Transport Across Membranes Flashcards
Diffusion - concentration gradients
- move from a region of high to low
- eventually reach equilibrium
Types of membrane transport
Diffusion
Osmosis
Active transport
Vesicle mediated transport
Examples of diffusion in our bodies?
Lungs:02 enters blood, CO2 leaves
Nerve impulses: ions cross membranes to allow impulses to travel
Transpiration: H20 evaporation from leaves
Medical imaging: MRI…
Osmosis?
Diffusion of water
Based on concentration of solutes
Types of solutes don’t matter
Tonicity
Refers to relative concentrations across membrane (isotonic hypotonic, hypertonic)
Passive transport?
No additional energy is required
Active transport?
Needs and input of energy
Facilitated diffusion
Diffusion across a membrane using a specific membrane protein that only allows certain molecules to pass through, concentration gradient supplies the energy
Uniport, symport, antiport
You know the difference
Aquaporins?
Membrane proteins that only transfer water molecules
3 billion molecules per second
Gated channels
Proteins that require the binding of a molecule or atom to open the gate, then transport can take place
Sodium concentration gradient in pump?
Higher on outside, lower on inside
Potassium concentration in pump?
Higher on inside, lower on outside
Type of protein transfer for sodium potassium pump?
Antiport, some in some out
What gets pumped in and out in sodium potassium pump?
3 Na+ ions out and 2 K+ ions in
