Exam 4: The Structure and Function of the Plasma Membrane

A transport system that moves one solute into the cell and another one out of the cell during a single cycle accompanied by the expenditure of energy through ATP hydrolysis could be called a(n)_______

What technique can clarify the dynamic events that occur as a protein functions by introducing into the protein chemical groups (called nitroxides)that contain an unpaired electron? The properties of these nitroxides are sensitive to the distance that separates them and the unpaired electron produces a characteristic spectrum that can be monitored by the technique in question.The technique yields information about the distance between selected protein residues.

What is caused by the inability of Na+ ion channels to open for several milliseconds after their inactivation?

What is thought to be important in maintaining the native structure of the Kv channel membrane protein and promoting its function as a voltage-gated channel.

You are the biologist on an interstellar spacecraft and discover a life form.It appears similar to life forms on Earth.You extract a number of molecules from the organism and characterize them.From the described properties,what kind of molecules are they likely to be and where are they likely to be found? A.an amphipathic molecule that has two long hydrocarbon chains and a polar oligosaccharide head group. B.another amphipathic molecule with two hydrocarbon chains and a phosphate-containing head group. C.a polymer made of amino acids with hydrophobic amino acids on its outer surface in the middle of the molecule and hydrophilic amino acids on its outer surface on each end of the molecule.

A rat cell and a chimpanzee cell are fused together.Antibodies to chimpanzee membrane antigens are labeled with rhodamine (a red fluorescent molecule)and antibodies against rat antigens are labeled with fluorescein (a green fluorescent molecule).What do the cells look like immediately after fusion? What about 40 minutes later? If the temperature of the cell is increased,what should happen?

How do Na+ ions enter a neuron when an action potential is initiated?

The ability,possessed by all organisms,to respond to external stimulation is known as _______.

On average,how many amino acids engaged in predominantly hydrophobic $\alpha$ - helices does it take to cross the hydrophobic part of the membrane?

You modify the gene for an integral membrane protein so that the cytoplasmic portions of the protein are deleted.When the gene is inserted in cells,what happens to the mobility of this protein in the membrane?

In the figure below,why is the stealth liposome coated with polyethylene glycol? What directs the stealth liposome to its target body tissue? Where are lipid-soluble drugs and water-soluble drugs found in stealth liposomes?

In the Na+/glucose cotransporter,_____ moving down its gradient drives the transport of _____ against its gradient.

Impulse propagation by a myelinated axon is called ________ conduction.

Where cells are the most affected by CF? Describe two potential treatments for these symptoms.What are the advantages and disadvantages of lipid-based delivery of the normal CFTR gene?

What word below characterizes the amino acids that are found in an $\alpha$ -helical segment that spans a membrane?

You are studying a transport molecule.It appears to bind temporarily to the molecule to be transported.During normal transport,no energy is expended.The addition of a particular molecule that closely resembles the normally transported molecule inhibits transport.An increase in the concentration of the normally transported molecule in the presence of a constant concentration of the inhibitor increases the rate of transport.What kind of transport is described and what is the inhibiting molecule?

How was it proved that the cystic fibrosis transmembrane conductance regulator (CFTR)was actually a chloride transporter?

In the figure below,what color should the fused mouse and human cell be 40 minutes after the fusion has occurred?

_________ is the movement of a substance from an area of high concentration to an area of lower concentration.

An important aspect of transport by facilitated transporters and pumps is ________.