Question 1

Monomers are joined together by _______ and broken down by _______.

Accepted Answer

A)  proteins; lipids 
B)  condensation; hydrolysis 
C)  phosphorylation; dephosphorylation 
D)  acids; bases 
E)  hydrogen; oxygen 
A)  proteins; lipids 
B)  condensation; hydrolysis 
C)  phosphorylation; dephosphorylation 
D)  acids; bases 
E)  hydrogen; oxygen

Question 2

Which statement about lipids is true?

Accepted Answer

A)  They are readily soluble in water. 
B)  They function as catalysts of chemical reactions. 
C)  They absorb large amounts of energy when broken down. 
D)  They may form two layers when mixed with organic solvents. 
E)  They can act as an energy storehouse. 
A)  They are readily soluble in water. 
B)  They function as catalysts of chemical reactions. 
C)  They absorb large amounts of energy when broken down. 
D)  They may form two layers when mixed with organic solvents. 
E)  They can act as an energy storehouse.

Question 3

Refer to the figure below, showing the structure of l-alanine.   Which is the correct structure for d-alanine?

Accepted Answer

A)    
B)    
C)    
D)    
E)    
A)    
B)    
C)    
D)    
E)

Question 4

Glucose is a monosaccharide, maltose is a disaccharide composed of glucose, and glycogen is a polysaccharide composed of glucose.Compare the functions of these three carbohydrates in the human body.

Accepted Answer

Glucose is a molecule used as a fuel for

Question 5

If a protein is placed in urea, it will retain only its

Accepted Answer

A)  peptide bonds. 
B)  F1F1F1S1F1F1F10 sheets. 
C)  F1F1F1S1F1F1F10 sheets. 
D)  hydrogen bonds. 
E)  ionic interactions. 
A)  peptide bonds. 
B)  F1F1F1S1F1F1F10 sheets. 
C)  F1F1F1S1F1F1F10 sheets. 
D)  hydrogen bonds. 
E)  ionic interactions.

Question 6

A condensation reaction

Accepted Answer

A)  uses carboxyl groups in beginning catabolism. 
B)  requires oxygen when forming glycosidic linkages. 
C)  removes water when linking together amino acids. 
D)  gives off hydrogen during the formation of hydrogen bonds. 
E)  adds hydroxyl groups to nucleic acid linkages. 
A)  uses carboxyl groups in beginning catabolism. 
B)  requires oxygen when forming glycosidic linkages. 
C)  removes water when linking together amino acids. 
D)  gives off hydrogen during the formation of hydrogen bonds. 
E)  adds hydroxyl groups to nucleic acid linkages.

Question 7

Which statement about fatty acids is true?

Accepted Answer

A)  They contain three fats bonded to a glycerol. 
B)  They are composed of a hydrocarbon tail and a carboxyl group. 
C)  They are carbohydrates linked to a hydrocarbon chain. 
D)  They contain glycerol and a carboxyl group. 
E)  They become saturated at low pH. 
A)  They contain three fats bonded to a glycerol. 
B)  They are composed of a hydrocarbon tail and a carboxyl group. 
C)  They are carbohydrates linked to a hydrocarbon chain. 
D)  They contain glycerol and a carboxyl group. 
E)  They become saturated at low pH.

Question 8

The three-dimensional structure of protein

Accepted Answer

A)  is determined by the sequence of amino acids in the polypeptide chain. 
B)  always contains multiple polypeptide chains. 
C)  cannot be altered once folded by chaperone proteins. 
D)  will be different in different organisms, even when the amino acid sequence is the same. 
E)  is not related to its function. 
A)  is determined by the sequence of amino acids in the polypeptide chain. 
B)  always contains multiple polypeptide chains. 
C)  cannot be altered once folded by chaperone proteins. 
D)  will be different in different organisms, even when the amino acid sequence is the same. 
E)  is not related to its function.

Question 9

Molecules containing a large number of hydroxyl groups are

Accepted Answer

A)  basic. 
B)  structurally less stable than those with fewer hydroxyls. 
C)  complex macromolecules. 
D)  nonpolar. 
E)  soluble in water. 
A)  basic. 
B)  structurally less stable than those with fewer hydroxyls. 
C)  complex macromolecules. 
D)  nonpolar. 
E)  soluble in water.

Question 10

Refer to the table below summarizing data obtained from chemical analysis of two proteins isolated from different tissues of a mouse-skin and bone.   Can it be concluded from this data that the two proteins are the same?

Accepted Answer

A)  Yes, because they have the same size and the same total number of amino acids. 
B)  Yes, because every amino acid tested is present in the same number in both proteins. 
C)  No, because no two proteins from different tissues in the same organism will be the same. 
D)  No, because the data do not reveal any information about the sequences of the amino acids in the proteins. 
E)  No, because the data do not reveal whether the other amino acids are present or in equal numbers in the proteins. 
A)  Yes, because they have the same size and the same total number of amino acids. 
B)  Yes, because every amino acid tested is present in the same number in both proteins. 
C)  No, because no two proteins from different tissues in the same organism will be the same. 
D)  No, because the data do not reveal any information about the sequences of the amino acids in the proteins. 
E)  No, because the data do not reveal whether the other amino acids are present or in equal numbers in the proteins.

Question 11

Starch and glycogen, which are both polysaccharides, differ structurally in that glycogen _______, whereas starch _______.

Accepted Answer

A)  is highly branched; is moderately branched 
B)  consists of parallel strands; is highly branched 
C)  consists of a combination of branching and parallel strands; is moderately branched 
D)  is moderately branched; consists of parallel strands 
E)  is highly branched; consists of parallel strands 
A)  is highly branched; is moderately branched 
B)  consists of parallel strands; is highly branched 
C)  consists of a combination of branching and parallel strands; is moderately branched 
D)  is moderately branched; consists of parallel strands 
E)  is highly branched; consists of parallel strands

Question 12

What type of amino acid side chains would you expect to find on the surface of a protein embedded in a cell membrane?

Accepted Answer

A)  Short 
B)  Hydrophobic 
C)  Hydrophilic 
D)  Charged 
E)  Polar, but not charged 
A)  Short 
B)  Hydrophobic 
C)  Hydrophilic 
D)  Charged 
E)  Polar, but not charged

Question 13

A research group discovers that a reagent can be used to form covalent cross-links between various types of atoms in both small molecules and proteins.They add the reagent to a mixture of 14C-lactose and a protein that is thought to have a specific binding site for lactose.What should they do next to draw a conclusion about whether the protein specifically binds lactose?

Accepted Answer

A)  Determine whether any radiolabel becomes covalently linked to protein, and repeat the experiment under high concentrations of urea to see if the sites of radiolabel linkage to the protein change. 
B)  Denature the protein and observe whether radiolabel is released, and then repeat the experiment with unlabeled lactose. 
C)  Measure the stoichiometry of 14C-labeled lactose covalently bound to protein to see if a 1:1 ratio is observed, and then use chemical analysis to identify the specific amino acids involved in the covalent bonds. 
D)  Determine how much radiolabel becomes covalently linked to the protein, and then repeat the experiment using protein with random amino acid substitutions throughout its polypeptide chain. 
E)  Identify amino acid residues that are covalently linked to 14C-lactose, and then repeat the experiment using a mutant version of the protein in which all of these residues are omitted from the polypeptide chain. 
A)  Determine whether any radiolabel becomes covalently linked to protein, and repeat the experiment under high concentrations of urea to see if the sites of radiolabel linkage to the protein change. 
B)  Denature the protein and observe whether radiolabel is released, and then repeat the experiment with unlabeled lactose. 
C)  Measure the stoichiometry of 14C-labeled lactose covalently bound to protein to see if a 1:1 ratio is observed, and then use chemical analysis to identify the specific amino acids involved in the covalent bonds. 
D)  Determine how much radiolabel becomes covalently linked to the protein, and then repeat the experiment using protein with random amino acid substitutions throughout its polypeptide chain. 
E)  Identify amino acid residues that are covalently linked to 14C-lactose, and then repeat the experiment using a mutant version of the protein in which all of these residues are omitted from the polypeptide chain.

Question 14

Cellulose is

Accepted Answer

A)  a structural organic compound. 
B)  made up of α-glycosidic linkages. 
C)  readily soluble in water. 
D)  a form of energy storage. 
E)  highly unstable. 
A)  a structural organic compound. 
B)  made up of α-glycosidic linkages. 
C)  readily soluble in water. 
D)  a form of energy storage. 
E)  highly unstable.

Question 15

When a cysteine residue in a protein is replaced with serine, the protein folds normally and exhibits 95 percent of its normal biological activity.However, when this same cysteine residue is replaced with glycine, the protein does not fold normally and exhibits only 35 percent of its normal biological activity.Which hypothesis is both reasonable and consistent with these observations?

Accepted Answer

A)  A hydrogen bond between the cysteine side chain and another residue in the interior of the protein helps stabilize the protein's tertiary structure. 
B)  The cysteine side chain is exposed to the external environment, where it forms salt bridges with ions dissolved in the water surrounding the protein. 
C)  The cysteine residue forms a disulfide bridge with another cysteine in the polypeptide chain to stabilize the protein's tertiary structure. 
D)  A salt bridge between the cysteine side chain and an acidic residue in the interior of the protein helps stabilize the protein's tertiary structure. 
E)  The cysteine side chain is located in a tight bend in the polypeptide chain, where only a small side chain can be accommodated. 
A)  A hydrogen bond between the cysteine side chain and another residue in the interior of the protein helps stabilize the protein's tertiary structure. 
B)  The cysteine side chain is exposed to the external environment, where it forms salt bridges with ions dissolved in the water surrounding the protein. 
C)  The cysteine residue forms a disulfide bridge with another cysteine in the polypeptide chain to stabilize the protein's tertiary structure. 
D)  A salt bridge between the cysteine side chain and an acidic residue in the interior of the protein helps stabilize the protein's tertiary structure. 
E)  The cysteine side chain is located in a tight bend in the polypeptide chain, where only a small side chain can be accommodated.

Question 16

Refer to the figure below showing the structure of sucrose.   How would sucrose be expected to differ from the monosaccharide glucose?

Accepted Answer

A)  Sucrose would not be able to form hydrogen bonds, whereas glucose would participate in hydrogen bonding. 
B)  In sucrose the alpha and beta ring forms would not interconvert at carbon 1 of the glucose unit, whereas they would interconvert at carbon 1 in glucose. 
C)  Sucrose would not provide a source of energy for a cell, whereas glucose would provide a source of energy. 
D)  Sucrose would not be soluble in water, whereas glucose would be soluble in water. 
E)  The carbon atoms in sucrose would not be used as building blocks for other molecules in the cell, whereas the carbon atoms in glucose would serve as cellular building blocks. 
A)  Sucrose would not be able to form hydrogen bonds, whereas glucose would participate in hydrogen bonding. 
B)  In sucrose the alpha and beta ring forms would not interconvert at carbon 1 of the glucose unit, whereas they would interconvert at carbon 1 in glucose. 
C)  Sucrose would not provide a source of energy for a cell, whereas glucose would provide a source of energy. 
D)  Sucrose would not be soluble in water, whereas glucose would be soluble in water. 
E)  The carbon atoms in sucrose would not be used as building blocks for other molecules in the cell, whereas the carbon atoms in glucose would serve as cellular building blocks.

Question 17

Two biologically important polymers of glucose contain the same number of monomers and have the same mass, yet one is soluble in water and the other is not.This can be explained by the fact that the two polymers

Accepted Answer

A)  differ in their proportions of glucose units existing in ring form versus straight-chain form. 
B)  differ in the amount of hydrogen bonding taking place between glucose residues in their chains. 
C)  were biosynthesized in different cells by different enzymes. 
D)  contain glycosidic linkages between different oxygen and carbon atoms in the monomeric units. 
E)  have different biological functions. 
A)  differ in their proportions of glucose units existing in ring form versus straight-chain form. 
B)  differ in the amount of hydrogen bonding taking place between glucose residues in their chains. 
C)  were biosynthesized in different cells by different enzymes. 
D)  contain glycosidic linkages between different oxygen and carbon atoms in the monomeric units. 
E)  have different biological functions.

Question 18

Chondroitin sulfate is a complex polysaccharide found in human cartilage.It consists of glycosaminoglycans, glucuronic acid, and glucosamine, three molecules that all have glucose molecules as their structural basis.Chondroitin sulfate contributes to the weight-bearing and shock-absorbing properties of cartilage.It also inhibits enzymes that tend to break down cartilage.Thus, chondroitin sulfate is a good example of how chemical modification of _______ in a biopolymer leads to unique characteristics of the polymer that can address a variety of functions in an organism.

Accepted Answer

The answer of Chondroitin sulfate is a complex polysaccharide found...

Question 19

Protein structure can be affected by environmental conditions, which eventually can lead to denaturation.Differentiate between four environmental effects that can denature proteins, and explain how they affect protein structure.

Accepted Answer

Increased temperature can break hydrogen

Question 20

Each amino acid has a unique _______ group.

Accepted Answer

A)  amino 
B)  hydroxyl 
C)  carboxyl 
D)  R 
E)  phosphate 
A)  amino 
B)  hydroxyl 
C)  carboxyl 
D)  R 
E)  phosphate

Exam 3: Proteins, Carbohydrates, and Lipids

Monomers are joined together by _______ and broken down by _______.

Which statement about lipids is true?

Refer to the figure below, showing the structure of l-alanine. Which is the correct structure for d-alanine?

Glucose is a monosaccharide, maltose is a disaccharide composed of glucose, and glycogen is a polysaccharide composed of glucose.Compare the functions of these three carbohydrates in the human body.

If a protein is placed in urea, it will retain only its

A condensation reaction

Which statement about fatty acids is true?

The three-dimensional structure of protein

Molecules containing a large number of hydroxyl groups are

Refer to the table below summarizing data obtained from chemical analysis of two proteins isolated from different tissues of a mouse-skin and bone. Can it be concluded from this data that the two proteins are the same?

Starch and glycogen, which are both polysaccharides, differ structurally in that glycogen _______, whereas starch _______.

What type of amino acid side chains would you expect to find on the surface of a protein embedded in a cell membrane?

Cellulose is

Refer to the figure below showing the structure of sucrose. How would sucrose be expected to differ from the monosaccharide glucose?

Two biologically important polymers of glucose contain the same number of monomers and have the same mass, yet one is soluble in water and the other is not.This can be explained by the fact that the two polymers

Protein structure can be affected by environmental conditions, which eventually can lead to denaturation.Differentiate between four environmental effects that can denature proteins, and explain how they affect protein structure.

Each amino acid has a unique _______ group.

Studying Life

Small Molecules and the Chemistry of Life

Nucleic Acids and the Origin of Life

Cells: the Working Units of Life

Cell Membranes

Cell Communication and Multicellularity

Energy, Enzymes, and Metabolism

Pathways That Harvest Chemical Energy

Photosynthesis: Energy From Sunlight

The Cell Cycle and Cell Division

Inheritance, Genes, and Chromosomes

Dna and Its Role in Heredity

From Dna to Protein: Gene Expression

Gene Mutation and Molecular Medicine

Regulation of Gene Expression

Genomes

Recombinant Dna and Biotechnology

Mechanisms of Evolution

Reconstructing and Using Phylogenies

Speciation

Evolution of Genes and Genomes

The History of Life on Earth

Bacteria, Archaea, and Viruses

The Origin and Diversification of Eukaryotes

Plants Without Seeds: From Water to Land

The Evolution of Seed Plants

The Evolution and Diversity of Fungi

Animal Origins and the Evolution of Body Plans

Protostome Animals

Deuterostome Animals

The Plant Body

Transport in Plants

Plant Nutrition

Regulation of Plant Growth

Reproduction in Flowering Plants

Plant Responses to Environmental Challenges

Physiology, Homeostasis, and Temperature Regulation

Animal Hormones

Immunology: Animal Defense Systems

Animal Reproduction

Animal Development

Neurons, Glia, and Nervous Systems

Sensory Systems

The Mammalian Nervous System: Structure and Higher Functions

Musculoskeletal Systems

Gas Exchange

Circulatory Systems

Nutrition, Digestion, and Absorption

Salt and Water Balance and Nitrogen Excretion

Animal Behavior

The Physical Environment and Biogeography of Life

Populations

Species Interactions

Communities

Ecosystems

A Changing Biosphere

Filters

Monomers are joined together by _ and broken down by _.

Starch and glycogen, which are both polysaccharides, differ structurally in that glycogen _, whereas starch _.