Question 1

Which of the following is True of the evolution of cell membranes?

Accepted Answer

A) Cell membranes have stopped evolving now that they are fluid mosaics. 
B) Cell membranes cannot evolve if proteins do not. 
C) The evolution of cell membranes is driven by the evolution of glycoproteins and glycolipids. 
D) As populations of organisms evolve, different properties of their cell membranes are selected for or against. 
E) An individual organism selects its preferred type of cell membrane for particular functions. 
A) Cell membranes have stopped evolving now that they are fluid mosaics. 
B) Cell membranes cannot evolve if proteins do not. 
C) The evolution of cell membranes is driven by the evolution of glycoproteins and glycolipids. 
D) As populations of organisms evolve, different properties of their cell membranes are selected for or against. 
E) An individual organism selects its preferred type of cell membrane for particular functions.

Question 2

Who was/were the first to propose that cell membranes are phospholipid bilayers?

Accepted Answer

A) H. Davson and J. Danielli 
B) I. Langmuir 
C) C. Overton 
D) S. Singer and G. Nicolson 
E) E. Gorter and F. Grendel 
A) H. Davson and J. Danielli 
B) I. Langmuir 
C) C. Overton 
D) S. Singer and G. Nicolson 
E) E. Gorter and F. Grendel

Question 3

What are the membrane structures that function in active transport?

Accepted Answer

A) peripheral proteins 
B) carbohydrates 
C) cholesterol 
D) cytoskeleton filaments 
E) integral proteins 
A) peripheral proteins 
B) carbohydrates 
C) cholesterol 
D) cytoskeleton filaments 
E) integral proteins

Question 4

Which of the following factors would tend to increase membrane fluidity?

Accepted Answer

A) a greater proportion of unsaturated phospholipids 
B) a greater proportion of saturated phospholipids 
C) a lower temperature 
D) a relatively high protein content in the membrane 
E) a greater proportion of relatively large glycolipids compared with lipids having smaller molecular masses 
A) a greater proportion of unsaturated phospholipids 
B) a greater proportion of saturated phospholipids 
C) a lower temperature 
D) a relatively high protein content in the membrane 
E) a greater proportion of relatively large glycolipids compared with lipids having smaller molecular masses

Question 5

What is the voltage across a membrane called?

Accepted Answer

A) water potential 
B) chemical gradient 
C) membrane potential 
D) osmotic potential 
E) electrochemical gradient 
A) water potential 
B) chemical gradient 
C) membrane potential 
D) osmotic potential 
E) electrochemical gradient

Question 6

Glucose diffuses slowly through artificial phospholipid bilayers. The cells lining the small intestine, however, rapidly move large quantities of glucose from the glucose-rich food into their glucose-poor cytoplasm. Using this information, which transport mechanism is most probably functioning in the intestinal cells?

Accepted Answer

A) simple diffusion 
B) phagocytosis 
C) active transport pumps 
D) exocytosis 
E) facilitated diffusion 
A) simple diffusion 
B) phagocytosis 
C) active transport pumps 
D) exocytosis 
E) facilitated diffusion

Question 7

Read the following information and refer to Figure 7.4 to answer the following questions.
Five dialysis bags, constructed from a semi-permeable membrane that is impermeable to sucrose, were filled with various concentrations of sucrose and then placed in separate beakers containing an initial concentration of 0.6 M sucrose solution. At 10-minute intervals, the bags were massed (weighed) and the percent change in mass of each bag was graphed.

-Which line represents the bag that contained a solution isotonic to the 0.6 molar solution at the beginning of the experiment?

Accepted Answer

The answer of Read the following information and refer to...

Question 8

For the following questions, match the labeled component of the cell membrane (Figure 7.1) with its description.

-microfilament of the cytoskeleton

Accepted Answer

The answer of For the following questions, match the labeled...

Question 9

In what way do the membranes of a eukaryotic cell vary?

Accepted Answer

A) Phospholipids are found only in certain membranes. 
B) Certain proteins are unique to each membrane. 
C) Only certain membranes of the cell are selectively permeable. 
D) Only certain membranes are constructed from amphipathic molecules. 
E) Some membranes have hydrophobic surfaces exposed to the cytoplasm, while others have hydrophilic surfaces facing the cytoplasm. 
A) Phospholipids are found only in certain membranes. 
B) Certain proteins are unique to each membrane. 
C) Only certain membranes of the cell are selectively permeable. 
D) Only certain membranes are constructed from amphipathic molecules. 
E) Some membranes have hydrophobic surfaces exposed to the cytoplasm, while others have hydrophilic surfaces facing the cytoplasm.

Question 10

In which of the following would there be the greatest need for osmoregulation?

Accepted Answer

A) an animal connective tissue cell bathed in isotonic body fluid 
B) a terrestrial animal such as a snake 
C) a red blood cell surrounded by plasma 
D) a lymphocyte before it has been taken back into lymph fluid 
E) a plant being grown hydroponically (in a watery mixture of designated nutrients) 
A) an animal connective tissue cell bathed in isotonic body fluid 
B) a terrestrial animal such as a snake 
C) a red blood cell surrounded by plasma 
D) a lymphocyte before it has been taken back into lymph fluid 
E) a plant being grown hydroponically (in a watery mixture of designated nutrients)

Question 11

The movement of potassium into an animal cell requires

Accepted Answer

A) low cellular concentrations of sodium. 
B) high cellular concentrations of potassium. 
C) an energy source such as ATP or a proton gradient. 
D) a cotransport protein. 
E) a gradient of protons across the plasma membrane. 
A) low cellular concentrations of sodium. 
B) high cellular concentrations of potassium. 
C) an energy source such as ATP or a proton gradient. 
D) a cotransport protein. 
E) a gradient of protons across the plasma membrane.

Question 12

Which of the following membrane activities require energy from ATP hydrolysis?

Accepted Answer

A) facilitated diffusion. 
B) movement of water into a cell 
C) Na⁺ ions moving out of the cell 
D) movement of glucose molecules 
E) movement of water into a paramecium 
A) facilitated diffusion. 
B) movement of water into a cell 
C) Na⁺ ions moving out of the cell 
D) movement of glucose molecules 
E) movement of water into a paramecium

Question 13

For the following questions, match the labeled component of the cell membrane (Figure 7.1) with its description.

-cholesterol

Accepted Answer

The answer of For the following questions, match the labeled...

Question 14

Why are lipids and proteins free to move laterally in membranes?

Accepted Answer

A) The interior of the membrane is filled with liquid water. 
B) There are no covalent bonds between lipid and protein in the membrane. 
C) Hydrophilic portions of the lipids are in the interior of the membrane. 
D) There are only weak hydrophobic interactions in the interior of the membrane. 
E) Molecules such as cellulose can pull them in various directions. 
A) The interior of the membrane is filled with liquid water. 
B) There are no covalent bonds between lipid and protein in the membrane. 
C) Hydrophilic portions of the lipids are in the interior of the membrane. 
D) There are only weak hydrophobic interactions in the interior of the membrane. 
E) Molecules such as cellulose can pull them in various directions.

Question 15

According to the fluid mosaic model of membrane structure, proteins of the membrane are mostly

Accepted Answer

A) spread in a continuous layer over the inner and outer surfaces of the membrane. 
B) confined to the hydrophobic core of the membrane. 
C) embedded in a lipid bilayer. 
D) randomly oriented in the membrane, with no fixed inside-outside polarity. 
E) free to depart from the fluid membrane and dissolve in the surrounding solution. 
A) spread in a continuous layer over the inner and outer surfaces of the membrane. 
B) confined to the hydrophobic core of the membrane. 
C) embedded in a lipid bilayer. 
D) randomly oriented in the membrane, with no fixed inside-outside polarity. 
E) free to depart from the fluid membrane and dissolve in the surrounding solution.

Question 16

Refer to Figure 7.3 to answer the following questions.
The solutions in the arms of a U-tube are separated at the bottom of the tube by a selectively permeable membrane. The membrane is permeable to sodium chloride but not to glucose. Side A is filled with a solution of 0.4 M glucose and 0.5 M sodium chloride (NaCl), and side B is filled with a solution containing 0.8 M glucose and 0.4 M sodium chloride. Initially, the volume in both arms is the same.

-At the beginning of the experiment,
A)side A is hypertonic to side B.
B)side A is hypotonic to side B.
C)side A is isotonic to side B.
D)side A is hypertonic to side B with respect to glucose.
E)side A is hypotonic to side B with respect to sodium chloride.

Accepted Answer

The answer of Refer to Figure 7.3 to answer the...

Question 17

According to the fluid mosaic model of cell membranes, which of the following is a True statement about membrane phospholipids?

Accepted Answer

A) They can move laterally along the plane of the membrane. 
B) They frequently flip-flop from one side of the membrane to the other. 
C) They occur in an uninterrupted bilayer, with membrane proteins restricted to the surface of the membrane. 
D) They are free to depart from the membrane and dissolve in the surrounding solution. 
E) They have hydrophilic tails in the interior of the membrane. 
A) They can move laterally along the plane of the membrane. 
B) They frequently flip-flop from one side of the membrane to the other. 
C) They occur in an uninterrupted bilayer, with membrane proteins restricted to the surface of the membrane. 
D) They are free to depart from the membrane and dissolve in the surrounding solution. 
E) They have hydrophilic tails in the interior of the membrane.

Question 18

Which of the following is True of integral membrane proteins?

Accepted Answer

A) They lack tertiary structure. 
B) They are loosely bound to the surface of the bilayer. 
C) They are usually transmembrane proteins. 
D) They are not mobile within the bilayer. 
E) They serve only a structural role in membranes. 
A) They lack tertiary structure. 
B) They are loosely bound to the surface of the bilayer. 
C) They are usually transmembrane proteins. 
D) They are not mobile within the bilayer. 
E) They serve only a structural role in membranes.

Question 19

Which of the following processes includes all others?

Accepted Answer

A) osmosis 
B) diffusion of a solute across a membrane 
C) facilitated diffusion 
D) passive transport 
E) transport of an ion down its electrochemical gradient 
A) osmosis 
B) diffusion of a solute across a membrane 
C) facilitated diffusion 
D) passive transport 
E) transport of an ion down its electrochemical gradient

Question 20

Ions diffuse across membranes down their

Accepted Answer

A) chemical gradients. 
B) concentration gradients. 
C) electrical gradients. 
D) electrochemical gradients. 
E) A and B are correct. 
A) chemical gradients. 
B) concentration gradients. 
C) electrical gradients. 
D) electrochemical gradients. 
E) A and B are correct.

Exam 7: Membrane Structure and Function

Which of the following is True of the evolution of cell membranes?

Who was/were the first to propose that cell membranes are phospholipid bilayers?

What are the membrane structures that function in active transport?

Which of the following factors would tend to increase membrane fluidity?

What is the voltage across a membrane called?

For the following questions, match the labeled component of the cell membrane (Figure 7.1) with its description. -microfilament of the cytoskeleton

In what way do the membranes of a eukaryotic cell vary?

In which of the following would there be the greatest need for osmoregulation?

The movement of potassium into an animal cell requires

Which of the following membrane activities require energy from ATP hydrolysis?

For the following questions, match the labeled component of the cell membrane (Figure 7.1) with its description. -cholesterol

Why are lipids and proteins free to move laterally in membranes?

According to the fluid mosaic model of membrane structure, proteins of the membrane are mostly

According to the fluid mosaic model of cell membranes, which of the following is a True statement about membrane phospholipids?

Which of the following is True of integral membrane proteins?

Which of the following processes includes all others?

Ions diffuse across membranes down their

Introduction: Themes in the Study of Life

The Chemical Context of Life

Water and the Fitness of the Environment

Carbon and the Molecular Diversity of Life

The Structure and Function of Large Biological Molecules

A Tour of the Cell

An Introduction to Metabolism

Cellular Respiration: Harvesting Chemical Energy

Photosynthesis

Cell Communication

The Cell Cycle

Meiosis and Sexual Life Cycles

Mendel and the Gene Idea

The Chromosomal Basis of Inheritance

The Molecular Basis of Inheritance

From Gene to Protein

Control of Gene Expression

Viruses

Biotechnology

Genomes and Their Evolution

Descent With Modification: a Darwinian View of Life

The Evolution of Populations

The Origin of Species

The History of Life on Earth

Phylogeny and the Tree of Life

Bacteria and Archaea

Protists

Plant Diversity I: How Plants Colonized Land

Plant Diversity Ii: the Evolution of Seed Plants

Fungi

An Introduction to Animal Diversity

Invertebrates

Vertebrates

Plant Structure, Growth, and Development

Transport in Vascular Plants

Soil and Plant Nutrition

Angiosperm Reproduction and Biotechnology

Plant Responses to Internal and External Signals

Basic Principles of Animal Form and Function

Animal Nutrition

Circulation and Gas Exchange

The Immune System

Osmoregulation and Excretion

Hormones and the Endocrine System

Animal Reproduction

Animal Development

Neurons, Synapses, and Signaling

Nervous Systems

Sensory and Motor Mechanisms

Animal Behavior

An Introduction to Ecology and the Biosphere

Population Ecology

Community Ecology

Ecosystems

Conservation Biology and Restoration Ecology

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