Question 1

Cell membranes have distinct inside and outside faces. Which of the following statements is the most likely explanation for the membrane's asymmetrical nature?

Accepted Answer

A)  Since the cell membrane forms a border between one cell and another in tightly packed tissues such as epithelium, the membrane must be asymmetrical. 
B)  Since cell membranes communicate signals from one organism to another, the cell membranes must be asymmetrical. 
C)  The two sides of a cell membrane face different environments and carry out different functions. 
D)  Proteins only function on the cytoplasmic side of the cell membrane, which results in the membrane's asymmetrical nature. 
A)  Since the cell membrane forms a border between one cell and another in tightly packed tissues such as epithelium, the membrane must be asymmetrical. 
B)  Since cell membranes communicate signals from one organism to another, the cell membranes must be asymmetrical. 
C)  The two sides of a cell membrane face different environments and carry out different functions. 
D)  Proteins only function on the cytoplasmic side of the cell membrane, which results in the membrane's asymmetrical nature.

Question 2

Which of the following processes includes all the others?

Accepted Answer

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

Question 3

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. 
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.

Question 4

Which of the following structures would decrease the electrochemical gradient across a membrane?

Accepted Answer

A)  an aquaporin 
B)  a proton pump 
C)  a potassium channel 
D)  both a proton pump and a sodium channel 
A)  an aquaporin 
B)  a proton pump 
C)  a potassium channel 
D)  both a proton pump and a sodium channel

Question 5

A patient was involved a serious accident and lost a large quantity of blood. In an attempt to replenish body fluids, distilled water-equal to the volume of blood lost-is added to the blood directly via one of his veins. What will be the most probable result of this transfusion?

Accepted Answer

A)  The patient's red blood cells will shrivel up because the blood has become hypotonic compared to the cells. 
B)  The patient's red blood cells will swell and possibly burst because the blood has become hypotonic compared to the cells. 
C)  The patient's red blood cells will shrivel up because the blood has become hypertonic compared to the cells. 
D)  The patient's red blood cells will burst because the blood has become hypertonic compared to the cells. 
A)  The patient's red blood cells will shrivel up because the blood has become hypotonic compared to the cells. 
B)  The patient's red blood cells will swell and possibly burst because the blood has become hypotonic compared to the cells. 
C)  The patient's red blood cells will shrivel up because the blood has become hypertonic compared to the cells. 
D)  The patient's red blood cells will burst because the blood has become hypertonic compared to the cells.

Question 6

Which of the following 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 7

A research team is working on the design of a new drug for the treatment of lung cancer. To be most effective, this drug must specifically enter the cytoplasm of lung cells while not entering the cells of other tissues. Which of the following characteristics would likely enhance the specificity of this drug?

Accepted Answer

A)  the relative hydrophobicity of the drug molecule 
B)  phospholipid composition of lung cell plasma membranes 
C)  specificity of the drug molecule for binding to the extracellular matrix of lung cells 
D)  similarity of the drug molecule to other molecules normally transported lung cells 
A)  the relative hydrophobicity of the drug molecule 
B)  phospholipid composition of lung cell plasma membranes 
C)  specificity of the drug molecule for binding to the extracellular matrix of lung cells 
D)  similarity of the drug molecule to other molecules normally transported lung cells

Question 8

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.

Exam 7: Membrane Structure and Function

Cell membranes have distinct inside and outside faces. Which of the following statements is the most likely explanation for the membrane's asymmetrical nature?

Which of the following processes includes all the others?

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

Which of the following structures would decrease the electrochemical gradient across a membrane?

A patient was involved a serious accident and lost a large quantity of blood. In an attempt to replenish body fluids, distilled water-equal to the volume of blood lost-is added to the blood directly via one of his veins. What will be the most probable result of this transfusion?

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

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?

Evolution, the Themes of Biology, and Scientific Inquiry

The Chemical Context of Life

Water and Life

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 and Fermentation

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

Gene Expression: From Gene to Protein

Regulation of Gene Expression

Viruses

DNA Tools and 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 Overview of Animal Diversity

An Introduction to Invertebrates

The Origin and Evolution of Vertebrates

Vascular Plant Structure, Growth, and Development

Resource Acquisition and 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 and Restoration Ecology

Conservation Biology and Global Change

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