Question 1

What will happen if a red blood cell with an internal salt concentration of about 0.85 percent is placed in a saline solution that is 4 percent?

Accepted Answer

A)  The red blood cell will lose water and shrivel. 
B)  The red blood cell will gain water and burst. 
C)  The turgor pressure in the cell will increase greatly. 
D)  The turgor pressure in the cell will decrease greatly. 
E)  The cell will remain unchanged. 
A)  The red blood cell will lose water and shrivel. 
B)  The red blood cell will gain water and burst. 
C)  The turgor pressure in the cell will increase greatly. 
D)  The turgor pressure in the cell will decrease greatly. 
E)  The cell will remain unchanged.

Question 2

A protein that forms an ion channel through a membrane is most likely to be

Accepted Answer

A)  a peripheral protein. 
B)  a transmembrane protein. 
C)  a phospholipid. 
D)  an enzyme. 
E)  entirely outside the phospholipid bilayer. 
A)  a peripheral protein. 
B)  a transmembrane protein. 
C)  a phospholipid. 
D)  an enzyme. 
E)  entirely outside the phospholipid bilayer.

Question 3

When a mouse cell and a human cell are fused, the membrane proteins of the two cells become uniformly distributed over the surface of the hybrid cell. This occurs because

Accepted Answer

A)  many proteins can move around within the bilayer. 
B)  all proteins are anchored within the membrane. 
C)  proteins are asymmetrically distributed within the membrane. 
D)  all proteins in the plasma membrane are peripheral. 
E)  different membranes contain different proteins. 
A)  many proteins can move around within the bilayer. 
B)  all proteins are anchored within the membrane. 
C)  proteins are asymmetrically distributed within the membrane. 
D)  all proteins in the plasma membrane are peripheral. 
E)  different membranes contain different proteins.

Question 4

In a hypothetical study, cells are placed in a solution of glucose in which the concentration of glucose is gradually increased. At first, the rate at which glucose enters the cells is found to increase as the concentration of the glucose solution is increased. But when the glucose concentration of the solution is increased above 10 M, the rate no longer increases. Which of the following is the likely mechanism for glucose transport into these cells?

Accepted Answer

A)  Facilitated diffusion via a carrier protein 
B)  Facilitated diffusion via a channel protein 
C)  Pinocytosis 
D)  Secondary active transport 
E)  A symporter 
A)  Facilitated diffusion via a carrier protein 
B)  Facilitated diffusion via a channel protein 
C)  Pinocytosis 
D)  Secondary active transport 
E)  A symporter

Question 5

In biological membranes, the phospholipids are arranged in a _______, with the _______.

Accepted Answer

A)  bilayer; fatty acids pointing toward each other 
B)  bilayer; fatty acids facing outward 
C)  single layer; fatty acids facing the interior of the cell 
D)  single layer; phosphorus-containing region facing the interior of the cell 
E)  bilayer; phosphorus groups in the interior of the membrane 
A)  bilayer; fatty acids pointing toward each other 
B)  bilayer; fatty acids facing outward 
C)  single layer; fatty acids facing the interior of the cell 
D)  single layer; phosphorus-containing region facing the interior of the cell 
E)  bilayer; phosphorus groups in the interior of the membrane

Question 6

Channel proteins allow ions that would not normally pass through the cell membrane to pass through via the channel. What property of the channel proteins is responsible for this?

Accepted Answer

A)  A pore of polar amino acid groups 
B)  A pore of hydrophobic amino acid groups 
C)  A pore of Ca2+ 
D)  All of the above 
E)  None of the above 
A)  A pore of polar amino acid groups 
B)  A pore of hydrophobic amino acid groups 
C)  A pore of Ca2+ 
D)  All of the above 
E)  None of the above

Question 7

You are monitoring the diffusion of a molecule across a membrane. Which of the following will result in the fastest rate of diffusion?

Accepted Answer

A)  An internal concentration of 5 percent and an external concentration of 60 percent 
B)  An internal concentration of 60 percent and an external concentration of 5 percent 
C)  An internal concentration of 35 percent and an external concentration of 40 percent 
D)  An internal concentration of 50 percent and an external concentration of 50 percent 
E)  Both a and b 
A)  An internal concentration of 5 percent and an external concentration of 60 percent 
B)  An internal concentration of 60 percent and an external concentration of 5 percent 
C)  An internal concentration of 35 percent and an external concentration of 40 percent 
D)  An internal concentration of 50 percent and an external concentration of 50 percent 
E)  Both a and b

Question 8

Amino acids enter cells against their concentration gradients by means of

Accepted Answer

A)  simple diffusion. 
B)  facilitated diffusion. 
C)  primary active transport. 
D)  secondary active transport. 
E)  osmosis. 
A)  simple diffusion. 
B)  facilitated diffusion. 
C)  primary active transport. 
D)  secondary active transport. 
E)  osmosis.

Question 9

Which of the following processes does not involve the uptake of materials into the cell?

Accepted Answer

A)  Exocytosis 
B)  Pinocytosis 
C)  Endocytosis 
D)  Receptor-mediated endocytosis 
E)  Phagocytsis 
A)  Exocytosis 
B)  Pinocytosis 
C)  Endocytosis 
D)  Receptor-mediated endocytosis 
E)  Phagocytsis

Question 10

Which of the following statements about channel proteins is true?

Accepted Answer

A)  They have a central pore of polar amino acids and water. 
B)  They are anchored in the hydrophobic bilayer of the plasma membrane. 
C)  They are surrounded by nonpolar amino acids. 
D)  They are usually gated. 
E)  All of the above 
A)  They have a central pore of polar amino acids and water. 
B)  They are anchored in the hydrophobic bilayer of the plasma membrane. 
C)  They are surrounded by nonpolar amino acids. 
D)  They are usually gated. 
E)  All of the above

Question 11

Many cells have a sodium-potassium pump. In order to function, sodium-potassium pumps require

Accepted Answer

A)  ATP. 
B)  a channel protein. 
C)  no concentration gradient. 
D)  ADP. 
E)  All of the above 
A)  ATP. 
B)  a channel protein. 
C)  no concentration gradient. 
D)  ADP. 
E)  All of the above

Question 12

Which statement about animal cell junctions is not true?

Accepted Answer

A)  Tight junctions are barriers to the passage of molecules between cells. 
B)  Desmosomes allow cells to adhere firmly to one another. 
C)  Gap junctions block communication between adjacent cells. 
D)  Connexons are made of protein. 
E)  The fibers associated with desmosomes are made of protein. 
A)  Tight junctions are barriers to the passage of molecules between cells. 
B)  Desmosomes allow cells to adhere firmly to one another. 
C)  Gap junctions block communication between adjacent cells. 
D)  Connexons are made of protein. 
E)  The fibers associated with desmosomes are made of protein.

Question 13

The sodium-potassium pump (or Na+-K+ pump)

Accepted Answer

A)  is present in endomembranes. 
B)  is an example of a secondary active transporter. 
C)  results in the formation of a membrane potential across the plasma membrane. 
D)  carries out facilitated diffusion. 
E)  is a symporter. 
A)  is present in endomembranes. 
B)  is an example of a secondary active transporter. 
C)  results in the formation of a membrane potential across the plasma membrane. 
D)  carries out facilitated diffusion. 
E)  is a symporter.

Question 14

Which of the following molecules is the most likely to diffuse across a cell membrane?

Accepted Answer

A)  Glucose 
B)  Na+ 
C)  A steroid 
D)  A common amino acid 
E)  Cl- 
A)  Glucose 
B)  Na+ 
C)  A steroid 
D)  A common amino acid 
E)  Cl-

Question 15

In facilitated diffusion, the diffusion rate of a specific molecule across a membrane does not continue to increase as the concentration difference of the molecule across the membrane increases. This is the case because

Accepted Answer

A)  facilitated diffusion requires the use of ATP. 
B)  as the concentration difference increases, molecules interfere with one another. 
C)  the carrier proteins are saturated. 
D)  the transport protein must be of the channel type. 
E)  the diffusion constant depends on the concentration difference. 
A)  facilitated diffusion requires the use of ATP. 
B)  as the concentration difference increases, molecules interfere with one another. 
C)  the carrier proteins are saturated. 
D)  the transport protein must be of the channel type. 
E)  the diffusion constant depends on the concentration difference.

Question 16

Cells have the ability to take in large molecules by endocytosis and secrete them to the environment by exocytosis. Describe each process and explain why both are important for the cell.

Accepted Answer

Cells take up large particles, foreign c

Question 17

Osmosis is a specific form of

Accepted Answer

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

Question 18

Osmosis is

Accepted Answer

A)  the diffusion of water across membranes. 
B)  the active transport of water across membranes. 
C)  unidirectional diffusion of water across membranes. 
D)  unaffected by solute concentrations inside cells. 
E)  a process that requires energy. 
A)  the diffusion of water across membranes. 
B)  the active transport of water across membranes. 
C)  unidirectional diffusion of water across membranes. 
D)  unaffected by solute concentrations inside cells. 
E)  a process that requires energy.

Question 19

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 concentrations 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 molecules. 
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 concentrations 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 molecules. 
E)  the process of osmosis varies according to the kinds of particles present.

Question 20

Which statement about ion channels is not true?

Accepted Answer

A)  They form pores in the membrane. 
B)  They are proteins. 
C)  All ions pass through the same type of channel. 
D)  Movement through them is from regions of high concentration to regions of low concentration. 
E)  Movement through them is by simple diffusion. 
A)  They form pores in the membrane. 
B)  They are proteins. 
C)  All ions pass through the same type of channel. 
D)  Movement through them is from regions of high concentration to regions of low concentration. 
E)  Movement through them is by simple diffusion.

Exam 6: Cell Membranes

What will happen if a red blood cell with an internal salt concentration of about 0.85 percent is placed in a saline solution that is 4 percent?

A protein that forms an ion channel through a membrane is most likely to be

When a mouse cell and a human cell are fused, the membrane proteins of the two cells become uniformly distributed over the surface of the hybrid cell. This occurs because

In biological membranes, the phospholipids are arranged in a _______, with the _______.

Channel proteins allow ions that would not normally pass through the cell membrane to pass through via the channel. What property of the channel proteins is responsible for this?

You are monitoring the diffusion of a molecule across a membrane. Which of the following will result in the fastest rate of diffusion?

Amino acids enter cells against their concentration gradients by means of

Which of the following processes does not involve the uptake of materials into the cell?

Which of the following statements about channel proteins is true?

Many cells have a sodium-potassium pump. In order to function, sodium-potassium pumps require

Which statement about animal cell junctions is not true?

The sodium-potassium pump (or Na+-K+ pump)

Which of the following molecules is the most likely to diffuse across a cell membrane?

In facilitated diffusion, the diffusion rate of a specific molecule across a membrane does not continue to increase as the concentration difference of the molecule across the membrane increases. This is the case because

Cells have the ability to take in large molecules by endocytosis and secrete them to the environment by exocytosis. Describe each process and explain why both are important for the cell.

Osmosis is a specific form of

Osmosis is

The difference between osmosis and diffusion is that

Which statement about ion channels is not true?

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 Signaling and Communication

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

Recombinent Dna and Biotechnology

Differential Gene Expression in Development

Development and Evolutionary Change

Evidence and Mechanisms of Evolution

Reconstructing and Using Phylogenies

Species and Their Formation

Evolution of Genes and Genomes

The History of Life on Earth

Bacteria and Archaea: the Prokaryotic Domains

The Origin and Diversification of Eukaryotes

Plants Without Seeds: From Water to Land

The Evolution of Seed Plants

Fungi: Recyclers, Pathogens, Parasites, and Plant Partners

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 and Nervous Systems

Sensory Systems

The Mammalian Nervous System: Structure and Higher Function

Musculoskeletal Systems

Gas Exchange in Animals

Circulatory Systems

Nutrition, Digestion, and Absorption

Salt and Water Balance and Nitrogen

Animal Behavior

Ecology and the Distribution of Life

Population Ecology

Species Interaction and Coevolution

Community Ecology

Ecosystems and Global Ecology

Conservation Biology

Filters

In biological membranes, the phospholipids are arranged in a _, with the _.

The sodium-potassium pump (or Na⁺-K⁺pump)