Question 1

A unicellular organism adapted to living in salt water is placed in a freshwater tank.What is the likely outcome?

Accepted Answer

A)  Water moves into the cell, causing it to burst. 
B)  Water moves out of the cell, causing it to shrivel. 
C)  Water moves into the cell until the organism can adapt. 
D)  Water moves out of the cell until the organism can adapt. 
E)  Water and salt move in opposite directions until the organism can adapt. 
A)  Water moves into the cell, causing it to burst. 
B)  Water moves out of the cell, causing it to shrivel. 
C)  Water moves into the cell until the organism can adapt. 
D)  Water moves out of the cell until the organism can adapt. 
E)  Water and salt move in opposite directions until the organism can adapt.

Question 2

The difference between osmosis and diffusion is that

Accepted Answer

A)  diffusion is passive transport, whereas osmosis is active transport. 
B)  only in diffusion do molecules move from areas of high concentration to areas of low concentration. 
C)  only diffusion refers to the movement of materials across a semipermeable membrane. 
D)  osmosis refers specifically to the movement of water, whereas diffusion is the movement of any molecule. 
E)  the process of osmosis varies according to the kinds of particles present. 
A)  diffusion is passive transport, whereas osmosis is active transport. 
B)  only in diffusion do molecules move from areas of high concentration to areas of low concentration. 
C)  only diffusion refers to the movement of materials across a semipermeable membrane. 
D)  osmosis refers specifically to the movement of water, whereas diffusion is the movement of any molecule. 
E)  the process of osmosis varies according to the kinds of particles present.

Question 3

You are studying the effects of different substances on frog heart muscle cells.You treat the cells with a substance that blocks gap junctions.What do you expect will occur?

Accepted Answer

A)  The cells will not be able to maintain their structure. 
B)  The gap junctions will not be able to provide stability. 
C)  The electric current will not spread evenly to adjacent heart cells. 
D)  Nutrients will not pass between the cells. 
E)  Nerve impulses will not be transmitted to the cells. 
A)  The cells will not be able to maintain their structure. 
B)  The gap junctions will not be able to provide stability. 
C)  The electric current will not spread evenly to adjacent heart cells. 
D)  Nutrients will not pass between the cells. 
E)  Nerve impulses will not be transmitted to the cells.

Question 4

Refer to the graph below showing the relationship between glucose concentration outside a cell and the rate of facilitated diffusion of glucose across a cell membrane via carrier proteins.   Which label on the graph represents saturation of the carrier proteins?

Accepted Answer

The answer of Refer to the graph below showing the...

Question 5

Very high cholesterol levels in those with familial hypercholesterolemia are cause by

Accepted Answer

A)  hyperactive aquaporins. 
B)  the inability to hydrolyze ATP. 
C)  deficient LDL receptor proteins. 
D)  malformed gap junctions. 
E)  defective ion channels. 
A)  hyperactive aquaporins. 
B)  the inability to hydrolyze ATP. 
C)  deficient LDL receptor proteins. 
D)  malformed gap junctions. 
E)  defective ion channels.

Question 6

Refer to the figures below.   Which statement accurately describes the solutions surrounding the three cells shown in the figures, and in which case will there be a net flow of water out of the cell?

Accepted Answer

A)  A = hypotonic, B = isotonic, C = hypertonic, with net water flow outward from cell C 
B)  A = hypertonic, B = hypotonic, C = isotonic, with net water flow outward from cell A 
C)  A = isotonic, B = hypertonic, C = hypotonic, with net water flow outward from cell B 
D)  A = hypertonic, B = isotonic, C = hypotonic, with net water flow outward from cell C 
E)  A = hypotonic, B = hypotonic, C = hypertonic, with net water flow outward from cell A 
A)  A = hypotonic, B = isotonic, C = hypertonic, with net water flow outward from cell C 
B)  A = hypertonic, B = hypotonic, C = isotonic, with net water flow outward from cell A 
C)  A = isotonic, B = hypertonic, C = hypotonic, with net water flow outward from cell B 
D)  A = hypertonic, B = isotonic, C = hypotonic, with net water flow outward from cell C 
E)  A = hypotonic, B = hypotonic, C = hypertonic, with net water flow outward from cell A

Question 7

Refer to the figure and table below.     Vitamin B12 is an essential vitamin that humans must acquire from their diets.Within the small intestine, vitamin B12 is taken up by receptor-mediated endocytosis as shown in the figure.The protein labeled IF binds to vitamin B12 molecules in the intestinal lumen, forming a complex.This complex is recognized by the IF receptor present on intestinal cells and stimulates endocytosis when it binds.Vitamin B12 by itself does not bind to the receptor.Individuals known to carry a mutation in either the IF protein or the IF receptor are represented in the table, along with observations about whether symptoms of vitamin B12 deficiency are present.If a drug molecule could be produced that would bind to vitamin B12 and stimulate uptake by intestinal cells, which individual(s) would be expected to benefit, based on the information given?

Accepted Answer

A)  Individual 1 only 
B)  Individual 2 only 
C)  Individual 3 only 
D)  Individuals 1 and 2 only 
E)  Individuals 2 and 3 only 
A)  Individual 1 only 
B)  Individual 2 only 
C)  Individual 3 only 
D)  Individuals 1 and 2 only 
E)  Individuals 2 and 3 only

Question 8

Water moves across a cell membrane through a channel protein, whereas glucose moves across a cell membrane via a carrier protein.Which statement provides a valid comparison of these two membrane transport systems?

Accepted Answer

A)  Water transport occurs without the cell using energy, whereas glucose transport requires energy input by the cell. 
B)  Glucose moves in a direction from high to low concentration, while water moves in a direction that is not governed by differing solute concentrations. 
C)  A cell can add more sites for water transport to increase water movement across the membrane but cannot achieve the same result for glucose using a similar strategy. 
D)  Genetic mutations can alter glucose transport into a cell but cannot alter water transport. 
E)  Several water molecules move one after the other through the opening provided by a channel protein, while glucose is transported across the membrane via a carrier protein one molecule at a time. 
A)  Water transport occurs without the cell using energy, whereas glucose transport requires energy input by the cell. 
B)  Glucose moves in a direction from high to low concentration, while water moves in a direction that is not governed by differing solute concentrations. 
C)  A cell can add more sites for water transport to increase water movement across the membrane but cannot achieve the same result for glucose using a similar strategy. 
D)  Genetic mutations can alter glucose transport into a cell but cannot alter water transport. 
E)  Several water molecules move one after the other through the opening provided by a channel protein, while glucose is transported across the membrane via a carrier protein one molecule at a time.

Question 9

Refer to the figure below, which is being created to illustrate secondary active transport.   The small red circles represent the molecules being transported, and the H+ symbols represent hydrogen ions.The natural concentration gradient of the red molecules is shown.The hydrogen ion gradient was established by a membrane protein that is not shown.Given this information, which symbol should appear in the oval to indicate the direction of movement of hydrogen ions and red molecules?

Accepted Answer

A)    
B)    
C)    
D)    
E)    
A)    
B)    
C)    
D)    
E)

Question 10

Refer to the table below.   Which statement about biological membranes is supported by these data?

Accepted Answer

A)  All membranes share a similar fluid mosaic structure but are able to perform diverse functions because of differences in their membrane proteins. 
B)  Biological membranes consist of a lipid bilayer with the hydrophobic tails of lipids facing inward and hydrophilic groups facing outward. 
C)  Membranes in cells are dynamic structures in which both lipid and protein components can move laterally throughout the plane of the membrane. 
D)  Proteins are embedded within the lipid bilayer of most biological membranes asymmetrically, with more proteins present in the layer closer to the cytoplasm. 
E)  Carbohydrate groups extend outward from the lipid bilayer of biological membranes, protruding into either the cytoplasm or the external environment. 
A)  All membranes share a similar fluid mosaic structure but are able to perform diverse functions because of differences in their membrane proteins. 
B)  Biological membranes consist of a lipid bilayer with the hydrophobic tails of lipids facing inward and hydrophilic groups facing outward. 
C)  Membranes in cells are dynamic structures in which both lipid and protein components can move laterally throughout the plane of the membrane. 
D)  Proteins are embedded within the lipid bilayer of most biological membranes asymmetrically, with more proteins present in the layer closer to the cytoplasm. 
E)  Carbohydrate groups extend outward from the lipid bilayer of biological membranes, protruding into either the cytoplasm or the external environment.

Question 11

When placed in water, wilted plants regain their leaf turgor because of the

Accepted Answer

A)  active transport of salts from the water into the plant cells. 
B)  active transport of salts from the plant cells into the water. 
C)  osmosis of water into the plant cells. 
D)  osmosis of water out of the plant cells. 
E)  diffusion of water out of the plant cells. 
A)  active transport of salts from the water into the plant cells. 
B)  active transport of salts from the plant cells into the water. 
C)  osmosis of water into the plant cells. 
D)  osmosis of water out of the plant cells. 
E)  diffusion of water out of the plant cells.

Question 12

Solution X is hypotonic relative to solution Y if X has a solute concentration that is _______ the solute concentration of Y.

Accepted Answer

The answer of Solution X is hypotonic relative to solution...

Question 13

Primary active transport requires energy released from the hydrolysis of _______.

Accepted Answer

The answer of Primary active transport requires energy released from...

Question 14

Refer to the figure below.   Which statement regarding channel proteins shown in the figure is false?

Accepted Answer

A)  Channel proteins can assist polar molecules to cross the plasma membrane by facilitated diffusion. 
B)  The gated ion channel can allow ions to pass when stimulated to open. 
C)  The surface of a channel protein in contact with the bilayer would likely have hydrophilic amino acids. 
D)  Water plays a role in determining which ions are allowed to pass through an ion channel. 
E)  Aquaporins are channel proteins that facilitate the diffusion of water across membranes. 
A)  Channel proteins can assist polar molecules to cross the plasma membrane by facilitated diffusion. 
B)  The gated ion channel can allow ions to pass when stimulated to open. 
C)  The surface of a channel protein in contact with the bilayer would likely have hydrophilic amino acids. 
D)  Water plays a role in determining which ions are allowed to pass through an ion channel. 
E)  Aquaporins are channel proteins that facilitate the diffusion of water across membranes.

Question 15

A biologist wants to compare the integral membrane protein content of cells from mouse liver, pancreas, and intestine.Which experimental procedure should she choose?

Accepted Answer

A)  Compare the patterns of bumps observed when cells of each type are subjected to freeze-fracture electron microscopy. 
B)  Perform three cell fusion experiments in which each cell type is labeled, fused with another labeled cell, and observed to see how rapidly the labels mix together. 
C)  Hold mice in environments of varying temperatures, then analyze and compare the fluidities of membranes isolated from each cell type. 
D)  Treat intact cells with enzymes that hydrolyze peptide bonds, then test whether the cells have lost their ability to bind to various small molecules, such as glucose. 
E)  Carry out chemical analyses of the phospholipid composition of membranes isolated from each cell type, then compare the results. 
A)  Compare the patterns of bumps observed when cells of each type are subjected to freeze-fracture electron microscopy. 
B)  Perform three cell fusion experiments in which each cell type is labeled, fused with another labeled cell, and observed to see how rapidly the labels mix together. 
C)  Hold mice in environments of varying temperatures, then analyze and compare the fluidities of membranes isolated from each cell type. 
D)  Treat intact cells with enzymes that hydrolyze peptide bonds, then test whether the cells have lost their ability to bind to various small molecules, such as glucose. 
E)  Carry out chemical analyses of the phospholipid composition of membranes isolated from each cell type, then compare the results.

Question 16

Refer to the figure below.   The type of cell junction shown is most efficient in

Accepted Answer

A)  animal cells that require a tight structure. 
B)  animal cells that conduct electrical activity, as in the heart. 
C)  muscles, where rapid reflexes are required. 
D)  epithelial cells that line animal body cavities. 
E)  skin cells that receive stress. 
A)  animal cells that require a tight structure. 
B)  animal cells that conduct electrical activity, as in the heart. 
C)  muscles, where rapid reflexes are required. 
D)  epithelial cells that line animal body cavities. 
E)  skin cells that receive stress.

Question 17

Refer to the figures below.   The figures show the experimental procedure and results of an investigation.The phospholipids of the cell membrane of a single cell were chemically reacted with a small fluorescent molecule so that there was uniform labeling of the fluorescent molecule across the membrane.The labeled cell was placed under a fluorescent microscope and observed as light from a laser was directed at a small region of the cell for a microsecond.The light bleached (damaged) the fluorescent molecules in that region so that the molecules were no longer able to fluoresce.In the time period following the bleaching event, recovery of fluorescence in the bleached region was observed and graphed.These results support which statement about cell membranes?

Accepted Answer

A)  The cell membrane is composed of a lipid bilayer embedded with proteins. 
B)  Some molecules are transported via simple diffusion through the phospholipid bilayer. 
C)  Some membranes have more proteins than others, and some are lipid-rich. 
D)  Membrane phospholipids interact noncovalently and are in constant flux. 
E)  Phospholipids are oriented in membranes with hydrophobic tails in and hydrophilic heads out. 
A)  The cell membrane is composed of a lipid bilayer embedded with proteins. 
B)  Some molecules are transported via simple diffusion through the phospholipid bilayer. 
C)  Some membranes have more proteins than others, and some are lipid-rich. 
D)  Membrane phospholipids interact noncovalently and are in constant flux. 
E)  Phospholipids are oriented in membranes with hydrophobic tails in and hydrophilic heads out.

Question 18

The sodium-potassium pump of cell membranes is an example of a membrane protein called a(n) _______ that moves two substances in opposite directions across a membrane.

Accepted Answer

The answer of The sodium-potassium pump of cell membranes is...

Question 19

Osmosis, the movement of water though specialized membrane channels, is an example of

Accepted Answer

A)  movement of water by carrier proteins. 
B)  facilitated diffusion. 
C)  active transport. 
D)  secondary active transport. 
E)  simple diffusion. 
A)  movement of water by carrier proteins. 
B)  facilitated diffusion. 
C)  active transport. 
D)  secondary active transport. 
E)  simple diffusion.

Question 20

If equal volumes of differently colored solutions are poured into opposite sides of a shallow pool of water, what will be the result at equilibrium?

Accepted Answer

A)  Each solution will be uniformly distributed in the side of the pool into which it was poured. 
B)  The solutions will be uniformly distributed throughout the pool. 
C)  Each solution will have moved against its concentration gradient. 
D)  The concentration of each solution will be higher in one side of the pool than in the other. 
E)  The solutions will have sunk to the bottom of the pool and remained separate. 
A)  Each solution will be uniformly distributed in the side of the pool into which it was poured. 
B)  The solutions will be uniformly distributed throughout the pool. 
C)  Each solution will have moved against its concentration gradient. 
D)  The concentration of each solution will be higher in one side of the pool than in the other. 
E)  The solutions will have sunk to the bottom of the pool and remained separate.

Exam 6: Cell Membranes

A unicellular organism adapted to living in salt water is placed in a freshwater tank.What is the likely outcome?

The difference between osmosis and diffusion is that

You are studying the effects of different substances on frog heart muscle cells.You treat the cells with a substance that blocks gap junctions.What do you expect will occur?

Refer to the graph below showing the relationship between glucose concentration outside a cell and the rate of facilitated diffusion of glucose across a cell membrane via carrier proteins. Which label on the graph represents saturation of the carrier proteins?

Very high cholesterol levels in those with familial hypercholesterolemia are cause by

Refer to the figures below. Which statement accurately describes the solutions surrounding the three cells shown in the figures, and in which case will there be a net flow of water out of the cell?

Water moves across a cell membrane through a channel protein, whereas glucose moves across a cell membrane via a carrier protein.Which statement provides a valid comparison of these two membrane transport systems?

Refer to the table below. Which statement about biological membranes is supported by these data?

When placed in water, wilted plants regain their leaf turgor because of the

Solution X is hypotonic relative to solution Y if X has a solute concentration that is _______ the solute concentration of Y.

Primary active transport requires energy released from the hydrolysis of _______.

Refer to the figure below. Which statement regarding channel proteins shown in the figure is false?

A biologist wants to compare the integral membrane protein content of cells from mouse liver, pancreas, and intestine.Which experimental procedure should she choose?

Refer to the figure below. The type of cell junction shown is most efficient in

The sodium-potassium pump of cell membranes is an example of a membrane protein called a(n) _______ that moves two substances in opposite directions across a membrane.

Osmosis, the movement of water though specialized membrane channels, is an example of

If equal volumes of differently colored solutions are poured into opposite sides of a shallow pool of water, what will be the result at equilibrium?

Studying Life

Small Molecules and the Chemistry of Life

Proteins, Carbohydrates, and Lipids

Nucleic Acids and the Origin of Life

Cells: the Working Units of Life

Cell Communication and Multicellularity

Energy, Enzymes, and Metabolism

Pathways That Harvest Chemical Energy

Photosynthesis: Energy From Sunlight

The Cell Cycle and Cell Division

Inheritance, Genes, and Chromosomes

Dna and Its Role in Heredity

From Dna to Protein: Gene Expression

Gene Mutation and Molecular Medicine

Regulation of Gene Expression

Genomes

Recombinant Dna and Biotechnology

Mechanisms of Evolution

Reconstructing and Using Phylogenies

Speciation

Evolution of Genes and Genomes

The History of Life on Earth

Bacteria, Archaea, and Viruses

The Origin and Diversification of Eukaryotes

Plants Without Seeds: From Water to Land

The Evolution of Seed Plants

The Evolution and Diversity of Fungi

Animal Origins and the Evolution of Body Plans

Protostome Animals

Deuterostome Animals

The Plant Body

Transport in Plants

Plant Nutrition

Regulation of Plant Growth

Reproduction in Flowering Plants

Plant Responses to Environmental Challenges

Physiology, Homeostasis, and Temperature Regulation

Animal Hormones

Immunology: Animal Defense Systems

Animal Reproduction

Animal Development

Neurons, Glia, and Nervous Systems

Sensory Systems

The Mammalian Nervous System: Structure and Higher Functions

Musculoskeletal Systems

Gas Exchange

Circulatory Systems

Nutrition, Digestion, and Absorption

Salt and Water Balance and Nitrogen Excretion

Animal Behavior

The Physical Environment and Biogeography of Life

Populations

Species Interactions

Communities

Ecosystems

A Changing Biosphere

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