4. Transmembrane Transport Part 2 Flashcards
What is passive transport?
thermodynamically favorable movement of a solute across a membrane that does not require the input of energy
What are the two types of passive transport?
simple diffusion
facilitated diffusion
What is simple diffusion?
diffusion of a solute through a membrane without help from a protein
What is facilitated diffusion?
movement of a solute across a membrane, down a gradient, when the membrane itself is intrinsically impermeable to that solute
What are the two main proteins involved in facilitated diffusion?
channel proteins
carrier proteins
What are the three types of gated channel proteins?
gated channel protein
voltage gated channel
ligand-gated channel
What is a gated-channel protein?
ion channel that opens in response to a specific environmental stimuli
What is a voltage-gated channel?
channel that opens in response to a change in the electrical potential across the membrane
What is a ligand-gated channel?
channel the opens in response to binding a specific molecule
What is the purpose of carrier proteins?
transport molecules through membranes by binding the molecule, undergoing a conformational change, and moving the molecule to the other side of the membrane
What are the three different types of carrier proteins?
uniports
symports
antiports
What is a uniport carrier protein?
carrier protein that transports only one molecule across the membrane at a time
What is a symport carrier protein?
carrier protein that will carry two substances across a membrane in the same direction
What is a antiport carrier protein?
carrier protein that will carry two substances across the membrane in opposite directions
What is a pore?
tube through the membrane that is large and not selective for a specific molecule
