Question 1

Van der Waals interactions may result when ________.

Accepted Answer

A)  hybrid orbitals overlap 
B)  electrons are not symmetrically distributed in a molecule 
C)  molecules held by ionic bonds react with water 
D)  two polar covalent bonds react 
E)  a hydrogen atom loses an electron 
A)  hybrid orbitals overlap 
B)  electrons are not symmetrically distributed in a molecule 
C)  molecules held by ionic bonds react with water 
D)  two polar covalent bonds react 
E)  a hydrogen atom loses an electron B

Question 2

A series of hydrophobic side chains will congregate together as a protein folds in an aqueous solution and be stabilized by ________.

Accepted Answer

A)  disulfide bonds 
B)  van der Waals interactions 
C)  hydrogen bonds 
D)  quaternary structure bonds 
A)  disulfide bonds 
B)  van der Waals interactions 
C)  hydrogen bonds 
D)  quaternary structure bonds B

Question 3

At which level of protein structure are interactions between the side chains (R-groups) most important?

Accepted Answer

A)  primary 
B)  secondary 
C)  tertiary 
D)  quaternary 
E)  primary, secondary, tertiary, and quaternary 
A)  primary 
B)  secondary 
C)  tertiary 
D)  quaternary 
E)  primary, secondary, tertiary, and quaternary C

Question 4

What are prions?

Accepted Answer

A)  mobile segments of DNA 
B)  tiny circular molecules of RNA that can infect plants 
C)  viral DNA that attaches itself to the host genome and causes disease 
D)  misfolded versions of normal protein that can cause disease 
E)  viruses that invade bacteria 
A)  mobile segments of DNA 
B)  tiny circular molecules of RNA that can infect plants 
C)  viral DNA that attaches itself to the host genome and causes disease 
D)  misfolded versions of normal protein that can cause disease 
E)  viruses that invade bacteria

Question 5

The following question(s) are based on the 15 molecules illustrated in the accompanying figure. Each molecule may be used once, more than once, or not at all.  
-Which of the following molecules is an amino acid with a hydrophobic R-group or side chain?

Accepted Answer

A)  3 
B)  7 
C)  10 
D)  12 
E)  13 
A)  3 
B)  7 
C)  10 
D)  12 
E)  13

Question 6

Aquaporins are proteins that control the passage of water molecules across a cell membrane. The protein forms a pore, or opening, in the membrane. You isolate what you think are two different molecules of aquaporin and determine that one of the proteins has a larger pore diameter than the second. Which of the following do you conclude?

Accepted Answer

A)  These two forms of aquaporin will have identical sequences of amino acids. 
B)  These two forms of aquaporin will have different sequences of amino acids. 
C)  You will have to sequence the proteins to compare their primary structure, because it should have no effect on pore diameter. 
D)  These two forms of aquaporin have identical primary structure but differ in their tertiary structure. 
A)  These two forms of aquaporin will have identical sequences of amino acids. 
B)  These two forms of aquaporin will have different sequences of amino acids. 
C)  You will have to sequence the proteins to compare their primary structure, because it should have no effect on pore diameter. 
D)  These two forms of aquaporin have identical primary structure but differ in their tertiary structure.

Question 7

You are studying a protein that is shaped like a doughnut. The shape is a function of which level(s) of protein structure?

Accepted Answer

A)  primary only 
B)  secondary only 
C)  tertiary only 
D)  secondary and tertiary only 
E)  primary, secondary, and tertiary 
A)  primary only 
B)  secondary only 
C)  tertiary only 
D)  secondary and tertiary only 
E)  primary, secondary, and tertiary

Question 8

Upon chemical analysis, a particular polypeptide was found to contain 100 amino acids. How many peptide bonds are present in this protein?

Accepted Answer

A)  101 
B)  100 
C)  99 
D)  98 
E)  97 
A)  101 
B)  100 
C)  99 
D)  98 
E)  97

Question 9

-The structural level of a protein LEAST affected by a disruption in hydrogen bonding is the ________.

Accepted Answer

A)  primary level 
B)  secondary level 
C)  tertiary level 
D)  quaternary level 
E)  All structural levels are equally affected by a disruption in hydrogen bonding. 
A)  primary level 
B)  secondary level 
C)  tertiary level 
D)  quaternary level 
E)  All structural levels are equally affected by a disruption in hydrogen bonding.

Question 10

There are 20 different amino acids. What makes one amino acid different from another?

Accepted Answer

A)  different side chains (R-groups) attached to a carboxyl carbon 
B)  different side chains (R-groups) attached to the amino groups 
C)  different side chains (R-groups) attached to an α carbon 
D)  different structural and optical isomers 
E)  different asymmetric carbons 
A)  different side chains (R-groups) attached to a carboxyl carbon 
B)  different side chains (R-groups) attached to the amino groups 
C)  different side chains (R-groups) attached to an α carbon 
D)  different structural and optical isomers 
E)  different asymmetric carbons

Question 11

Normal hemoglobin is a tetramer, consisting of two molecules of β hemoglobin and two molecules of α hemoglobin. In sickle-cell disease, as a result of a single amino acid change, the mutant hemoglobin tetramers associate with each other and assemble into large fibers. Based on this information alone, we can conclude that sickle-cell hemoglobin exhibits ________.

Accepted Answer

A)  only altered primary structure 
B)  only altered secondary structure 
C)  only altered tertiary structure 
D)  only altered quaternary structure 
E)  altered primary structure and altered quaternary structure; the secondary and tertiary structures may or may not be altered 
A)  only altered primary structure 
B)  only altered secondary structure 
C)  only altered tertiary structure 
D)  only altered quaternary structure 
E)  altered primary structure and altered quaternary structure; the secondary and tertiary structures may or may not be altered

Question 12

The amino acids of the protein keratin are arranged predominantly in an α-helix. This secondary structure is stabilized by ________.

Accepted Answer

A)  covalent bonds 
B)  peptide bonds 
C)  ionic bonds 
D)  polar bonds 
E)  hydrogen bonds 
A)  covalent bonds 
B)  peptide bonds 
C)  ionic bonds 
D)  polar bonds 
E)  hydrogen bonds

Question 13

What type of interaction is directly responsible for the formation of secondary structure?

Accepted Answer

A)  peptide bonds between adjacent amino acids 
B)  peptide bonds between nonadjacent amino acids 
C)  hydrogen bonds between sections of the polypeptide backbone 
D)  hydrogen bonds between side chains of amino acids 
A)  peptide bonds between adjacent amino acids 
B)  peptide bonds between nonadjacent amino acids 
C)  hydrogen bonds between sections of the polypeptide backbone 
D)  hydrogen bonds between side chains of amino acids

Question 14

At about pH 7 in most cells, what happens to the amino R-group on an amino acid?

Accepted Answer

A)  It acts as a base and gains a proton, giving it a positive charge. 
B)  It acts as an acid and loses a proton, giving it a negative charge. 
C)  It is reduced and tends to act as an electron donor in redox reactions. 
D)  It remains neutral, like water, and does not have a charge. 
A)  It acts as a base and gains a proton, giving it a positive charge. 
B)  It acts as an acid and loses a proton, giving it a negative charge. 
C)  It is reduced and tends to act as an electron donor in redox reactions. 
D)  It remains neutral, like water, and does not have a charge.

Question 15

What component of amino acid structure varies among different amino acids?

Accepted Answer

A)  the long carbon-hydrogen tails of the molecule 
B)  the presence of a central C atom 
C)  the components of the R-group 
D)  the glycerol molecule that forms the backbone of the amino acid 
A)  the long carbon-hydrogen tails of the molecule 
B)  the presence of a central C atom 
C)  the components of the R-group 
D)  the glycerol molecule that forms the backbone of the amino acid

Question 16

Misfolding of polypeptides is a serious problem in cells. Which of the following diseases are associated with an accumulation of misfolded polypeptides?

Accepted Answer

A)  Alzheimer's only 
B)  Parkinson's only 
C)  diabetes mellitus only 
D)  Alzheimer's and Parkinson's only 
E)  Alzheimer's, Parkinson's, and diabetes mellitus 
A)  Alzheimer's only 
B)  Parkinson's only 
C)  diabetes mellitus only 
D)  Alzheimer's and Parkinson's only 
E)  Alzheimer's, Parkinson's, and diabetes mellitus

Question 17

The following question(s) are based on the 15 molecules illustrated in the accompanying figure. Each molecule may be used once, more than once, or not at all.  
-Which bonds are created during the formation of the primary structure of a protein?

Accepted Answer

A)  peptide bonds 
B)  hydrogen bonds 
C)  disulfide bonds 
D)  phosphodiester bonds 
E)  peptide bonds, hydrogen bonds, and disulfide bonds 
A)  peptide bonds 
B)  hydrogen bonds 
C)  disulfide bonds 
D)  phosphodiester bonds 
E)  peptide bonds, hydrogen bonds, and disulfide bonds

Question 18

Which of the following is the strongest evidence that protein structure and function are correlated?

Accepted Answer

A)  Proteins function best at certain temperatures. 
B)  Proteins have four distinct levels of structure and many functions. 
C)  Enzymes tend to be globular in shape. 
D)  Denatured (unfolded) proteins do not function normally. 
A)  Proteins function best at certain temperatures. 
B)  Proteins have four distinct levels of structure and many functions. 
C)  Enzymes tend to be globular in shape. 
D)  Denatured (unfolded) proteins do not function normally.

Question 19

A hydrocarbon skeleton is covalently bonded to an amino group at one end and a carboxyl group at the other end. When placed in water this molecule would function ________.

Accepted Answer

A)  only as an acid because of the carboxyl group 
B)  only as a base because of the amino group 
C)  as an acid and a base 
D)  as neither an acid nor a base 
E)  It is impossible to determine how it would function, based on the information provided. 
A)  only as an acid because of the carboxyl group 
B)  only as a base because of the amino group 
C)  as an acid and a base 
D)  as neither an acid nor a base 
E)  It is impossible to determine how it would function, based on the information provided.

Question 20

Which two functional groups are always found in amino acids?

Accepted Answer

A)  ketone and methyl groups 
B)  carbonyl and amino groups 
C)  carboxyl and amino groups 
D)  amino and sulfhydryl groups 
E)  hydroxyl and carboxyl groups 
A)  ketone and methyl groups 
B)  carbonyl and amino groups 
C)  carboxyl and amino groups 
D)  amino and sulfhydryl groups 
E)  hydroxyl and carboxyl groups

Exam 3: Protein Structure and Function

Van der Waals interactions may result when ________.

A series of hydrophobic side chains will congregate together as a protein folds in an aqueous solution and be stabilized by ________.

At which level of protein structure are interactions between the side chains (R-groups) most important?

What are prions?

The following question(s) are based on the 15 molecules illustrated in the accompanying figure. Each molecule may be used once, more than once, or not at all. -Which of the following molecules is an amino acid with a hydrophobic R-group or side chain?

You are studying a protein that is shaped like a doughnut. The shape is a function of which level(s) of protein structure?

Upon chemical analysis, a particular polypeptide was found to contain 100 amino acids. How many peptide bonds are present in this protein?

-The structural level of a protein LEAST affected by a disruption in hydrogen bonding is the ________.

There are 20 different amino acids. What makes one amino acid different from another?

The amino acids of the protein keratin are arranged predominantly in an α-helix. This secondary structure is stabilized by ________.

What type of interaction is directly responsible for the formation of secondary structure?

At about pH 7 in most cells, what happens to the amino R-group on an amino acid?

What component of amino acid structure varies among different amino acids?

Misfolding of polypeptides is a serious problem in cells. Which of the following diseases are associated with an accumulation of misfolded polypeptides?

The following question(s) are based on the 15 molecules illustrated in the accompanying figure. Each molecule may be used once, more than once, or not at all. -Which bonds are created during the formation of the primary structure of a protein?

Which of the following is the strongest evidence that protein structure and function are correlated?

A hydrocarbon skeleton is covalently bonded to an amino group at one end and a carboxyl group at the other end. When placed in water this molecule would function ________.

Which two functional groups are always found in amino acids?

Biology and the Tree of Life

Water and Carbon: the Chemical Basis of Life

Nucleic Acids and the Rna World

An Introduction to Carbohydrates

Ecosystems and Global Ecology

Lipids, Membranes, and the First Cells

Inside the Cell

Energy and Enzymes: an Introduction to Metabolism

Cellular Respiration and Fermentation

Photosynthesis

Cellcell Interactions

The Cell Cycle

Meiosis

Mendel and the Gene

Dna and the Gene: Synthesis and Repair

How Genes Work

Transcription, Rna Processing, and Translation

Control of Gene Expression in Bacteria

Control of Gene Expression in Eukaryotes

The Molecular Revolution: Biotechnology and Beyond

Genes, Development, and Evolution

Evolution by Natural Selection

Evolutionary Processes

Speciation

Phylogenies and the History of Life

Bacteria and Archaea

Protists

Green Algae and Land Plants

Fungi

An Introduction to Animals

Protostome Animals

Deuterostome Animals

Viruses

Plant Form and Function

Water and Sugar Transport in Plants

Plant Nutrition

Plant Sensory Systems, Signals, and Responses

Plant Reproduction and Development

Animal Form and Function

Water and Electrolyte Balance in Animals

Animal Nutrition

Gas Exchange and Circulation

Animal Nervous Systems

Animal Sensory Systems

Animal Movement

Chemical Signals in Animals

Animal Reproduction and Development

The Immune System in Animals

An Introduction to Ecology

Behavioral Ecology

Population Ecology

Community Ecology

Biodiversity and Conservation Biology

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