Exam 7: Membrane Structure and Function

Five dialysis bags, constructed from a semipermeable membrane that is impermeable to sucrose, were filled with various concentrations of sucrose and then placed in separate beakers containing an initial concentration of 0.6 M sucrose solution. At 10-minute intervals, the bags were massed (weighed) and the percent change in mass of each bag was graphed. -Which line in the graph represents the bag that contained a solution isotonic to the 0.6 M solution at the beginning of the experiment?

The sodium-potassium pump in animal cells requires cytoplasmic ATP to pump ions across the plasma membrane. When the proteins of the pump are first synthesized in the rough ER, what side of the ER membrane will the ATP binding site be on?

An organism with a cell wall would most likely be unable to take in materials through

Which of the following statements correctly describes the normal tonicity conditions for typical plant and animal cells?

A protein that spans the phospholipid bilayer one or more times is

For the following questions, match the labeled component of the cell membrane in the figure with its description. -Which component is the peripheral protein?

The presence of cholesterol in the plasma membranes of some animals

-Based on the figure above, which of these experimental treatments would increase the rate of sucrose transport into the cell?

The solutions in the two arms of this U-tube are separated by a membrane that is permeable to water and glucose but not to sucrose. Side A is half-filled with a solution of 2 M sucrose and 1 M glucose. Side B is half-filled with 1 M sucrose and 2 M glucose. Initially, the liquid levels on both sides are equal. -After the system reaches equilibrium, what changes are observed?

The solutions in the arms of a U-tube are separated at the bottom of the tube by a selectively permeable membrane. The membrane is permeable to sodium chloride but not to glucose. Side A is filled with a solution of 0.4 M glucose and 0.5 M sodium chloride (NaCl), and side B is filled with a solution containing 0.8 M glucose and 0.4 M sodium chloride. Initially, the volume in both arms is the same. Refer to the figure to answer the following questions. -If you examine side A after three days, you should find

For the following questions, match the labeled component of the cell membrane in the figure with its description. -Which component is a microfilament of the cytoskeleton?

Some regions of the plasma membrane, called lipid rafts, have a higher concentration of cholesterol molecules. As a result, these lipid rafts

In receptor-mediated endocytosis, receptor molecules initially project to the outside of the cell. Where do they end up after endocytosis?

In the years since the proposal of the fluid mosaic model of the cell membrane, which of the following observations has been added to the model?

Cell membranes are asymmetrical. Which of the following is the most likely explanation?

The phosphate transport system in bacteria imports phosphate into the cell even when the concentration of phosphate outside the cell is much lower than the cytoplasmic phosphate concentration. Phosphate import depends on a pH gradient across the membrane-more acidic outside the cell than inside the cell. Phosphate transport is an example of

Which of the following is true of integral membrane proteins?

Which of the following is a reasonable explanation for why unsaturated fatty acids help keep any membrane more fluid at lower temperatures?

For the following questions, match the labeled component of the cell membrane in the figure with its description. -Which component is cholesterol?

Which of the following is most likely true of a protein that cotransports glucose and sodium ions into the intestinal cells of an animal?