chapter 5 questions

Why does active transport require ATP? A) An input of energy is needed to allow the movement of molecules from an area of low concentration to one of higher concentration. B) An input of energy is needed to both speed up the rate of facilitated diffusion and maintain the conformation of transport proteins. C) An input of energy is needed to maintain the conformation of transport proteins. D) An input of energy is needed to speed up the rate of facilitated diffusion.

A) An input of energy is needed to allow the movement of molecules from an area of low concentration to one of higher concentration

Which one of the following molecules would MOST likely require a transport protein to cross the plasma membrane of a red blood cell? A) C6H12O6 B) H2O C) CO2 D) O2

A) C6H12O6

The plasma membranes of some plant cells use transport proteins to move protons out of the cell against their concentration gradient (from areas of low proton concentration to areas of high proton concentration). This is an example of: A) active transport. B) simple diffusion C) passive transport. D) endocytosis. E) Facilitated diffusion.

A) active transport.

The random movement of molecules from areas of high concentration to low concentration is referred to as: A) diffusion. B) osmosis. C) All of these choices are correct. D) transport.

A) diffusion.

Why does a phospholipid on the cytoplasmic side of the cell membrane rarely flip to the extracellular side if both environments are polar? A) The cholesterol does not allow lipids to move. B) The polar head group cannot pass through the nonpolar interior. C) The two sides have different functions and thus the phospholipid would not function properly. D) The cytoplasmic phospholipid is too big to pass through the membrane.

B) The polar head group cannot pass through the nonpolar interior.

Which of the following molecules does NOT easily diffuse across a plasma membrane? A) small polar molecules B) large polar molecules C) gases D) both small and large polar molecules

B) large polar molecules

Phospholipase is an enzyme that cleaves the phosphate head group off a phospholipid molecule. The plasma membrane is not, however, permeable to the enzyme. Imagine a cell where phospholipid A is present in the layer of phospholipids facing the exterior of the cell, and phospholipid B is present in the layer of phospholipids facing the interior of the cell. After adding phospholipase to the medium in which the cell is growing, what would you expect to find in the fluid surrounding the cell? A) phosphate head groups from both phospholipids A and B B) the phosphate head group from phospholipid A only C) the phosphate head group from phospholipid B only D) phosphate head groups from neither phospholipids A nor B

B) the phosphate head group from phospholipid A only

During osmosis, water moves from a region of _____ to a region of _____. A) low solute concentration; high solute concentration B) high solvent concentration; low solvent concentration C) Both "high solvent concentration; low solvent concentration" AND "low solute concentration; high solute concentration" are correct answers. D) high solute concentration; low solute concentration

C) Both "high solvent concentration; low solvent concentration" AND "low solute concentration; high solute concentration" are correct answers.

Some plant cells take advantage of the high concentration of protons outside the cell to move solutes, such as sucrose, across the plasma membrane into the cell where the sucrose concentration is already relatively high. This type of transport is an example of: A) passive transport. B) osmosis. C) secondary active transport. D) facilitated diffusion.

C) secondary active transport.

As molecules move down their concentration gradient, from a more ordered state to a less ordered state, entropy: Choice A., is increasing. Choice B., is decreasing. Choice C., remains the same.

Choice A., is increasing.

At equilibrium, there will be no net movement of molecules across the cell membrane. Choice A., true Choice B., false

Choice A., true

Simple diffusion of a molecule down its concentration gradient requires an input of energy to the system. Choice A., true Choice B., false

Choice B., false

Molecules that are _____________BLANK and _____________BLANK are able to move across the cell membrane via simple diffusion. Choice A., hydrophobic; large Choice B., hydrophobic; small Choice C., hydrophilic; large Choice D., hydrophilic; small

Choice B., hydrophobic; small

Which of the following correctly describes the movement of water across a selectively permeable membrane during osmosis? Choice A., The water will move from high water concentration to low water concentration. Choice B., The water will move from low solute concentration to high solute concentration. Choice C., Either of these descriptions is correct and equivalent.

Choice C., Either of these descriptions is correct and equivalent.

A container is divided into two compartments by a membrane that is fully permeable to water and small ions. Water is added to one side of the membrane (side A), and a 5% solution of sodium chloride (NaCl) is added to the other (side B). If allowed to reach equilibrium, which of the following would you predict? Choice A., The level of solution on side A will be higher than side B. Choice B., The level of solution on side B will be higher than side A. Choice C., The NaCl concentration on side A and side B will each be 2.5%. Choice D., The NaCl concentration on side A and side B will each be 5%.

Choice C., The NaCl concentration on side A and side B will each be 2.5%.

Which of the following would be the best analogy for an electrochemical gradient across a cellular membrane? Choice A., an electric generator Choice B., a light bulb Choice C., a battery , Choice D., a waterfall Choice E., a water pump

Choice C., a battery ,

A container is divided into two compartments by a membrane that is fully permeable to water but not to larger molecules. Water is added to one side of the membrane (side A), and an equal volume of a 5% solution of glucose is added to the other (side B). What would you predict will happen? Choice A., Glucose will diffuse from side A to side B. Choice B., Glucose will diffuse from side B to side A. Choice C., The water level on side A will increase and on side B will decrease. Choice D., The water level on side B will increase and on side A will decrease.

Choice D., The water level on side B will increase and on side A will decrease.

The defining characteristics of active transport are that this category of transport moves substances _________BLANK their concentration gradient and requires ___________BLANK. Choice A., down; energy Choice B., down; protein transporters Choice C., against; protein transporters Choice D., against; energy Choice E., against; proton pumps

Choice D., against; energy

Diffusion is best described as the random movement of molecules influenced by: Choice A., the thermal energy of the environment. Choice B., energy transferred from molecular collisions in the cell. Choice C., the width of the plasma membrane of the cell. Choice D., the thermal energy of the environment and energy transferred from molecular collisions in the cell. , Choice E., the thermal energy of the environment and the width of the plasma membrane

Choice D., the thermal energy of the environment and energy transferred from molecular collisions in the cell. ,