Exam 4: The Structure and Function of the Plasma Membrane

You are investigating the transition temperature of a membrane,the origin of which you do not know.The temperature of transition for this membrane is very sharp,occurring over an extremely narrow range of temperatures.What can you say about the composition of the membrane?

The sodium-potassium pump makes the cell interior more ______ by pumping ____ sodium ions out of the cell for every ____ potassium ions pumped in.

What enzyme was instrumental in the discovery of GPI-anchored proteins? It was found that this enzyme would release certain membrane proteins from a membrane.

When membrane lipids are extracted from cells and used to prepare artificial lipid bilayers,cholesterol and sphingolipids tend to self-assemble into ________ that are more gelated and highly ordered than surrounding regions consisting primarily of _________.

Which proteins move the farthest during SDS-polyacrylamide gel electrophoresis?

Synaptic malfunction or dysfunction may cause which of the following diseases?

_________ can be used to trap integral proteins and drag them through the membrane with a known force,using forces generated by a focused laser beam.This yields information about the presence of membrane barriers.

A membrane's transition temperature is determined and found to stretch over a wide range of temperatures.The membrane also exhibits high stability and a reduced permeability similar to that in most mammals.What membrane component is responsible for these traits and how does it do it?

A new,promising drug in the treatment of cystic fibrosis (CF)and the improvement in the quality of life in CF patients is Bronchitol.What is Bronchitol's overall effect on the patient that allows it to improve their situation? What sugar is a major constituent of Bronchitol? How does Bronchitol cause water to move into the extracellular fluid of the airways after being inhaled? What other kinds of compounds might be used in CF treatment in the future?

Once the structure of one member of a membrane protein family has been determined,researchers can usually apply a strategy called __________ to learn about the structure and activity of other members of the family.For example,solution of the structure of the bacterial potassium channel KcsA provided a lot of data that could be applied to the structure and mechanism of action of the much more complex eukaryotic potassium channels.

In the figure below,the bilayer shown is below the transition temperature and the movement of the molecules is greatly restricted.What words can be used to describe this bilayer?

A molecule normally enters a cell by simple diffusion through the lipid bilayer.What happens if you artificially reverse the molecule's concentration gradient?

Look at the hydropathy plot in the figure below.How many transmembrane domains are indicated for glycophorin A in the plot? What is the approximate position of the stretch of amino acids that spans the membrane?

Where is the neuron cell nucleus located?

A procedure in which the gene for an integral membrane protein is altered in such a way that the spatial relationships between some of the amino acids in the protein can be revealed is called ________.

How might a lack of Cl- transport cause the respiratory tract symptoms of cystic fibrosis (CF),specifically the thickened mucus?

What disease is caused by the disruption of the structure depicted in the figure below?

Usually,optical tweezers drag integral proteins a limited distance before they encounter a barrier that causes their release;upon release,they typically spring backward.What does this suggest?

What are some possible explanations for the tendency of CF patients to develop chronic lung infections?

If you were able to study nerve conduction in vitro and you added ouabain,an inhibitor of the Na+-K+ ATPase,to the system,would you expect to see the conduction of nerve impulses cease immediately?