Exam 5: Membrane Transport and Cell Signaling

Figure 5.4 -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.Figure 5.4 illustrates the change in the mass of the bags over time.Which line or lines in the graph in the figure represent(s)bags that contain a solution that is hypertonic at 50 minutes?

Which of the following enzymes adds a phosphate group to target proteins?

When a neuron responds to a particular neurotransmitter by opening gated ion channels,the neurotransmitter is serving as which part of the signal pathway?

Submerging a plant cell in distilled water will result in

Figure 5.5 -Which of the following types of signaling is represented in Figure 5.5?

When biological membranes are frozen and then fractured,they tend to break along the middle of the bilayer.The best explanation for this is that

At human body temperature (37°C),cholesterol in membranes functions to

Cystic fibrosis is a genetic disease in humans in which the CFTR protein,which functions as a chloride ion channel,is missing or nonfunctional in cell membranes.The CFTR protein belongs to what category of membrane proteins?

Which of the following processes includes all the others?

Steroid hormone receptors in animals tend to be

A drug designed to inhibit the response of cells to the steroid hormone aldosterone would almost certainly result in which of the following?

The phosphate transport system in bacteria imports phosphate into the cell against the phosphate concentration gradient.The energy for phosphate import is provided by a pH gradient across the membrane (lower pH outside the cell than inside the cell),rather than by ATP hydrolysis.The bacterial phosphate transport system is an example of

The sugars associated with glycoproteins and glycolipids of animal cell membranes

What kinds of molecules pass through a cell membrane most easily?

Submerging a red blood cell in distilled water will result in

Which of the following molecules are localized on the exterior of a phospholipid bilayer?

Which of the following is a characteristic feature of a carrier protein in a plasma membrane?

The fluid mosaic model of membrane structure suggests that membranes

Theoretically,how might researchers disrupt signal transduction pathways as possible treatments for cancer?

The electrochemical gradient across a membrane would generally be increased by which of the following membrane proteins?