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Module 1 Lecture 1 Cont. Dr. Fuller Membrane Transport (includes Vodcast 1)

Terms in this set (77)

If a solute needs help to get across the membrane via a transmembrane protein that spans all the way through the lipid bilayer, this type of transport is referred to as _____________. What are the different factors that this depends on?
This is referred to as facilitated diffusion; which is facilitated by integral membrane proteins. The most simple version of this is with proteins that form pores or channels. The figure with the triangles pictures a pore. This depends on the concentration gradient and whether or not the channel is available. This will still use like high concentration to low concentration.
What are the different types of facilitated diffusion?
--There are pores and channels (which are pretty simple and use a transmembrane protein with essentially a hole in it that allows solutes to pass thru it)--triangle diagram
--The 2nd type is carrier mediated facilitated diffusion in which a molecule of solute binds to the transmembrane protein; that protein undergoes a conformational change and then it will release solute on the other side of the membrane. It is still working with the concentration gradient, just using a different mechanism.
What are the different types of transport across cell membranes? Include subtypes
There is Simple Diffusion which is basically when the solute can pass through the membrane without assistance and depends on concentration gradient
Theres Facilitated Diffusion - both this and simple diffusion are types of passive transport
--2 types
Carrier mediated in which a molecule of solute binds to the transmembrane protein; that protein undergoes a conformational change and then it will release solute on the other side of the membrane. It is still working with the concentration gradient, just using a different mechanism.
Pore or Channel in which a transmembrane protein essentially has a hole in it that allows the solute to go down the concentration gradient.
Active Transport - It will move things against the gradient (from low to high) This requires energy from ATP- in which the transporters hydrolyze to allow them to move the solute from regions of low concentration to regions of high concentration
When discussing facilitated diffusion, which term (pores or channels) is used for bacteria? What about animals?
Pores is used for bacteria
channels is used for animals
Which of the following characteristics of a solute does NOT play a role in how it can diffusion used a pore or channel down a concentration gradient?

A) Molecular Weight
B) Molecular Structure (geometry)
C) Size
D) Charge
The answer is A. All of the others play a role in if a solute can use a pore or channel in facilitated diffusion.
T or F. Passage through pores or channels can be in either direction (in or out of a cell) and is very fast relative to pumps like the Na+ K+ pump.
TRUE
How are pores and channels selective?
They are selective for certain solutes based on conditions to traverse the membrane.
Which of the following NEVER have a continuous transmembrane path? Explain why this is.
A) Pores
B) Channels
C) Carriers
The answer is C. Carriers never display a continuous transmembrane path (compared to pores and channels) because solute movement across the membrane requires a cycling of conformation changes of the carrier to allow the binding of a limited number of solutes.
Which of the following is the slowest type of membrane transport?

A) Pores
B) Simple Diffusion
C) Channels
D) Carriers
The answer is D. This is because carriers must undergo many different conformational changes to allow diffusion.
Which type of transport follows micaehlis menten kinetics? How does it do so?
Basically this is with carrier mediated diffusion because these carriers can become saturated and then cannot accept anymore solute. Simply diffusion on the other hand obeys Fick's first law. Where are carrier mediated transporters display competitive inhibition.
What type of transport is glucose uptake by GLUT transporters?
This is carrier mediated facilitated diffusion. This still deals with high to low concentration gradient.
What are the important ions within cells versus plasma? Give these values.
Look at following diagram. Basically the ones in red you need to know.
Na+ is about 140 in plasma and only 9 intracellular
K+ is 3.5-5 in plasma but about 135 in intracellular
Ca2+ is about 1.3 in plasma but 10^-4 in intracellular
HCO3- is 24 in plasma but 9 in ICF
What is the pH in plasma? What about in intracellular compartment?
The pH in plasma (blood) is 7.4 while in ICF (cell) its 7.1-7.2
Every cell has _______ in regards to cell transport
A sodium potassium pump; its one of the most important things in our bodies.
Which cell has a sodium pump?

A) Neuron cells
B) Hepatic cells
C) Blood Cells
D) All Cells
The answer is D
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