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