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21 Cards in this Set

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What are the two types of movement across membranes discussed in this lecture?
Diffusion through channels and movement through transport proteins.
What we refer to as diffusion actually takes place through what?
Channels.
What types of molecules can diffuse?
Water, gases, and small uncharged polar molecules.
Are channels usually monomeric, usually multimeric, or a mix of both?
Usually multimeric.
What factors can influence the speed of diffusion?
Concentration gradient, the thickness of the bilayer, and the diffusion coefficient (influenced by the solubility, size, and shape of the molecule).
What are the different states of action of a channel?
Open, closed, and inactivated.
What is "rectification" as used to describe a channel?
A preference for movement in one certain direction across the channel.
How many units typically comprise a channel, and what shape do they make?
4 units comprise a channel, and they form a round shape with a pore in the middle.
Describe a ligand gate.
The ligand attaches to the gate (can be from inside or outside of the cell) and causes it to open.
Are transport proteins typically monomeric, typically multimeric, or some of both?
Some of both.
Coupling of solutes takes place in which form of movement, through channels or protein transport?
Protein transport.
Which form of movement is faster, channels or protein transport?
Channels.
Which form of movement can move molecules "uphill," channels or protein transport?
Protein transport.
The plot of the rate of diffusion, with the concentration gradient on the x-axis and rate of transport on the y-axis, is what shape?
Straight line.
The plot of the rate transport proteins, with the substrate concentration on the x-axis and the transport rate on the y-axis, is what shape?
Curvilinear.
What is a uniporter?
A transport protein that only carries one molecule through at a time.
What is a symporter?
A transport protein that carries a molecule through along with a "co-transported ion."
What is an antiporter?
A transport protein that carries a molcule through while simultaneously moving an ion through in the other direction.
The Nernst equation calculates what, and on the basis of what cell conditions?
It calculates the voltage inside the cell, based on the concentrations of potassium inside and outside of the cell.
What is the ratio of ions moved by the sodium-potassium pump?
3 sodium out for every 2 potassium in.
The Gibbs-Donnan Equilibrium of concentration and charge is disrupted by the presence of what charged entities within the cell?
Proteins, which are generally negatively charged.