1.4 - Membrane Transport Flashcards
Terms to know
Selective Permeability
A characteristic of the cell membrane by which only substances meeting certain criteria can pass through it unaided
Passive Membrane transport
The movement of substances across the membrane without the expenditure of cellular energy
Active Membrane Transport
The movement of substances across the membrane using energy from adenosine triphosphate (ATP)
Concentration Gradietn
The difference in concentration of a substance across a space
Diffusion
The movement of particles from an area of higher concentration to an area of lower concentration
Simple Diffusion
A form of passive membrane transport in which a substance moves across the membrane down its concentration gradient without the use of a membrane protein
Facilitated Diffusion
A form of passive membrane transport used for substances that cannot cross the lipid bilayer on their own due to their size, charge, and/or polarity and require a transmembrane protein to facilitate their movement down their concentration gradient
Channel Protein
A transmembrane protein that forms a channel through the membrane that allows select materials to pass through along their concentration gradient
Carrier Protein
A transmembrane protein that binds and transports a specific molecule across the membrane
Osmosis
The diffusion of water through a semipermeable membrane down its concentration gradient
Isotonic
A solution that has the same concentration of solutes as another solution
Hypertonic
A solution that has a higher concentration of solutes than another solution
Hypotonic
A solution that has a lower concentration of solutes than another solution
Solute Pump
A form of active membrane transport in which a membrane protein uses ATP to move a solute across the membrane most often against its concentration gradient
Symporter
A transmembrane protein that facilitates secondary active transport where both solutes are moved in the same direction across the membrane
