Question 1

Which of the following statements best describes a characteristic feature of integral membrane proteins?

Accepted Answer

A)  They are hydrophilic. 
B)  They are hydrophobic. 
C)  They are amphipathic, with at least one hydrophobic region. 
D)  They are localized to the interior surface of the membrane. 
A)  They are hydrophilic. 
B)  They are hydrophobic. 
C)  They are amphipathic, with at least one hydrophobic region. 
D)  They are localized to the interior surface of the membrane.

Question 2

Which of the following types of molecules are least likely to diffuse through the phospholipid bilayer of a cell membrane?

Accepted Answer

A)  large hydrophobic molecules 
B)  small hydrophobic molecules 
C)  carbon dioxide 
D)  small ions 
A)  large hydrophobic molecules 
B)  small hydrophobic molecules 
C)  carbon dioxide 
D)  small ions

Question 3

Celery stalks that are immersed in fresh water for several hours become stiff. Which of the following statements best explains the observation that similar stalks left in a 0.15 M salt solution become limp?

Accepted Answer

A)  The fresh water and the salt solution are both hypertonic to the cells of the celery stalks. 
B)  The fresh water is hypotonic and the salt solution is hypertonic to the cells of the celery stalks 
C)  The fresh water is hypertonic and the salt solution is hypotonic to the cells of the celery stalks 
D)  The fresh water is isotonic and the salt solution is hypertonic to the cells of the celery stalks 
A)  The fresh water and the salt solution are both hypertonic to the cells of the celery stalks. 
B)  The fresh water is hypotonic and the salt solution is hypertonic to the cells of the celery stalks 
C)  The fresh water is hypertonic and the salt solution is hypotonic to the cells of the celery stalks 
D)  The fresh water is isotonic and the salt solution is hypertonic to the cells of the celery stalks

Question 4

A phospholipid bilayer with equal amounts of saturated and unsaturated fatty acids displays a specific permeability to glucose. What effect will increasing the proportion of unsaturated fatty acids in the bilayer have on the membrane's permeability to glucose?

Accepted Answer

A)  Permeability to glucose will increase. 
B)  Permeability to glucose will decrease. 
C)  Permeability to glucose will stay the same. 
D)  Permeability will decrease initially then increase as the bilayer fills with glucose. 
A)  Permeability to glucose will increase. 
B)  Permeability to glucose will decrease. 
C)  Permeability to glucose will stay the same. 
D)  Permeability will decrease initially then increase as the bilayer fills with glucose.

Question 5

The solutions in the two arms of a 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 statements best describes the relationship between the solutions on both sides of the U-tube?

Accepted Answer

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 more turgid than side B 
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 more turgid than side B

Question 6

Which of the following statements best describes the normal tonicity conditions for typical plant and animal cells in their native environments?

Accepted Answer

A)  The animal cell is in a hypotonic solution, and the plant cell is in an isotonic solution. 
B)  The animal cell is in an isotonic solution, and the plant cell is in a hypertonic solution. 
C)  The animal cell is in a hypertonic solution, and the plant cell is in an isotonic solution. 
D)  The animal cell is in an isotonic solution, and the plant cell is in a hypotonic solution. 
A)  The animal cell is in a hypotonic solution, and the plant cell is in an isotonic solution. 
B)  The animal cell is in an isotonic solution, and the plant cell is in a hypertonic solution. 
C)  The animal cell is in a hypertonic solution, and the plant cell is in an isotonic solution. 
D)  The animal cell is in an isotonic solution, and the plant cell is in a hypotonic solution.

Question 7

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 
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

Exam 8: Cell Membranes

Which of the following statements best describes a characteristic feature of integral membrane proteins?

Which of the following types of molecules are least likely to diffuse through the phospholipid bilayer of a cell membrane?

Celery stalks that are immersed in fresh water for several hours become stiff. Which of the following statements best explains the observation that similar stalks left in a 0.15 M salt solution become limp?

A phospholipid bilayer with equal amounts of saturated and unsaturated fatty acids displays a specific permeability to glucose. What effect will increasing the proportion of unsaturated fatty acids in the bilayer have on the membrane's permeability to glucose?

Which of the following statements best describes the normal tonicity conditions for typical plant and animal cells in their native environments?

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

Biology and Its Themes

Atoms and Molecules

The Chemistry of Water

Carbon: the Basis of Molecular Diversity

Biological Macromolecules and Lipids

Energy and Life

Cell Structure and Function

Cellular Signaling

Cell Respiration

Photosynthetic Processes

Mitosis

Sexual Life Cycles and Meiosis

Mendelian Genetics

Linkage and Chromosomes

Nucleic Acids and Inheritance

Expression of Genes

Control of Gene Expression

Dna Technology

The Evolution of Genomes

How Evolution Works

Phylogenetic Reconstruction

Microevolution

Species and Speciation

Macroevolution

Introduction to Viruses

Prokaryotes

The Origin and Evolution of Eukaryotes

Nonvascular and Seedless Vascular Plants

Seed Plants

Introduction to Fungi

An Introduction to Animal Diversity

Invertebrates

Vertebrates

Plant Structure and Growth

Transport in Vascular Plants

Plant Nutrition

Reproduction of Flowering Plants

Plant Signals and Behavior

The Animal Body

Chemical Signals in Animals

Animal Digestive Systems

Animal Transport Systems

Animal Excretory Systems

Animal Reproductive Systems

Development in Animals

Animal Defenses Against Infection

Electrical Signals in Animals

Neural Regulation in Animals

Sensation and Movement in Animals

An Overview of Ecology

Behavioral Ecology

Populations and Life History Traits

Biodiversity and Communities

Energy Flow and Chemical Cycling in Ecosystems

Conservation and Global Ecology

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