Meisenberg: Principles of Medical Biochemistry, 3rd Edition
Chapter 1: Introduction to Biomolecules
Test Bank
MULTIPLE CHOICE
1. β Linkages are important in structural polysaccharides because:
a. They are easily hydrolyzed by glycosidase enzymes.
b. They allow the chains to form compact coils.
c. They cause the chains to exist in an extended form, thus allowing them to form
fibers.
d. They cause the chains to absorb more water.
e. They can be formed by any hydroxy group in the monomer, whereas linkages
can be formed only by C-1.
ANS: C
Cellulose, chitin, and peptidoglycan are examples of fibrous polysaccharides that are
formed from β-linked units.
2. What is the difference between α-D-glucose and α-D-galactose?
a. They are mirror images of each other.
b. They differ in the configuration of substituents at C-4.
c. One is an aldose and the other is a ketose.
d. They are anomers.
e. One forms only O-glycosidic bonds, and the other forms only N-glycosidic bonds.
ANS: B
Galactose is a C-4 epimer of glucose (and vice versa). Epimers are not mirror images of
one another because other asymmetrical carbons are also present in the molecule.
3. What is the major difference between glycogen and amylose?
a. Glycogen contains only glucose, and amylose contains some fructose in addition to
glucose.
b. Glycogen is a storage polysaccharide, and amylose is a structural polysaccharide
of the extracellular matrix.
c. Glycogen is branched, and amylose is not.
d. Glycogen contains some β linkages, but amylose contains only α linkages.
e. Glycogen is stored in the liver, and amylose is stored in skeletal muscle.
ANS: C
Glycogen is a branched polysaccharide similar to amylopectin, a form of starch that is
found together with unbranched amylose in the starch granules of plants.
Copyright © 2012, 2006, 1998 by Saunders, an imprint of Elsevier, Inc.
,4. Unlike covalent bonds, all noncovalent interactions are:
a. Formed in irreversible reactions.
b. Constantly forming and breaking on the molecular time scale.
c. Susceptible to cleavage by strong acids and bases.
d. Classified as energy-rich, because they are cleaved easily.
e. Independent of the solvent that surrounds the bond-forming groups.
ANS: B
Because noncovalent bonds form and break constantly, all noncovalent interactions are
reversible.
Copyright © 2012, 2006, 1998 by Saunders, an imprint of Elsevier, Inc.
,Meisenberg: Principles of Medical Biochemistry, 3rd Edition
Chapter 2: Introduction to Protein Structure
Test Bank
MULTIPLE CHOICE
1. Which of the following is true about the tertiary structure of proteins?
a. Disulfide bonds are part of the tertiary structure.
b. Only proteins with more than one polypeptide subunit have a tertiary structure.
c. Proteins with tertiary structure do not contain α helix or β-pleated sheet.
d. Van der Waals interactions play no role in the tertiary structure.
e. Interactions between hydrophobic amino acid side chains are important for hold
the tertiary structure together.
ANS: E
Hydrophobic groups associate with one another to minimize the thermodynamically
unfavorable interface between lipid and water. Hydrophobic interactions and van der
Waals interactions prevail in the core of globular proteins.
2. Amino acids at the isoelectric point in the titration curve have a net charge of:
a. 1.
b. +1.
c. +2.
d. 0.
e. –2.
ANS: D
This is the definition of the isoelectric point.
3. Which amino acid residues are used as attachment sites for covalently bound
oligosaccharides in glycoproteins?
a. Asparagine and serine.
b. Tryptophan and glutamic acid.
c. Alanine and lysine.
d. Arginine and proline.
e. Leucine and histidine.
ANS: A
N-linked carbohydrate is bound to asparagine, and O-linked carbohydrate is bound to
serine or threonine (or, in collagen, to hydroxylysine).
Copyright © 2012, 2006, 1998 by Saunders, an imprint of Elsevier, Inc.
, 4. Which of the following is true regarding the structure shown?
-CH2-CH2-COO–
a. Side chain of glutamine; normally found in the interior of globular proteins.
b. Side chain of glutamine; normally found on the surface of globular proteins.
c. Side chain of glutamate; normally found in the interior of globular proteins.
d. Side chain of glutamate; normally found on the surface of globular proteins.
e. Side chain of the “nonstandard” amino acid -carboxyglutamate, found only in
some clotting factors.
ANS: D
Unlike glutamine, glutamate is negatively charged. All negatively charged amino acid
side chains prefer the surface of globular proteins, where they can interact with water and
dissolved ions.
5. In the tripeptide glutathione (γ-glutamyl-cysteinyl-glycine), the side chain carboxyl
group of glutamate forms a peptide bond with the α-amino group of cysteine. The α-
amino and α-carboxyl groups of glutamate do not participate in peptide bonds.
Approximately what is the isoelectric point (pK) of glutathione?
a. 1.5.
b. 10.0.
c. 3.0.
d. 6.5.
e. 9.0.
ANS: C
There is an α-amino group (of glutamate) with a pK near 9 or 10, an α-carboxyl group (of
glutamate) with a pK near 2, a carboxyl terminus (formed by glycine) with a pK near 4,
and a cysteine sulfhydryl group (SH) with a pK near 8. The isoelectric point is halfway
between the pK values of the two carboxyl groups.
6. Noncovalent bonds essential for the formation of the α helix and -pleated sheet are:
a. Disulfide bonds.
b. Van der Waals interactions.
c. Salt bridges.
d. Hydrogen bonds.
e. Hydrophobic forces.
ANS: D
The hydrogen bonds are formed between the components of the peptide bonds.
7. Histones are proteins that bind to negatively charged phosphate groups of DNA. An
amino acid in the histones that can mediate this binding is:
a. Valine.
Copyright © 2012, 2006, 1998 by Saunders, an imprint of Elsevier, Inc.
Chapter 1: Introduction to Biomolecules
Test Bank
MULTIPLE CHOICE
1. β Linkages are important in structural polysaccharides because:
a. They are easily hydrolyzed by glycosidase enzymes.
b. They allow the chains to form compact coils.
c. They cause the chains to exist in an extended form, thus allowing them to form
fibers.
d. They cause the chains to absorb more water.
e. They can be formed by any hydroxy group in the monomer, whereas linkages
can be formed only by C-1.
ANS: C
Cellulose, chitin, and peptidoglycan are examples of fibrous polysaccharides that are
formed from β-linked units.
2. What is the difference between α-D-glucose and α-D-galactose?
a. They are mirror images of each other.
b. They differ in the configuration of substituents at C-4.
c. One is an aldose and the other is a ketose.
d. They are anomers.
e. One forms only O-glycosidic bonds, and the other forms only N-glycosidic bonds.
ANS: B
Galactose is a C-4 epimer of glucose (and vice versa). Epimers are not mirror images of
one another because other asymmetrical carbons are also present in the molecule.
3. What is the major difference between glycogen and amylose?
a. Glycogen contains only glucose, and amylose contains some fructose in addition to
glucose.
b. Glycogen is a storage polysaccharide, and amylose is a structural polysaccharide
of the extracellular matrix.
c. Glycogen is branched, and amylose is not.
d. Glycogen contains some β linkages, but amylose contains only α linkages.
e. Glycogen is stored in the liver, and amylose is stored in skeletal muscle.
ANS: C
Glycogen is a branched polysaccharide similar to amylopectin, a form of starch that is
found together with unbranched amylose in the starch granules of plants.
Copyright © 2012, 2006, 1998 by Saunders, an imprint of Elsevier, Inc.
,4. Unlike covalent bonds, all noncovalent interactions are:
a. Formed in irreversible reactions.
b. Constantly forming and breaking on the molecular time scale.
c. Susceptible to cleavage by strong acids and bases.
d. Classified as energy-rich, because they are cleaved easily.
e. Independent of the solvent that surrounds the bond-forming groups.
ANS: B
Because noncovalent bonds form and break constantly, all noncovalent interactions are
reversible.
Copyright © 2012, 2006, 1998 by Saunders, an imprint of Elsevier, Inc.
,Meisenberg: Principles of Medical Biochemistry, 3rd Edition
Chapter 2: Introduction to Protein Structure
Test Bank
MULTIPLE CHOICE
1. Which of the following is true about the tertiary structure of proteins?
a. Disulfide bonds are part of the tertiary structure.
b. Only proteins with more than one polypeptide subunit have a tertiary structure.
c. Proteins with tertiary structure do not contain α helix or β-pleated sheet.
d. Van der Waals interactions play no role in the tertiary structure.
e. Interactions between hydrophobic amino acid side chains are important for hold
the tertiary structure together.
ANS: E
Hydrophobic groups associate with one another to minimize the thermodynamically
unfavorable interface between lipid and water. Hydrophobic interactions and van der
Waals interactions prevail in the core of globular proteins.
2. Amino acids at the isoelectric point in the titration curve have a net charge of:
a. 1.
b. +1.
c. +2.
d. 0.
e. –2.
ANS: D
This is the definition of the isoelectric point.
3. Which amino acid residues are used as attachment sites for covalently bound
oligosaccharides in glycoproteins?
a. Asparagine and serine.
b. Tryptophan and glutamic acid.
c. Alanine and lysine.
d. Arginine and proline.
e. Leucine and histidine.
ANS: A
N-linked carbohydrate is bound to asparagine, and O-linked carbohydrate is bound to
serine or threonine (or, in collagen, to hydroxylysine).
Copyright © 2012, 2006, 1998 by Saunders, an imprint of Elsevier, Inc.
, 4. Which of the following is true regarding the structure shown?
-CH2-CH2-COO–
a. Side chain of glutamine; normally found in the interior of globular proteins.
b. Side chain of glutamine; normally found on the surface of globular proteins.
c. Side chain of glutamate; normally found in the interior of globular proteins.
d. Side chain of glutamate; normally found on the surface of globular proteins.
e. Side chain of the “nonstandard” amino acid -carboxyglutamate, found only in
some clotting factors.
ANS: D
Unlike glutamine, glutamate is negatively charged. All negatively charged amino acid
side chains prefer the surface of globular proteins, where they can interact with water and
dissolved ions.
5. In the tripeptide glutathione (γ-glutamyl-cysteinyl-glycine), the side chain carboxyl
group of glutamate forms a peptide bond with the α-amino group of cysteine. The α-
amino and α-carboxyl groups of glutamate do not participate in peptide bonds.
Approximately what is the isoelectric point (pK) of glutathione?
a. 1.5.
b. 10.0.
c. 3.0.
d. 6.5.
e. 9.0.
ANS: C
There is an α-amino group (of glutamate) with a pK near 9 or 10, an α-carboxyl group (of
glutamate) with a pK near 2, a carboxyl terminus (formed by glycine) with a pK near 4,
and a cysteine sulfhydryl group (SH) with a pK near 8. The isoelectric point is halfway
between the pK values of the two carboxyl groups.
6. Noncovalent bonds essential for the formation of the α helix and -pleated sheet are:
a. Disulfide bonds.
b. Van der Waals interactions.
c. Salt bridges.
d. Hydrogen bonds.
e. Hydrophobic forces.
ANS: D
The hydrogen bonds are formed between the components of the peptide bonds.
7. Histones are proteins that bind to negatively charged phosphate groups of DNA. An
amino acid in the histones that can mediate this binding is:
a. Valine.
Copyright © 2012, 2006, 1998 by Saunders, an imprint of Elsevier, Inc.
