Exam 4: The Structure and Function of the Plasma Membrane

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.

Which of the following is a function of membranes?

What causes the membrane potential to return to the normal negative value after an action potential has occurred?

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

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

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

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

What kind of membrane protein penetrates into the hydrophobic part of the lipid bilayer?

What complications in the story of the CFTR and its relationship to CF have been introduced by subsequent studies?

How is a nerve impulse usually transmitted across a synapse from a presynaptic to a postsynaptic cell?

Why are the proteins being separated on an SDS polyacrylamide gel attracted equally to the positive electrode?

Enzymes that move certain phospholipids between leaflets have also which of the following properties?

Which of the following cell processes depend on the movement of membrane components and would probably not be possible if membranes were rigid,nonfluid structures?

A channel that opens in response to the binding of a specific molecule,which is usually not the solute that passes through the channel is called a ________.

Why are integral membrane proteins difficult to study?

Glycolipids have been shown to play roles in certain disease states in humans and other mammals.Which of the situations below illustrate the ways in which this can happen?

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?

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

People with the most severe cases of CF transport no chloride ions,while people with less severe cases transport some Cl- ions.What is a possible explanation of this?

Cocaine acts by _________.