Chapter 04: Transport of Substances Through Cell Membranes

Chapter 04: Transport of Substances Through Cell Membranes

Complete Chapter Questions With Answers

Sample Questions Are Posted Below

1. An artificial membrane is created consisting of a lipid bilayer without protein molecules in the membrane. The lipid composition of the membrane is essentially the same as that of a normal, biological membrane. Which of the following substances permeates the membrane more readily than water molecules?
   1. Carbon Dioxide
   2. Glucose
   3. Glycerol
   4. Sodium
   5. Urea

ANS: A

2. A cell is equilibrated in an aqueous solution of 300 mOsm/L sodium chloride. Which of the following best describes what will happen to cell volume when the cell is placed in an aqueous solution of 300 mOsm/L calcium chloride?

1. Decrease
2. Decrease and then increase
3. Increase
4. Increase and then decrease
5. No change

ANS: E

3. The intracellular calcium ion concentration of ventricular muscle cells averages 10^-4 mmol/L during diastole. The calcium ion concentration in transverse tubules (T-tubules) averages 2.5 mmol/L at rest. A protein transporter on the membrane of the T-tubule exchanges sodium for calcium. The transporter uses the transmembrane sodium gradient to fuel the exchange. Which of the following transport mechanisms best describes this type of transporter?

1. Facilitated diffusion
2. Primary active transport
3. Secondary active co-transport
4. Secondary active counter-transport
5. Simple diffusion

ANS: D

4. Human red blood cells (RBCs) and rabbit RBCs are equilibrated in separate solutions of isotonic saline (300 mOsm/L NaCl). The human RBCs are then placed in a solution of 300 mOsm/L glycerol, which causes them to swell and burst. However, rabbit RBCs placed in 300 mOsm/L glycerol neither swell nor shrink. Based on this information, which of the following can be concluded about a 300 mOsm/L solution of glycerol for the different cell types?

Human RBCs                                                              Rabbit RBCs

1. Hypertonic and hyperosmotic Hypotonic and hypoosmotic
2. Hypotonic and hypoosmotic Hypertonic and hyperosmotic
3. Hypotonic and isoosmotic Isotonic and isoosmotic
4. Isotonic and hypoosmotic Isotonic and hyperosmotic
5. Isotonic and isoosmotic Hypotonic and isoosmotic
6. Isotonic and hyperosmotic Isotonic and isoosmotic

ANS: C