Exam 4: The Structure and Function of the Plasma Membrane

What did Davson and Danielli add to their model of enzyme structure to explain the passage of polar solutes and ions through the membrane and to account for their selective permeability?

Which of the following is a function of membranes?

Why are integral membrane proteins difficult to study?

What directly or indirectly determines the transition temperature?

Which part of a neuron conducts impulses away from the cell body toward the target cell(s)?

Integral membrane proteins have been engineered to lack the portion that normally projects into the extracellular space.When the gene is inserted in cells,what happens to the mobility of this protein in the membrane?

______ trigger fusion of synaptic vesicles with the synaptic membranes of the presynaptic cell.This same stimulus also triggers ________.

How do the cholesterol molecules depicted in the figure below enhance membrane fluidity?

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

How might a liposome be prepared that could potentially be used in the treatment of a tumor whose cells have a protein called tumor cell antigen (TCA)in their membranes? This protein is missing from all normal cells.

A process in liver cells stops when they are exposed to the inhibitor ouabain,which is an inhibitor of the Na+-K+ pump.What do you conclude about the liver cell process?

The CF mutation is present at very high levels within the Caucasian population and is thought to have arisen more than 50,000 years ago to reach its present level.Since an individual homozygous for the recessive mutant allele has such poor health,what could explain this allele rising to such a high level in the population?

Cocaine acts by _________.

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

What technique below is often used to identify transmembrane segments of integral proteins?

In the 1950s,J.D.Robertson reported that any membrane that he observed in the electron microscope looked the same.This led to his proposal of the Unit Membrane model of membrane structure suggesting that all membranes were exactly alike.Why was this model eventually rejected?

Hemolytic anemias are characterized by fragile,abnormally shaped erythrocytes;the disease has been traced to mutations in ________.

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?

What word describes a molecule that contains both hydrophilic and hydrophobic portions?

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