Question 1

Plant cells transport sucrose across the vacuole membrane against its concentration gradient by a process known as

Accepted Answer

A)  simple diffusion. 
B)  active transport. 
C)  passive transport. 
D)  facilitated diffusion. 
E)  cellular respiration. 
A)  simple diffusion. 
B)  active transport. 
C)  passive transport. 
D)  facilitated diffusion. 
E)  cellular respiration.

Question 2

The electric signal for a contraction passes rapidly from one muscle cell to the next by way of

Accepted Answer

A)  tight junctions. 
B)  desmosomes. 
C)  gap junctions. 
D)  integral membrane proteins. 
E)  freeze-fractures. 
A)  tight junctions. 
B)  desmosomes. 
C)  gap junctions. 
D)  integral membrane proteins. 
E)  freeze-fractures.

Question 3

Lipids can move in a _______ direction, although they seldom move across the bilayers of a biological membrane.

Accepted Answer

The answer of Lipids can move in a _______ direction,...

Question 4

Phagocytosis, pinocytosis, and receptor-mediated endocytosis all involve

Accepted Answer

A)  the intake of large particles. 
B)  invagination of the plasma membrane. 
C)  the export of macromolecules. 
D)  the presence of receptor proteins. 
E)  the intake of fluids by the cell. 
A)  the intake of large particles. 
B)  invagination of the plasma membrane. 
C)  the export of macromolecules. 
D)  the presence of receptor proteins. 
E)  the intake of fluids by the cell.

Question 5

The plasma membrane of animals contains carbohydrates

Accepted Answer

A)  on the inner side of the membrane, facing the cytosol. 
B)  on the outer side of the membrane, protruding into the environment. 
C)  on both sides of the membrane. 
D)  on neither side of the membrane. 
E)  within the membrane. 
A)  on the inner side of the membrane, facing the cytosol. 
B)  on the outer side of the membrane, protruding into the environment. 
C)  on both sides of the membrane. 
D)  on neither side of the membrane. 
E)  within the membrane.

Question 6

If a shallow pan is filled with water, a drop of red ink is placed in one end of the pan, and a drop of green ink is placed in the other end, which of the following will be true at equilibrium?

Accepted Answer

A)  The red ink will be uniformly distributed in one half of the pan, and the green ink will be uniformly distributed in the other half of the pan. 
B)  The red and green inks will be uniformly distributed throughout the pan. 
C)  Each ink will move down its concentration gradient. 
D)  The concentration of each ink will be higher at one end of the pan than at the other end. 
E)  No predictions can be made without knowing the molecular weights of the pigment molecules. 
A)  The red ink will be uniformly distributed in one half of the pan, and the green ink will be uniformly distributed in the other half of the pan. 
B)  The red and green inks will be uniformly distributed throughout the pan. 
C)  Each ink will move down its concentration gradient. 
D)  The concentration of each ink will be higher at one end of the pan than at the other end. 
E)  No predictions can be made without knowing the molecular weights of the pigment molecules.

Question 7

When plant cells are placed in a hypotonic solution, water enters the cells and exerts pressure against the cell wall. This force is called _______ pressure.

Accepted Answer

The answer of When plant cells are placed in a...

Question 8

When placed in water, wilted plants lose their limpness because of

Accepted Answer

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

Question 9

The plasma membranes of winter wheat are able to remain fluid when it is extremely cold by

Accepted Answer

A)  increasing the number of cholesterol molecules present. 
B)  closing protein channels. 
C)  decreasing the number of hydrophobic proteins present. 
D)  replacing saturated fatty acids with unsaturated fatty acids. 
E)  using fatty acids with longer tails. 
A)  increasing the number of cholesterol molecules present. 
B)  closing protein channels. 
C)  decreasing the number of hydrophobic proteins present. 
D)  replacing saturated fatty acids with unsaturated fatty acids. 
E)  using fatty acids with longer tails.

Question 10

Active transport usually moves molecules

Accepted Answer

A)  in the same direction as diffusion moves them. 
B)  in a direction opposite to the one in which diffusion moves them. 
C)  in a direction that tends to bring about equilibrium. 
D)  toward higher pH. 
E)  toward higher osmotic potential. 
A)  in the same direction as diffusion moves them. 
B)  in a direction opposite to the one in which diffusion moves them. 
C)  in a direction that tends to bring about equilibrium. 
D)  toward higher pH. 
E)  toward higher osmotic potential.

Question 11

Phospholipids spontaneously form bilayer structures, but oils form small droplets. Why do oils not form bilayers?

Accepted Answer

A)  Oils are not as hydrophobic as phospholipids. 
B)  The fatty acids in oils preclude bilayer formation. 
C)  Oils are energy reserves of cells. 
D)  Oils do not have the polar head group that phospholipids have. 
E)  Oils and water do not mix. 
A)  Oils are not as hydrophobic as phospholipids. 
B)  The fatty acids in oils preclude bilayer formation. 
C)  Oils are energy reserves of cells. 
D)  Oils do not have the polar head group that phospholipids have. 
E)  Oils and water do not mix.

Question 12

A voltage difference is maintained across the plasma membrane. This voltage difference

Accepted Answer

A)  is positive on the inside of the cell relative to the outside. 
B)  does not require energy to generate and maintain. 
C)  arises because the sodium-potassium pump pumps 2 Na+ in and 3 K+ out during one catalytic cycle. 
D)  arises because the sodium-potassium pump pumps 2 K+ in and 3 Na+ out during one catalytic cycle. 
E)  arises from secondary active transport. 
A)  is positive on the inside of the cell relative to the outside. 
B)  does not require energy to generate and maintain. 
C)  arises because the sodium-potassium pump pumps 2 Na+ in and 3 K+ out during one catalytic cycle. 
D)  arises because the sodium-potassium pump pumps 2 K+ in and 3 Na+ out during one catalytic cycle. 
E)  arises from secondary active transport.

Question 13

Biological membranes are composed of

Accepted Answer

A)  nucleotides and nucleosides. 
B)  enzymes, electron acceptors, and electron donors. 
C)  fatty acids. 
D)  monosaccharides. 
E)  lipids, proteins, and carbohydrates. 
A)  nucleotides and nucleosides. 
B)  enzymes, electron acceptors, and electron donors. 
C)  fatty acids. 
D)  monosaccharides. 
E)  lipids, proteins, and carbohydrates.

Question 14

Which of the following does not affect the rate of diffusion of a substance?

Accepted Answer

A)  Temperature of the solution 
B)  Concentration gradient 
C)  Distance traveled 
D)  Presence of other substances in the solution 
E)  Molecular diameter of the diffusing material 
A)  Temperature of the solution 
B)  Concentration gradient 
C)  Distance traveled 
D)  Presence of other substances in the solution 
E)  Molecular diameter of the diffusing material

Question 15

Which of the following contributes to differences in the two sides of the cell membrane?

Accepted Answer

A)  Differences in peripheral proteins 
B)  Different domains expressed on the ends of integral proteins 
C)  Differences in phospholipid types 
D)  Differences in the carbohydrates attached to membrane proteins 
E)  All of the above 
A)  Differences in peripheral proteins 
B)  Different domains expressed on the ends of integral proteins 
C)  Differences in phospholipid types 
D)  Differences in the carbohydrates attached to membrane proteins 
E)  All of the above

Question 16

Single-celled animals, such as amoebas, engulf entire cells for food. This manner of "eating" is called

Accepted Answer

A)  exocytosis. 
B)  endocytosis. 
C)  facilitative transport. 
D)  active transport. 
E)  osmosis. 
A)  exocytosis. 
B)  endocytosis. 
C)  facilitative transport. 
D)  active transport. 
E)  osmosis.

Question 17

Which of the following statements about diffusion is false?

Accepted Answer

A)  Diffusion depends on the intrinsic kinetic energy of molecules. 
B)  Diffusion continues until the concentrations are in equilibrium. 
C)  In diffusion, molecules move from areas of greater concentration to areas of lesser concentration. 
D)  Diffusion is a random process. 
E)  Simple diffusion depends upon specific carrier proteins. 
A)  Diffusion depends on the intrinsic kinetic energy of molecules. 
B)  Diffusion continues until the concentrations are in equilibrium. 
C)  In diffusion, molecules move from areas of greater concentration to areas of lesser concentration. 
D)  Diffusion is a random process. 
E)  Simple diffusion depends upon specific carrier proteins.

Question 18

Which of the following molecules do you think would diffuse across a phospholipid bilayer fastest, assuming that there are no proteins associated with the bilayer. (Hint: keep in mind the nature of the interior of the bilayer).

Accepted Answer

A)  H2O 
B)  NH4+ 
C)  CH3COO- 
D)  NH3 
E)  Na+ 
A)  H2O 
B)  NH4+ 
C)  CH3COO- 
D)  NH3 
E)  Na+

Question 19

Which of the following is not a function of exocytosis?

Accepted Answer

A)  Neurotransmitter secretion 
B)  Secretion of digestive enzymes in the pancreas 
C)  Lysosome formation 
D)  Secretion of cell wall materials in plants 
E)  Secretion of waste products 
A)  Neurotransmitter secretion 
B)  Secretion of digestive enzymes in the pancreas 
C)  Lysosome formation 
D)  Secretion of cell wall materials in plants 
E)  Secretion of waste products

Question 20

How can water, a polar molecule, cross biological membranes rapidly?

Accepted Answer

A)  It is small enough to slip through the hydrophobic part of the bilayer. 
B)  The diffusion of water is facilitated by aquaporins. 
C)  Water is actively pumped across the membrane. 
D)  Water enters cells together with ions. 
E)  Both b and d 
A)  It is small enough to slip through the hydrophobic part of the bilayer. 
B)  The diffusion of water is facilitated by aquaporins. 
C)  Water is actively pumped across the membrane. 
D)  Water enters cells together with ions. 
E)  Both b and d

Exam 6: Cell Membranes

Plant cells transport sucrose across the vacuole membrane against its concentration gradient by a process known as

The electric signal for a contraction passes rapidly from one muscle cell to the next by way of

Lipids can move in a _______ direction, although they seldom move across the bilayers of a biological membrane.

Phagocytosis, pinocytosis, and receptor-mediated endocytosis all involve

The plasma membrane of animals contains carbohydrates

If a shallow pan is filled with water, a drop of red ink is placed in one end of the pan, and a drop of green ink is placed in the other end, which of the following will be true at equilibrium?

When plant cells are placed in a hypotonic solution, water enters the cells and exerts pressure against the cell wall. This force is called _______ pressure.

When placed in water, wilted plants lose their limpness because of

The plasma membranes of winter wheat are able to remain fluid when it is extremely cold by

Active transport usually moves molecules

Phospholipids spontaneously form bilayer structures, but oils form small droplets. Why do oils not form bilayers?

A voltage difference is maintained across the plasma membrane. This voltage difference

Biological membranes are composed of

Which of the following does not affect the rate of diffusion of a substance?

Which of the following contributes to differences in the two sides of the cell membrane?

Single-celled animals, such as amoebas, engulf entire cells for food. This manner of "eating" is called

Which of the following statements about diffusion is false?

Which of the following molecules do you think would diffuse across a phospholipid bilayer fastest, assuming that there are no proteins associated with the bilayer. (Hint: keep in mind the nature of the interior of the bilayer).

Which of the following is not a function of exocytosis?

How can water, a polar molecule, cross biological membranes rapidly?

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

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