Question 1

When a cell is in equilibrium with its environment,which of the following occurs for substances that can diffuse through the cell?

Accepted Answer

A) There is random movement of substances into and out of the cell. 
B) There is directed movement of substances into and out of the cell. 
C) There is no movement of substances into and out of the cell. 
D) All movement of molecules is directed by active transport. 
E) Molecules move up their concentration gradient. 
A) There is random movement of substances into and out of the cell. 
B) There is directed movement of substances into and out of the cell. 
C) There is no movement of substances into and out of the cell. 
D) All movement of molecules is directed by active transport. 
E) Molecules move up their concentration gradient.

Question 2

Several epidemic microbial diseases of earlier centuries incurred high death rates because they resulted in severe dehydration due to vomiting and diarrhea.Today they are usually not fatal because we have developed which of the following?

Accepted Answer

A) antiviral medications that are efficient and work well with all viruses 
B) antibiotics against the viruses in question 
C) intravenous feeding techniques 
D) medication to prevent blood loss 
E) hydrating drinks that include high concentrations of salts and glucose 
A) antiviral medications that are efficient and work well with all viruses 
B) antibiotics against the viruses in question 
C) intravenous feeding techniques 
D) medication to prevent blood loss 
E) hydrating drinks that include high concentrations of salts and glucose

Question 3

What is the force driving simple diffusion and energy source for active transport,respectively?

Accepted Answer

A) the concentration gradient; ADP 
B) the concentration gradient; ATP 
C) transmembrane pumps; electron transport 
D) phosphorylated protein carriers; ATP 
E) proton gradient; ADP 
A) the concentration gradient; ADP 
B) the concentration gradient; ATP 
C) transmembrane pumps; electron transport 
D) phosphorylated protein carriers; ATP 
E) proton gradient; ADP

Question 4

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 5

A bacterium engulfed by a white blood cell through phagocytosis will be digested by enzymes contained in

Accepted Answer

A) peroxisomes. 
B) lysosomes. 
C) Golgi vesicles. 
D) vacuoles. 
E) secretory vesicles. 
A) peroxisomes. 
B) lysosomes. 
C) Golgi vesicles. 
D) vacuoles. 
E) secretory vesicles.

Question 6

In a Paramecium,cell surface integral membrane proteins are synthesized

Accepted Answer

A) in the cytoplasm by free ribosomes. 
B) by ribosomes in the nucleus. 
C) by ribosomes bound to the rough endoplasmic reticulum. 
D) by ribosomes in the Golgi vesicles. 
E) by ribosomes bound to the inner surface of the plasma membrane. 
A) in the cytoplasm by free ribosomes. 
B) by ribosomes in the nucleus. 
C) by ribosomes bound to the rough endoplasmic reticulum. 
D) by ribosomes in the Golgi vesicles. 
E) by ribosomes bound to the inner surface of the plasma membrane.

Question 7

When biological membranes are frozen and then fractured,they tend to break along the middle of the bilayer.The best explanation for this is that

Accepted Answer

A) the integral membrane proteins are not strong enough to hold the bilayer together. 
B) water that is present in the middle of the bilayer freezes and is easily fractured. 
C) hydrophilic interactions between the opposite membrane surfaces are destroyed on freezing. 
D) the carbon-carbon bonds of the phospholipid tails are easily broken. 
E) the hydrophobic interactions that hold the membrane together are weakest at this point. 
A) the integral membrane proteins are not strong enough to hold the bilayer together. 
B) water that is present in the middle of the bilayer freezes and is easily fractured. 
C) hydrophilic interactions between the opposite membrane surfaces are destroyed on freezing. 
D) the carbon-carbon bonds of the phospholipid tails are easily broken. 
E) the hydrophobic interactions that hold the membrane together are weakest at this point.

Question 8

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) Lipids and proteins repulse each other 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) Lipids and proteins repulse each other 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.

Exam 7: Membrane Structure and Function

When a cell is in equilibrium with its environment,which of the following occurs for substances that can diffuse through the cell?

Several epidemic microbial diseases of earlier centuries incurred high death rates because they resulted in severe dehydration due to vomiting and diarrhea.Today they are usually not fatal because we have developed which of the following?

What is the force driving simple diffusion and energy source for active transport,respectively?

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

A bacterium engulfed by a white blood cell through phagocytosis will be digested by enzymes contained in

In a Paramecium,cell surface integral membrane proteins are synthesized

When biological membranes are frozen and then fractured,they tend to break along the middle of the bilayer.The best explanation for this is that

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

Introduction: Evolution and Themes of Biology

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

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

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 Signalling

Nervous Systems

Sensory and Motor Mechanisms

Animal Behaviour

An Introduction to Ecology and the Biosphere

Population Ecology

Community Ecology

Ecosystems and Restoration Ecology

Conservation Biology and Global Change

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