LS 7A - Week 2 Review Questions

C. a cytoplasm

A bacterial cell, a plant cell, and an animal cell have which structure in common? A. a nucleus B. a vacuole C. a cytoplasm D. a cell wall E. a nucleoid

A. There will be a net movement of salt from side B to side A and net movement of water from side A to side B. During diffusion, molecules move down their concentration gradient from regions of high concentration to those of low concentration. When salt is dissolved in water, the water dilutes the salt, but the salt also dilutes the water. The lowest water concentration would be where the salt concentration is highest.

A beaker contains two solutions of salt dissolved in water. The two solutions have different concentrations of salt (measured by molarity, M) and are separated by a membrane that is permeable to both salt and water. The salt and water will move through the membrane by diffusion. Which statement is true about the diffusion of these solutions? A. There will be a net movement of salt from side B to side A and net movement of water from side A to side B. During diffusion, molecules move down their concentration gradient from regions of high concentration to those of low concentration. When salt is dissolved in water, the water dilutes the salt, but the salt also dilutes the water. The lowest water concentration would be where the salt concentration is highest. B. There will be a net movement of salt from side A to side B and no movement of water. C. There will be a net movement of water from side A to side B and no movement of salt. D. There will be a net movement of both salt and water from side B to side A.

B. peripheral membrane protein.

A protein that is temporarily associated with a biological membrane is a(n): Consider which type of protein is more likely to be weakly tethered to the membrane: a protein that is deeply embedded or a protein that is not deeply embedded. A. transmembrane protein and an integral membrane protein. B. peripheral membrane protein. C. transmembrane protein. D. integral membrane protein.

A. genetic information.

All cells have: A. genetic information. B. internal compartments. C. a cell wall. D. a nucleus.

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

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

C. Animal cells do not have chloroplasts and cell walls, and plant cells do. Because both plants and animals must perform cellular respiration, they both require mitochondria.

How do eukaryotic plant and animal cells differ from one another? A. Animal cells have mitochondria but not chloroplasts, and plant cells have chloroplasts but not mitochondria. B. Animal cells have a plasma membrane, and plant cells have a cell wall. C. Animal cells do not have chloroplasts and cell walls, and plant cells do. Because both plants and animals must perform cellular respiration, they both require mitochondria. D. Animal cells have endoplasmic reticulum, and plant cells don't.

B. Transmembrane proteins would possess a hydrophobic region in the cell interior and a hydrophilic region in the extracellular space.

If cells had single-layer membranes like micelles, how would the structures of transmembrane proteins be affected? A. Transmembrane proteins would only possess hydrophilic regions. B. Transmembrane proteins would possess a hydrophobic region in the cell interior and a hydrophilic region in the extracellular space. C. The structures of transmembrane proteins would remain the same as if cells had lipid bilayers. D. Transmembrane proteins would only possess hydrophobic regions. E. Transmembrane proteins would possess a hydrophilic region in the cell interior and a hydrophobic region in the extracellular space.

D. against; an electrochemical gradient

Refer to Animation: Active Transport. In the example illustrated here, a substance is moved _______ its concentration gradient using the energy of ______________. A. down; ATP B. down; an electrochemical gradient C. against; ATP D. against; an electrochemical gradient

B. a decrease in pH and an increase in ATP

Refer to Animation: Active Transport. In the image, an active transport proton pump drives protons out of the cell using energy from ATP. Under some circumstances pumps like this can be run in reverse. If this pump could be reversed, what would be the result in the cytoplasm? A. an increase in H+ concentration and an increase in ADP B. a decrease in pH and an increase in ATP C. a decrease in H+ concentration and a decrease in ATP D. an increase in the electrochemical gradient E. an increase in pH and an increase in ATP

E. against; energy

Refer to Animation: Active Transport. The defining characteristics of active transport are that this category of transport moves substances _________ their concentration gradient and requires ___________. A. against; protein transporters B. down; protein transporters C. down; energy D. against; proton pumps E. against; energy

A. a battery

Refer to Animation: Active Transport. Which of the answer choices would be the best analogy for an electrochemical gradient across a cellular membrane? A. a battery B. a light bulb C. a waterfall D. an electric generator E. a water pump

D. It is driven by the proton gradient that was created by energy from ATP.

Refer to Animation: Active Transport. Why is the transporter in the figure considered to be an example of "secondary transport"? A. The two transported substances are moving in opposite directions. B. It is driven by ATP which was created by energy from a proton gradient. C. It is moving two substances. D. It is driven by the proton gradient that was created by energy from ATP.

B. is increasing.

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

A. true

Refer to Animation: Diffusion. At equilibrium, there will be no net movement of molecules across the cell membrane. A. true B. false

B. the thermal energy of the environment and energy transferred from molecular collisions in the cell. energy transferred from molecular collisions in the cell.

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

B. hydrophobic; small

Refer to Animation: Diffusion. Molecules that are _____________ and _____________ are able to move across the cell membrane via simple diffusion. A. hydrophobic; large B. hydrophobic; small C. hydrophilic; small D. hydrophilic; large

A. false

Refer to Animation: Diffusion. Simple diffusion of a molecule down its concentration gradient requires an input of energy to the system. A. false B. true

B. The head groups are repelled by the hydrophobic membrane interior.

Refer to Animation: Fluid Mosaic Model. Although the phospholipid molecules can be in constant lateral movement, they very rarely flip from one side of the bilayer to the other. Which of the answer choices could explain this? A. The cholesterol keeps the phospholipids on the correct side. B. The head groups are repelled by the hydrophobic membrane interior. C. The molecular attraction between the fatty acid tails is too strong. D. The head groups are too large to fit between the interior fatty acid tails.

C. The laser light destroys the dye fluorescence.

Refer to Animation: Fluid Mosaic Model. In the experiment that showed membrane fluidity, what was the purpose of shining a laser on the membrane? A. The laser light allows the dye to be seen with the microscope. B. The laser light makes the proteins fluorescent. C. The laser light destroys the dye fluorescence.

A. line D

Refer to Animation: Fluid Mosaic Model. The image illustrates our understanding of how typical cell membranes are structured. Which arrow is pointing at a cholesterol? A. line D B. line B C. line C D. line A

D. Line B

Refer to Animation: Fluid Mosaic Model. The image illustrates our understanding of how typical cell membranes are structured. Which arrow is pointing at the hydrophilic head group of a phospholipid? A. line C B. line D C. line A D. line B

C. Line A

Refer to Animation: Fluid Mosaic Model. The image illustrates our understanding of how typical cell membranes are structured. Which line is pointing at a protein? A. line C B. line D C. line A D. line B

A. integral membrane proteins, cholesterol, and phospholipids

Refer to Animation: Fluid Mosaic Model. Which of the types of molecules depicted in the figure is amphipathic? A. integral membrane proteins, cholesterol, and phospholipids B. phospholipids C. cholesterol D. integral membrane proteins

A. The water will be higher on side A than on side B.

Refer to Animation: Osmosis. A beaker is divided by a membrane that is permeable to water and glucose, but not to sucrose. Equal volumes of solutions are added to side A and B with the initial concentrations as shown below. Initially, the liquid levels on both sides are the same. After the system described above reaches equilibrium, what can you predict about the water levels? A. The water will be higher on side A than on side B. B. The water level will be the same on both sides. C. The water will be higher on side B than on side A.

C. 0.75 M

Refer to Animation: Osmosis. A beaker is divided by a membrane that is permeable to water and glucose, but not to sucrose. Equal volumes of solutions are added to side A and B with the initial concentrations as shown below. Initially, the liquid levels on both sides are the same. After the system described above reaches equilibrium, what will be the concentration of glucose on side B? A. 1.0 M B. The answer cannot be determined from the information provided. C. 0.75 M D. 0.5 M

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

Refer to Animation: Osmosis. 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 answer choices would you predict? A. The NaCl concentration on side A and side B will each be 2.5%. B. The level of solution on side A will be higher than side B. C. The NaCl concentration on side A and side B will each be 5%. D. The level of solution on side B will be higher than side A.

C. The water level on side B will increase and on side A will decrease.

Refer to Animation: Osmosis. 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? A. Glucose will diffuse from side A to side B. B. Glucose will diffuse from side B to side A. C. The water level on side B will increase and on side A will decrease. D. The water level on side A will increase and on side B will decrease.

A. Either of these descriptions is correct and equivalent.

Refer to Animation: Osmosis. Which of the answer choices correctly describes the movement of water across a selectively permeable membrane during osmosis? A. Either of these descriptions is correct and equivalent. B. The water will move from low solute concentration to high solute concentration. C. The water will move from high water concentration to low water concentration.

C. secondary active transport.

Some plant cells create a 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. facilitated diffusion. C. secondary active transport. D. osmosis.

C. hydrophobic.

The interior region of a phospholipid bilayer is characterized as: A. hydrophilic. B. polar. C. hydrophobic. D. hydrophilic and polar.

A. phospholipids and cholesterol.

The lipid components of cellular membranes often include: A. phospholipids and cholesterol. B. fatty acids and cholesterol. C. phospholipids and fatty acids. D. phospholipids.

D. cholesterol

The plasma membrane is composed of a phospholipid bilayer and associated proteins. What else is commonly found in the plasma membranes of animal cells? A. nucleic acids B. amino acids C. ethanol D. cholesterol

C. active transport.

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

B. diffusion.

The random movement of molecules within a solution is referred to as: A. transport. B. diffusion. C. translation. D. osmosis

E. the Golgi apparatus

Which eukaryotic cell structure plays a role in protein trafficking and sorting? A. lysosomes B. vacuoles C. peroxisomes D. mitochondria E. the Golgi apparatus

B. lysosome

Which eukaryotic organelle is associated with the breakdown of macromolecules? A. the Golgi apparatus B. lysosome C. endoplasmic reticulum D. mitochondria

B. gases like O2 and CO2 Gases are uncharged, small molecules that can pass easily through the membrane.

Which molecules can easily diffuse across a plasma membrane? A. large polar molecules B. gases like O2 and CO2 Gases are uncharged, small molecules that can pass easily through the membrane. C. small charged molecules, such as ions D. proteins

B. An input of energy is needed to allow the movement of molecules from an area of low concentration to one of higher concentration. Diffusion leads to equalization of the concentration of molecules in different regions. Active transport results in unequal concentrations of molecules in different regions, which requires movement of molecules against the concentration gradient.

Why does active transport of molecules across a membrane require ATP? A. An input of energy is needed to speed up the rate of facilitated diffusion. B. An input of energy is needed to allow the movement of molecules from an area of low concentration to one of higher concentration. Diffusion leads to equalization of the concentration of molecules in different regions. Active transport results in unequal concentrations of molecules in different regions, which requires movement of molecules against the concentration gradient. C. An input of energy is needed because the movement of molecules requires the synthesis of additional membrane. D. An input of energy is needed to move all molecules across a membrane.