Cell Membrane Transport 2 Flashcards
Name 3 characteristics of active transport.
- non spontaneous
- requires energy (movement is uphill)
- involves a “pump” (membrane protein)
What are the 2 functions of membrane proteins?
- transporter
- enzyme
What are the 4 characteristics of a pump?
- type of membrane protein
- can harness energy
- specific binding sites
- demonstrates saturation
What are the 2 types of active transport?
- primary active transport
- secondary active transport
Where does the energy come from in primary active transport?
- a high energy compound
- usually ATP hydrolysis
What happens in secondary active transport?
- energy is released from ion diffusion
- energy drives a pump
- diffusion results from previous active transport of the ion
Describe the sodium-linked glucose pump.
- secondary active transport of glucose
- diffusion of Na+ provides energy
- pump actively transports glucose
Describe the sodium-linked proton pump.
- secondary active transport of H+
- diffusion of Na+ provides energy
- pump actively transports H+ ions
Why do ICF and ECF concentrations differ?
- active transport
- leaks ions to maintain membrane potential
Define osmosis.
diffusion of water through a membrane
What are the 3 characteristics of osmosis?
- always passive
- unaffected by membrane potentials
- driven by water gradient
What are the 3 types of osmolarity?
- iso-osmotic
- hyperosmotic
- hypo-osmotic
What is osmotic pressure? What does it reflect?
- ability to “pull” water
- reflects total solute concentration
_______ _________ increases, thus osmotic pressure increases.
solute concentration
What is transported within membrane bound compartments?
macromolecules
