Bio CH 7 Mastering Questions

Which of the following would be least likely to diffuse through a plasma membrane without the help of a transport protein? A) A large polar molecule B) A large nonpolar molecule C) Any of the above would easily diffuse through the membrane. D) Dissolved gases such as oxygen or carbon dioxide E) A small nonpolar molecule

A) A large polar molecule

If a red blood cell and a plant cell were placed in seawater, what would happen to the two types of cells? A) Both cells would lose water; the red blood cell would shrivel, and the plant plasma membrane would pull away from the cell wall. B) The red blood cell would burst, and the plant cell would shrink. C) The red blood cell would shrink, and the plant cell would gain water. D) Both cells would gain water by osmosis; the red blood cell would burst, and the plant cell would increase in turgor pressure. E) Seawater is isotonic to both cells, therefore, neither cell will change as there will be no movement of water into or out of the cells.

A) Both cells would lose water; the red blood cell would shrivel, and the plant plasma membrane would pull away from the cell wall.

What function do carbohydrates fulfill in the plasma membrane? A) Cell-to-cell recognition B) They contribute to its selective permeability. C) Transport of molecules across the membrane D) They facilitate enzymatic processes. E) They contribute to its "fluid" characteristic.

A) Cell-to-cell recognition

Which of the following statements about diffusion is true? A) It is a passive process. B) It always requires integral proteins of the cell membrane. C) It requires expenditure of energy by the cell. D) It occurs when molecules move from a region of lower concentration to a region of higher concentration. E) It is very rapid over long distances.

A) It is a passive process.

Which of the following statements about passive transport is correct? A) Passive transport permits the solute to move in either direction, but the net movement of the population of solute molecules occurs down the concentration gradient of the molecule. B) Passive transport operates independently of the concentrations of the moving solute. C) Passive transport does not occur in the human body. D) In passive transport, solute movement stops when the solute concentration is the same on both sides of the membrane. E) Passive transport operates independently of diffusion.

A) Passive transport permits the solute to move in either direction, but the net movement of the population of solute molecules occurs down the concentration gradient of the molecule.

Which of the following statements about the role of phospholipids in the structure and function of biological membranes is correct? A) Phospholipids form a selectively permeable structure. B) Phospholipids form a single sheet in water. C) Phospholipids are completely insoluble in water. D) Phospholipids form a structure in which the hydrophobic portion faces outward. E) They are triacylglycerols, which are commonly available in foods.

A) Phospholipids form a selectively permeable structure.

Which of the following cell structures exhibits selective permeability between a cell and its external environment? A) Plasma membrane B) Chloroplasts C) Lysosomes D) Endoplasmic E) Mitochondria

A) Plasma membrane

How does the "fluid mosaic model" describe the structure of the plasma membrane? A) Proteins in the membrane contribute to the mosaic quality of the membrane while the lateral and rotational movements of phospholipids contribute to its fluidity. B) The plasma membrane is a rigid structure that exhibits little flexibility. C) None of the listed responses is correct. D) Only the proteins in the membrane contribute to its fluidity. E) The fluid characteristic is due to the presence of carbohydrates, and the mosaic characteristic is due to the presence of phospholipids.

A) Proteins in the membrane contribute to the mosaic quality of the membrane while the lateral and rotational movements of phospholipids contribute to its fluidity.

In facilitated diffusion, __________ proteins provide openings in the plasma membrane for substances to flow through without changing structure, and __________ proteins allow passage of substances through the plasma membrane after undergoing a subtle change in shape. A) channel; carrier B) carrier; channel C) peripheral; enzymatic D) receptor; channel E) active transport; signal transduction

A) channel; carrier

All cells have voltages across their membranes. This voltage is called a(n) __________ and is often maintained by __________. A) membrane potential; electrogenic pumps B) iotonic solution; diffusion C) concentration gradient; osmosis D) electrochemical gradient; diffusion E) None of the listed responses is correct.

A) membrane potential; electrogenic pumps

The sodium-potassium pump __________. A) transports sodium ions out of the cell and transports potassium ions into the cell B) transports sodium ions out of the cell C) transports glucose into the cell D) transports potassium ions into the cell E) does not require energy to function

A) transports sodium ions out of the cell and transports potassium ions into the cell

Which of the following substances would be most likely to pass through the plasma membrane without the help of a transport protein? A) Glucose B) A nonpolar molecule, such as a hydrocarbon C) Water D) A large polar molecule E) A negatively charged ion

B) A nonpolar molecule, such as a hydrocarbon

Cells A and B are the same size, shape, and temperature, but cell A is metabolically less active than cell B; cell B is actively converting oxygen to water in cellular respiration. Oxygen will diffuse more rapidly into cell __________ because __________. A) A; the diffusion gradient there is shallower B) B; the diffusion gradient in cell B is steeper C) B; the gradient of oxygen is oriented in the opposite direction compared to cell A D) A; its membrane transport proteins will not be saturated E) B; the oxygen molecules inside cell B have a higher kinetic energy

B) B; the diffusion gradient in cell B is steeper

A nursing infant is able to obtain disease-fighting antibodies, which are large protein molecules, from its mother's milk. These molecules probably enter the cells lining the baby's digestive tract via which process? A) Active transport B) Endocytosis C) Exocytosis D) Passive transport E) Osmosis

B) Endocytosis

Red blood cells contain approximately a 2% concentration of solutes. A red blood cell is placed into a solution that contains a 4% concentration of solutes to which the cell is not permeable. What will happen to the red blood cell? A) Nothing will happen because the solution and the cell are isotonic to each other. B) The cell will decrease in size as water flows out of it. C) The solutes will diffuse into the cell. D) The cell will increase in size as water flows into it. E) The solutes will diffuse out of the cell.

B) The cell will decrease in size as water flows out of it.

Which of the following plant cells would exhibit the most turgor pressure? A) A cell placed in an isotonic solution B) None of the listed responses is correct. C) A cell placed in a hypotonic solution D) A cell placed in a hypertonic solution E) All of the listed responses are correct.

C) A cell placed in a hypotonic solution

How does cholesterol affect membrane fluidity? A) At lower temperatures, it makes the membrane more fluid. B) It allows phospholipids to pack tightly together. C) At body temperature, it makes the membrane less fluid. D) It has no effect on membrane fluidity. E) At body temperature, it makes the membrane more fluid.

C) At body temperature, it makes the membrane less fluid.

Which of these statements describes some aspect of facilitated diffusion? A) Facilitated diffusion of solutes occurs through phospholipid pores in the membrane. B) There is only one kind of protein pore for facilitated diffusion. C) Facilitated diffusion of solutes may occur through channel or transport proteins in the membrane. D) Facilitated diffusion requires energy to drive a concentration gradient. E) Facilitated diffusion is another name for osmosis.

C) Facilitated diffusion of solutes may occur through channel or transport proteins in the membrane.

A cell is placed into a solution and the cell shrinks. Which of the following is true regarding the solution? A) The cell is hypertonic. B) The solution is hypotonic. C) The solution is hypertonic. D) The solution has the same solute concentration as the cell. E) None of the listed responses is correct.

C) The solution is hypertonic.

The internal solute concentration of a plant cell is about 0.8M. To demonstrate plasmolysis, it would be necessary to suspend the cell in what solution? A) 0.8M B) distilled water C) 150m D) 1.0M E) 0.4M

D) 1.0M

Which of the following is a correct difference between active transport and facilitated diffusion? A) Active transport involves transport proteins, and facilitated diffusion does not. B) Facilitated diffusion can move solutes against a concentration gradient, and active transport cannot. C) Facilitated diffusion involves transport proteins, and active transport does not. D) Active transport requires energy from ATP, and facilitated diffusion does not. E) Active transport can move solutes in either direction across a membrane, but facilitated diffusion can only move in one direction.

D) Active transport requires energy from ATP, and facilitated diffusion does not.

Which of the following processes and organelle(s) accounts for the replacement of lipids and proteins lost from the plasma membrane? A) Active transport and the rough endoplasmic reticulum B) Flip-flop of phospholipids from one side of the plasma membrane to the other and the Golgi C) Endocytosis and Golgi D) Exocytosis and smooth and rough ER E) Receptor-mediated endocytosis and smooth ER and Golgi

D) Exocytosis and smooth and rough ER

Which of the following is correct regarding peripheral proteins? A) They exhibit only hydrophobic properties. B) These proteins exhibit both hydrophilic and hydrophobic properties. C) They span the entire phospholipid bilayer. D) These proteins are found only on the surface of the plasma membrane. E) They have no specific function in the plasma membrane.

D) These proteins are found only on the surface of the plasma membrane.

Which of the following molecules is most likely to passively diffuse across the plasma membrane? A) DNA B) Sodium ion C) Hemoglobin D) Glucose E) Carbon dioxide

E) Carbon dioxide

Which of the following structural arrangements of the components in biological membranes facilitates the cell membrane's property of selective permeability? A) A phospholipid bilayer with proteins scattered on the surfaces of the membranes B) Phospholipids sandwiched between two layers of protein C) A layer of protein coating a layer of phospholipid D) Proteins sandwiched between two layers of phospholipids E) Proteins embedded in two layers of phospholipids

E) Proteins embedded in two layers of phospholipids

Which of the following is correct regarding integral proteins? A) They exhibit only hydrophobic properties. B) They have no specific function in the plasma membrane. C) These proteins are found only on the surface of the plasma membrane. D) They exhibit only hydrophilic properties. E) These proteins exhibit both hydrophilic and hydrophobic properties.

E) These proteins exhibit both hydrophilic and hydrophobic properties.