the solute concentration rises, the rate of transport rises, but only to a point - Transport Maximum (Tm).
2 types of carrier mediated transport:
Facilitated diffusion and active transport
List the types of Membrane Carriers
Uniport - carries only one solute at a time
Symport - carries 2 or more solutes simultaneously in the same direction (contrasport)
Antiport -Carries 2 or more solutes in opposite directions ( counter-transport) . Sodium-potassium pump brings in K+ and removes Na+ from cell
What is Facilitated diffusion?
carrier mediated transport of solute though a membrane down its concentration gradient
-does not consume ATP
-solute attaches to binding site on carrier, carrier changes confirmation, then releases solute on other side of membrane.
What is Active transport?
carrier mediated transport of solute though a membrane up (against) its concentration gradient
-ATP energy consumed to change carrier
-Examples of uses: sodium-potassium pump keeps K+ concentration higher inside the cell
-bring amino acids into cell
-pump Ca2+ out of cell
How does a Sodium-Potassium Pump work?
each pump cycle consumes one ATP and exchanges three Na+ for two K+
keeps the K+ concentration higher and the Na+ concentration lower with in the cell than in ECF
necessary because Na+ and K+ constantly leak though membrane