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chapter 7 bio mastering

Terms in this set (55)

What is the function of Structure E?

a) transport across the plasma membrane
b) structural support of the cell
c) cell-cell communication
d) stabilization of the phospholipids
e) detection of environmental change
d
Identify Structure D.
a) cholesterol
b) extracellular matrix
c) glycoprotein
d) phospholipid bilayer of membrane
e) protein
d
Identify Structure A.
a) protein
b) phospholipid
c) cholesterol
d) extracellular matrix
e) glycoprotein
e
Which of the following statements about a typical plasma membrane is correct?
a) The hydrophilic interior of the membrane is composed primarily of the fatty acid tails of the phospholipids.
b) Carbohydrates on the membrane surface are important in determining the overall bilayer structure.
c) The two sides of the plasma membrane have different lipid and protein composition.
d) The plasma membrane is a covalently linked network of phospholipids and proteins that controls the movement of solutes into and out of a cell.
e) Phospholipids are the primary component that determines which solutes can cross the plasma membrane.
c
Which of the following best describes the structure of a biological membrane?

a) a mixture of covalently linked phospholipids and proteins that determines which solutes can cross the membrane and which cannot
b) two layers of phospholipids (with opposite orientations of the phospholipids in each layer) with each layer covered on the outside with proteins
c) two layers of phospholipids with proteins either crossing the layers or on the surface of the layers
d) a fluid structure in which phospholipids and proteins move freely between sides of the membrane
e) two layers of phospholipids with proteins embedded between the two layers
c
The permeability of a biological membrane to a specific polar solute depends primarily on which of the following?

a) the amount of cholesterol in the membrane
b) the types of transport proteins in the membrane
c) the phospholipid composition of the membrane
d) the presence of unsaturated fatty acids in the membrane
e) the types of polysaccharides present in the membrane
b
Which of the following is least likely to be important in holding the components of a biological membrane together?
a) covalent interactions between the phospholipid and protein components of the membrane
b) hydrophobic interactions among the fatty acid tails of phospholipids on opposite sides of the membrane
c) polar interactions among the phospholipid head groups on the same surface of the membrane
d) hydrophobic interactions between the phospholipid tails and the surface of integral membrane proteins buried in the membrane
e) hydrophobic interactions among the fatty acid tails of phospholipids on the same side of the membrane
a
For a protein to be an integral membrane protein, it would have to be _____.
a) exposed on only one surface of the membrane
b) hydrophilic
c) amphipathic, with at least one hydrophobic region
d) hydrophobic
c
According to the fluid mosaic model of cell membranes, phospholipids _____.
a) can move laterally along the plane of the membrane
b) frequently flip-flop from one side of the membrane to the other
c) have hydrophilic tails in the interior of the membrane
d) occur in an uninterrupted bilayer, with membrane proteins restricted to the surface of the membrane
a
Why are lipids and proteins free to move laterally in membranes?
a. There are only weak hydrophobic interactions in the interior of the membrane.
b. Hydrophilic portions of the lipids are in the interior of the membrane.
c. Lipids and proteins repulse each other in the membrane.
d. The interior of the membrane is filled with liquid water.
a
In what way do the membranes of a eukaryotic cell vary?
a. Certain proteins are unique to each membrane.
b. Only certain membranes of the cell are selectively permeable.
c. Phospholipids are found only in certain membranes.
d. Some membranes have hydrophobic surfaces exposed to the cytoplasm, while others have hydrophilic surfaces facing the cytoplasm.
a
Which of the following statements is a reasonable explanation for why unsaturated fatty acids help keep a membrane more fluid at lower temperatures?
a. The double bonds form kinks in the fatty acid tails, preventing adjacent lipids from packing tightly.
b. The double bonds block interaction among the hydrophilic head groups of the lipids.
c. Unsaturated fatty acids are more nonpolar than saturated fatty acids.
d. Unsaturated fatty acids have a higher cholesterol content, which prevents adjacent lipids from packing tightly.
a
Structure A in the figure is a(n) _____.
a. transport protein
b. antibody
c. enzyme
d. receptor molecule
e. structural protein
a
Which of these can RAPIDLY pass directly through the phospholipids of the plasma membrane, without the help of a transport protein?
a. A only
b. B only
c. C only
d. D only
e. B, C, and D
a
What kinds of molecules pass through a cell membrane most easily?
a. large and hydrophobic
b. small and ionic
c. small and hydrophobic
d. large polar
c
Which of the following statements describes a characteristic feature of a carrier protein in a plasma membrane?
a. It requires the expenditure of cellular energy to function.
b. It exhibits specificity for a particular type of molecule.
c. It works against diffusion.
d. It has no hydrophobic regions.
b
Which of the following molecules dramatically increases the rate of diffusion of water across cell membranes?
a. aquaporins
b. gated ion channels
c. the sodium-potassium pump
d. ATP
a
A research team is working on the design of a new drug for the treatment of lung cancer. To be most effective, this drug must specifically enter the cytoplasm of lung cells while not entering the cells of other tissues. Which of the following characteristics would likely enhance the specificity of this drug?
a. similarity of the drug molecule to other molecules normally transported lung cells
b. specificity of the drug molecule for binding to the extracellular matrix of lung cells
c. the relative hydrophobicity of the drug molecule
d. phospholipid composition of lung cell plasma membranes
a
A semipermeable membrane is placed between the following solutions.
Which solution will decrease in volume?

a. Solution A: 1.4% (m/v) starch
b. Solution B: 7.62% (m/v) starch
a
Which solution will increase in volume?
a. Solution C: 9% (m/v) NaCl
b. Solution D: 12.4% (m/v) NaCl
b
Crenation
This happens when a cell shrinks and shrivels; can result in cell death if severe.
hemolysis
destruction of red blood cells
Which of the following factors does not affect membrane permeability?
a. The amount of cholesterol in the membrane
b. The polarity of membrane phospholipids
c. Temperature
d. The saturation of hydrocarbon tails in membrane phospholipids
b
How can a lipid be distinguished from a sugar?
a. Lipids are mostly nonpolar.
b. A lipid dissolves in water.
c. Lipids are mostly saturated.
d. A lipid is made up of only hydrocarbons.
a
True or false? Osmosis is a type of diffusion.
a. True
b. False
a
What property of dishwashing liquid (detergent) makes it useful to wash grease from pans?
a. Hydrophobic nature
b. Permeability
c. Amphipathic nature
d. Solubility in water
c
Which of the following particles could diffuse easily through a cell membrane?
a. Glucose
b. Sodium ion (Na+)
c. Oxygen (O2)
d. Hydrogen ion (H+)
c
True or false? The water-soluble portion of a phospholipid is the polar head, which generally consists of a glycerol molecule linked to a phosphate group.
a. True
b. False
a
If a red blood cell is placed in a salt solution and bursts, what is the tonicity of the solution relative to the interior of the cell?
a. Hypertonic
b. Hypotonic
c. Osmotic
d. Isotonic
b
Facilitated diffusion is a type of _______.
a. phagocytosis
b. active transport
c. pinocytosis
d. passive transport
d
Structure A is a _____. (triangle)

a. transport protein
b. solvent
c. solute
d. phospholipid
e. water molecule
c
Structure B is a _____. (purple thing)
a. solvent
b. water molecule
c. phospholipid
d. solute
e. transport protein
e
Which of the following statements about diffusion is true?
a. It is an active process in which molecules move from a region of lower concentration to a region of higher concentration.
b. It requires an expenditure of energy by the cell.
c. It is a passive process in which molecules move from a region of higher concentration to a region of lower concentration.
d. It is very rapid over long distances.
c
When a cell is in equilibrium with its environment, which of the following processes occurs for substances that can diffuse through the plasma membrane?
a. There is random movement of substances into and out of the cell.
b. There is no movement of substances into or out of the cell.
c. There is directed movement of substances into and out of the cell.
d. All movement of molecules across the plasma membrane occurs by active transport.
a
The solutions in the two arms of this U-tube are separated by a membrane that is permeable to water and glucose but not to sucrose. Side A is half-filled with a solution of 2 M sucrose and 1 M glucose. Side B is half-filled with 1 M sucrose and 2 M glucose. Initially, the liquid levels on both sides are equal.

In the U-tube illustrated above, ________.
a. side A is hypotonic to side B
b. side A is hypertonic to side B
c. side A is more turgid than side B
d. side A is isotonic to side B
a
The solutions in the two arms of this U-tube are separated by a membrane that is permeable to water and glucose but not to sucrose. Side A is half-filled with a solution of 2 M sucrose and 1 M glucose. Side B is half-filled with 1 M sucrose and 2 M glucose. Initially, the liquid levels on both sides are equal.

Which of the following will be true when the system illustrated above reaches equilibrium?

a. The water levels will be unchanged.
b. The water level will be higher in side A than in side B.
c. The water level will be higher in side B than in side A.
d. The concentration of sucrose on side A will be greater than the concentration of sucrose on side B.
b
A patient was involved in a serious accident and lost a large quantity of blood. In an attempt to replenish body fluids, distilled water equal to the volume of blood lost is added to the blood directly via one of his veins. What will be the most probable result of this transfusion?


a. The patient's red blood cells will shrivel up because the blood has become hypertonic compared to the cells.
b. The patient's red blood cells will swell and possibly burst because the blood has become hypotonic compared to the cells.
c. The patient's red blood cells will burst because the blood has become hypertonic compared to the cells.
d The patient's red blood cells will shrivel up because the blood has become hypotonic compared to the cells.
b
What will happen to a red blood cell (RBC), which has an internal ion content of about 0.9%, if it is placed into a beaker of pure water?

a. The cell would shrink because the water in the beaker is hypotonic relative to the cytoplasm of the RBC.
b. The cell would shrink because the water in the beaker is hypertonic relative to the cytoplasm of the RBC.
c. The cell would swell because the water in the beaker is hypotonic relative to the cytoplasm of the RBC.
d. The cell will remain the same size because the solution outside the cell is isotonic.
c
Celery stalks that are immersed in fresh water for several hours become stiff. Similar stalks left in a 0.15 M salt solution become limp. From this we can deduce that the fresh water_____.

a. is hypotonic and the salt solution is hypertonic to the cells of the celery stalks
b. is hypertonic and the salt solution is hypotonic to the cells of the celery stalks
c. and the salt solution are both hypertonic to the cells of the celery stalks
d. is isotonic and the salt solution is hypertonic to the cells of the celery stalks
a
Which of the following statements is TRUE with regard to this animation?
a. Potassium ions are transported down their concentration gradient.
b. The cell does not expend ATP.
c. Both sodium and potassium ions are transported against their concentration gradients.
d. Sodium ions are transported down their concentration gradient.
e. The cell is not expending energy.
c
The movement of glucose into a cell against a concentration gradient is most likely to be accomplished by which of the following?

a. cotransport of the glucose with a proton or sodium ion that was pumped across the membrane
b. using the energy of ATP hydrolysis receptor-mediated endocytosis
c. passive diffusion of the glucose through the lipid bilayer
d. movement of glucose into the cell through a glucose channel
e. facilitated diffusion of the glucose using a carrier protein
a
Active and passive transport of solutes across a membrane typically differ in which of the following ways?
a. Active transport uses protein carriers, whereas passive transport uses carbohydrate carriers.
b. Active transport is used for ions, passive transport is used for uncharged solutes.
c. Active transport always involves the utilization of cellular energy, whereas passive transport does not require cellular energy.
d. Active transport is usually down the concentration gradient of the solute, whereas passive transport is always against the concentration gradient of the solute.
e. Active transport is always faster than passive transport.
c
Which of the following membrane activities requires energy from ATP hydrolysis?

a. movement of glucose molecules into a bacterial cell from a medium containing a higher concentration of glucose than inside the cell
b. movement of Na+ ions from a lower concentration in a mammalian cell to a higher concentration in the extracellular fluid
c. facilitated diffusion of chloride ions across the membrane through a chloride channel
d. movement of carbon dioxide out of a paramecium
b
Several epidemic microbial diseases of earlier centuries incurred high death rates because they resulted in severe dehydration due to vomiting and diarrhea. Today they are usually not fatal because we have developed which of the following types of treatments?
a. medications to slow blood loss
b. antiviral medications that are efficient and work well with most viruses
c. intravenous feeding techniques
d. hydrating drinks with high concentrations of salt and glucose
d
The force driving simple diffusion is ________, while the energy source for active transport is ________.
a. transmembrane pumps; an electrochemical gradient
b. a concentration gradient; ATP hydrolysis
c. a concentration gradient; ADP
d. phosphorylated carrier proteins; ATP
b
Endocytosis moves materials _____ a cell via _____.
a. into ... a transport protein
b. into ... facilitated diffusion
c. out of ... membranous vesicles
d. out of ... diffusion
e. into ... membranous vesicles
e
You can recognize the process of pinocytosis when _____.

a. the cell is engulfing extracellular fluid
b. a receptor protein is involved
c. the cell is engulfing a large particle
a
A white blood cell engulfing a bacterium is an example of _____.
a. facilitated diffusion
b. exocytosis
c. pinocytosis
d. phagocytosis
e. receptor-mediated endocytosis
d
An organism with a cell wall would most likely be unable to take in materials through _____.
a. facilitated diffusion
b. osmosis
c. phagocytosis
d. active transport
c
White blood cells engulf bacteria using _____.
a. receptor-mediated exocytosis
b. phagocytosis
c. pinocytosis
d. osmosis
b
Familial hypercholesterolemia is characterized by _____.
a. a poorly formed lipid bilayer that cannot incorporate cholesterol into cell membranes
b. defective LDL receptors on the cell membranes
c. poor attachment of the cholesterol to the extracellular matrix of cells
d. inhibition of the cholesterol active transport system in red blood cells
b
A bacterium engulfed by a white blood cell through phagocytosis will be digested by enzymes contained in _____.

a. Golgi vesicles
b. lysosomes
c. vacuoles
d. secretory vesicles
b
In what way do membranes vary among eukaryotic cells?
a. Phospholipids are found only in certain membranes.
b. Some membranes have hydrophobic surfaces exposed to the cytoplasm, while others have hydrophilic surfaces facing the cytoplasm.
c. Only certain membranes are constructed from amphipathic molecules.
d. Only certain membranes of the cell are selectively permeable.
e. Certain proteins are unique to each membrane.
e
Which factors affect the rate of osmotic movement of water

a. Hydrostatic pressure applied to a hypertonic solution separated from a hypotonic solution by a selectively permeable membrane increases osmotic movement across the membrane.
b. No factors have an effect; the rate of osmosis is constant.
c. The rate of osmosis increases with increasing differences in solute concentrations between two solutions separated by a selectively permeable membrane.
c
What happens when two solutions separated by a selectively permeable membrane reach osmotic equilibrium?
a. Water molecules continue to move from the hypotonic solution to the hypertonic solution.
b. Water molecules move between the two solutions, but there is no net movement of water across the membrane.
c. Water molecules no longer move between the solutions.
b
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