Chapter 7 Module

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) 1.0M B) 0.8M C) 0.4M D) distilled water E) 150m

A) 1.0M

Why is energy required for active transport? A) Because it moves solutes against their concentration gradient B) Because it helps maintain water balance in cells without walls C) To allow the movement of water from a hypotonic solution to a hypertonic solution D) To allow the movement of water from a hypotonic solution to a hypertonic solution E) To allow the movement of solutes down their concentration gradient

A) Because it moves solutes against their concentration gradient

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

A) Carbon dioxide

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) Endocytosis B) Passive transport C) Osmosis D) Exocytosis E) Active transport

A) Endocytosis

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) They are triacylglycerols, which are commonly available in foods. C) Phospholipids form a single sheet in water. D) Phospholipids are completely insoluble in water. E) Phospholipids form a structure in which the hydrophobic portion faces outward.

A) Phospholipids form a selectively permeable structure.

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

B) Cell-to-cell recognition

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

B) Plasma membrane

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

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

Which of the following statements concerning carbohydrates associated with the plasma membrane is correct? A) Carbohydrates associated with the plasma membrane are located on both surfaces of the membrane. B) The carbohydrate composition of most eukaryotic plasma membranes is quite similar. C) Membrane carbohydrates function primarily in cell-cell recognition. D) Carbohydrates are only found associated with the membranes of prokaryotic cells. E) Carbohydrates on the plasma membrane are typically short chains of between two and five monosaccharides.

C) Membrane carbohydrates function primarily in cell-cell recognition.

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

C) Proteins embedded in two layers of phospholipids

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) peripheral; enzymatic B) active transport; signal transduction C) channel; carrier D) carrier; channel E) receptor; channel

C) channel; carrier

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

D) A large polar molecule

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) Water C) A large polar molecule D) A nonpolar molecule, such as a hydrocarbon E) A negatively charged ion

D) A nonpolar molecule, such as a hydrocarbon

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

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

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) B; the gradient of oxygen is oriented in the opposite direction compared to cell A B) B; the oxygen molecules inside cell B have a higher kinetic energy C) A; the diffusion gradient there is shallower D) B; the diffusion gradient in cell B is steeper E) A; its membrane transport proteins will not be saturated

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

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 gain water by osmosis; the red blood cell would burst, and the plant cell would increase in turgor pressure. B) The red blood cell would burst, and the plant cell would shrink. C) 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. D) Both cells would lose water; the red blood cell would shrivel, and the plant plasma membrane would pull away from the cell wall. E) The red blood cell would shrink, and the plant cell would gain water.

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

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

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

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

D) It is a passive process.

Which of the following molecules are most abundant in the plasma membrane? A) Water B) Carbohydrates C) Proteins D) Phospholipids E) Cholesterol

D) Phospholipids

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

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

The plasma membrane exhibits selective permeability. This means that __________. A) proteins in the membrane do not affect its permeability B) the structure of the plasma membrane does not affect its permeability C) the plasma membrane allows any substance to flow through it easily D) the plasma membrane allows some substances to flow through it more easily than others E) the plasma membrane does not allow any substance to flow through it

D) the plasma membrane allows some substances to flow through it more easily than others

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

E) A cell placed in a hypotonic solution

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

E) 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) Flip-flop of phospholipids from one side of the plasma membrane to the other and the Golgi B) Active transport and the rough endoplasmic reticulum C) Receptor-mediated endocytosis and smooth ER and Golgi D) Endocytosis and Golgi E) Exocytosis and smooth and rough ER

E) Exocytosis and smooth and rough ER

Which of the following statements about passive transport is correct? A) Passive transport operates independently of the concentrations of the moving solute. B) In passive transport, solute movement stops when the solute concentration is the same on both sides of the membrane. C) Passive transport operates independently of diffusion. D) Passive transport does not occur in the human body. E) 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.

E) 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.

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) The solutes will diffuse into the cell. B) Nothing will happen because the solution and the cell are isotonic to each other. C) The cell will increase in size as water flows into it. D) The solutes will diffuse out of the cell. E) The cell will decrease in size as water flows out of it.

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

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

E) The solution is hypertonic.

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

E) These proteins exhibit both hydrophilic and hydrophobic properties.

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

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