Exam 6: Lipids, membranes, and the First Cells

You have just discovered an organism that lives in extremely cold environments.Which of the following would you predict to be true about the phospholipids in its membranes,compared to phospholipids in the membranes of organisms that live in warmer environments?

In an experiment involving planar bilayers,a solution of table salt (sodium and chloride ions in water)is added on the left side of the membrane,while pure water is added on the right side.After 30 minutes,the researchers test for the presence of ions on each side of the membrane.The right side tests negative for ions.What can you conclude?

You want to view the surface of a particular cell or tissue (group of related cells)at magnifications above 1000x.What tool would you use?

Which characteristic would be expected in the plasma membranes of a plant that can survive winters in Northern Ontario,compared to a plant growing in a warmer region?

Cooking oil and gasoline (a hydrocarbon)are not amphipathic molecules.Why?

Which of the following is the best explanation for why vegetable oil is a liquid at room temperature,while animal fats are solid?

Under what circumstances does membrane transport always require energy?

The term phospholipid can best be described by which of the following?

What is the name of the currently accepted model of membrane structure,and where does it place membrane proteins?

What will happen to a red blood cell (rbc),which has an internal ion concentration of about 0.9 percent,if it is placed into a beaker of pure water?

Which aspect of phospholipids is most important to the formation of bilayers?

Cystic fibrosis (CF)is a membrane-transport disease that is caused by an allele found primarily in Caucasian populations.What mechanism fails in CF patients?

You have a planar bilayer at a relatively warm temperature.After testing the permeability of this membrane to glucose,you increase the quantity of cholesterol in the bilayer.What will happen?

Which of the following substances would most likely require a protein to facilitate its diffusion across a cell membrane?

Sodium-potassium pumps

Steroids are

What type of functional group results when the alcohol group on glycerol reacts with the carboxylic acid group on a fatty acid?

Which of the following crosses lipid bilayers the slowest?

Suppose some blood cells were in an isotonic solution.What would happen to them?

Phospholipid bilayer membranes are selectively permeable.What does that mean?