Exam 7: Membrane Structure and Function

Five dialysis bags, constructed of a type of membrane that is permeable to water and 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 with the highest initial concentration of sucrose?

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. In the U-tube illustrated above, ________.

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

The voltage across a membrane is called the ________.

Which of the following processes includes all the others?

Match the labelled component of the cell membrane in the figure with its description. - Which component in the accompanying figure is a microfilament of the cytoskeleton?

Three lab groups carried out an experiment to identify the concentration of sucrose in six solutions. Each unknown contained one of the following sucrose concentrations: 0.0 M, 0.2 M, 0.4 M, 0.6 M, 0.8 M, and 1.0 M. Cubes of sweet potato (1 cm3) were soaked for 24 hours in each solution and weighed to determine the change in mass. Each data entry represents the average of three sample replicates expressed as percent change in mass following a 24-hour soak in the unknown solutions. Unknown Percent change in mass Percent change in mass Percent change in Graup 1 Group 2 Group 3 A 6.6 7.8 7.5 B 3.1 3.7 2.9 -2.7 -3.5 -2.5 0.7 0.5 1.1 E -11.6 -12.3 -12.6 F -5.2 -6.2 -4.9 Based on the data provided, the intracellular molarity of dissolved solutes in sweet potato cells is approximately ________.

Which of the following types of molecules are hydrophilic and therefore excluded from the hydrophobic portion of the phospholipid bilayer?

Match the labelled component of the cell membrane in the figure with its description. - Which component in the accompanying figure plays a critical role in cell-cell recognition?

According to the fluid mosaic model of cell membranes, phospholipids ________.

Match the labelled component of the cell membrane in the figure with its description. - Which component in the accompanying figure is a protein fibre of the extracellular matrix?

The membranes of winter wheat are able to remain fluid when it is extremely cold by ________.

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. Which of the following will be true when the system illustrated above reaches equilibrium?

A patient was involved a serious accident and lost a large quantity of blood. In an attempt to replenish body fluids, distilled water-equal to the volume of blood lost-is added to the blood directly via one of his veins. What will be the most probable result of this transfusion?

Which of the following statements about diffusion is true?

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. When the system illustrated above reaches equilibrium, the sugar concentrations on both sides of the U-tube will be ________.

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

Which of the following membrane activities requires energy from ATP hydrolysis?

Which of the following statements correctly describes the normal tonicity conditions for typical plant and animal cells? The animal cell is in ________.

Which of the following molecules dramatically increases the rate of diffusion of water across cell membranes?