,
,
,
,
,Chapter 1 The Foundations of Biochemistry 3
10. Chemical foundations
Page: 14 Difficulty: 1 Ans: B
What functional groups are present on this molecule?
A) ether and aldehyde
B) hydroxyl and aldehyde
C) hydroxyl and carboxylic acid
D) hydroxyl and ester
E) hydroxyl and ketone
11. Chemical foundations
Page: 16 Difficulty: 1 Ans: D
The macromolecules that serve in the storage and transmission of genetic information are:
A) carbohydrates.
B) lipids.
C) membranes.
D) nucleic acids.
E) proteins.
12. Chemical foundations
Page: 17 Difficulty: 1 Ans: D
Stereoisomers that are nonsuperimposable mirror images of each other are known as:
A) anomers.
B) cis-trans isomers.
C) diastereoisomers.
D) enantiomers.
E) geometric isomers.
13. Chemical foundations
Page: 20 Difficulty: 3 Ans: E
The enzyme fumarase catalyzes the reversible hydration of fumaric acid to l-malate, but it will not
catalyze the hydration of maleic acid, the cis isomer of fumaric acid. This is an example of:
A) biological activity.
B) chiral activity.
C) racemization.
D) stereoisomerization.
E) stereospecificity.
,4 Chapter 1 The Foundations of Biochemistry
14. Physical foundations
Pages: 21-22 Difficulty: 2 Ans: A
Humans maintain a nearly constant level of hemoglobin by continually synthesizing and degrading it.
This is an example of a(n):
A) dynamic steady state.
B) equilibrium state.
C) exergonic change.
D) free-energy change.
E) waste of energy.
15. Physical foundations
Page: 23 Difficulty: 1 Ans: C
If heat energy is absorbed by the system during a chemical reaction, the reaction is said to be:
A) at equilibrium.
B) endergonic.
C) endothermic.
D) exergonic.
E) exothermic.
16. Physical foundations
Page: 23 Difficulty: 2 Ans: D
If the free energy change G for a reaction is -46.11 kJ/mol, the reaction is:
A) at equilibrium.
B) endergonic.
C) endothermic.
D) exergonic.
E) exothermic.
17. Physical foundations
Page: 23 Difficulty: 2 Ans: C
The major carrier of chemical energy in all cells is:
A) acetyl triphosphate.
B) adenosine monophosphate.
C) adenosine triphosphate.
D) cytosine tetraphosphate.
E) uridine diphosphate.
18. Physical foundations
Page: 26 Difficulty: 2 Ans: A
Enzymes are biological catalysts that enhance the rate of a reaction by:
A) decreasing the activation energy.
B) decreasing the amount of free energy released.
C) increasing the activation energy.
D) increasing the amount of free energy released.
E) increasing the energy of the transition state.
,Chapter 1 The Foundations of Biochemistry 5
19. Physical foundations
Page: 27 Difficulty: 1 Ans: B
Energy requiring metabolic pathways that yield complex molecules from simpler precursors are:
A) amphibolic.
B) anabolic.
C) autotrophic.
D) catabolic.
E) heterotrophic.
20. Genetic foundations
Page: 29 Difficulty: 1 Ans: A
Hereditary information (with the exception of some viruses) is preserved in:
A) deoxyribonucleic acid.
B) membrane structures.
C) nuclei.
D) polysaccharides.
E) ribonucleic acid.
21. Genetic foundations
Page: 29 Difficulty: 2 Ans: C
When a region of DNA must be repaired by removing and replacing some of the nucleotides, what
ensures that the new nucleotides are in the correct sequence?
A) DNA cannot be repaired and this explains why mutations occur.
B) Specific enzymes bind the correct nucleotides.
C) The new nucleotides basepair accurately with those on the complementary strand.
D) The repair enzyme recognizes the removed nucleotide and brings in an identical one to replace it.
E) The three-dimensional structure determines the order of nucleotides.
22. Genetic foundations
Page: 30 Difficulty: 2 Ans: E
The three-dimensional structure of a protein is determined primarily by:
A) electrostatic guidance from nucleic acid structure.
B) how many amino acids are in the protein.
C) hydrophobic interaction with lipids that provide a folding framework.
D) modification during interactions with ribosomes.
E) the sequence of amino acids in the protein.
23. Evolutionary foundations
Page: 32 Difficulty: 2 Ans: D
According to Oparin's theory for the origin of life, the prebiotic atmosphere:
A) already contained some primitive RNA molecules.
B) basically was very similar to the atmosphere of today.
C) contained many amino acids.
D) had an abundance of methane, ammonia, and water.
E) was rich in oxygen.
,6 Chapter 1 The Foundations of Biochemistry
Short Answer Questions
24. Cellular foundations
Pages: 1-2 Difficulty: 1
What six characteristics distinguish living organisms from inanimate objects?
Ans: Living organisms (1) are chemically complex and highly organized; (2) extract, transform, and
use energy from their environment; (3) have the capacity to precisely self-replicate and self-assemble;
(4) exploit a chemical interplay with their environment; (5) possess programmatically defined
functions; and (6) evolve to new forms over many generations.
25. Cellular foundations
Page: 3 Difficulty: 1
All cells are surrounded by a plasma membrane composed of lipid and protein molecules. What is
the function of the plasma membrane?
Ans: The plasma membrane acts as a barrier to the free passage of inorganic ions and most other
charged or polar compounds into or out of the cell. It contains proteins that can transport specific
ions or molecules. Other membrane proteins act as receptors that transmit signals from the outside to
the inside of the cell.
26. Cellular foundations
Page: 6 Difficulty: 1
E. coli is known as a gram-negative bacterial species. (a) How is this determined? (b) How do gram-
negative bacteria differ structurally from gram-positive bacteria?
Ans: (a) Gram-negative bacteria have little affinity for the dye gentian violet used in Gram's stain, but
gram-positive bacteria retain Gram's stain. (b) Gram-negative bacteria have an outer membrane and a
peptidoglycan layer; gram-positive bacteria lack an outer membrane and the peptidoglycan layer is
much thicker.
27. Cellular foundations
Page: 7 Difficulty: 1
Most cells of higher plants have a cell wall outside the plasma membrane. What is the function of the
cell wall?
Ans: The cell wall provides a rigid, protective shell for the cell. It is porous, allowing water and
small molecules to pass readily, but it is rigid enough to resist the swelling of the cell caused by the
accumulation of water. (See Fig. 1-7, p. 7.)
28. Cellular foundations
Page: 11 Difficulty: 2
(a) List the types of noncovalent interactions that are important in providing stability to the three-
dimensional structures of macromolecules. (b) Why is it important that these interactions be
noncovalent, rather than covalent, bonds?
Ans: (a) Noncovalent interactions include hydrogen bonds, ionic interactions between charged
groups, van der Waals interactions, and hydrophobic interactions. (b) Because noncovalent
interactions are weak, they can form, break, and re-form more rapidly and with less energy input than
can covalent bonds. This is important to maintain the flexibility needed in macromolecules.
, Chapter 1 The Foundations of Biochemistry 7
29. Chemical foundations
Page: 14 Difficulty: 1
Draw the structures of the following functional groups in their un-ionized forms:
(a) hydroxyl, (b) carboxyl, (c) amino, (d) phosphoryl.
Ans:
30. Chemical foundations
Pages: 15-16 Difficulty: 2
What is the underlying, organizing biochemical principle that results in the chemical similarity of
virtually all living things? Given this biochemical similarity, how is the structural and functional
diversity of living things possible?
Ans: Living things are composed primarily of macromolecules, polymers of simple compounds of
just a few different types. The properties of these polymers are determined by their sequence of
monomers and these can be combined in many different ways. Diversity is thus achieved through the
nearly limitless variety of sequences that can exist when amino acids are linked to form proteins,
nucleotides are linked to form nucleic acids, and monosaccharides are linked to form polysaccharides.
Branching in the latter can contribute additional heterogeneity. Each type of organism constructs a
unique set of macromolecules from these monomeric units, resulting in the structural and functional
diversity among species.
31. Chemical foundations
Page: 16 Difficulty: 2
Name two functions of (a) proteins, (b) nucleic acids, (c) polysaccharides, (d) lipids.
Ans: Many answers are possible including: (a) proteins function as enzymes, structural elements,
signal carriers, transporters; (b) nucleic acids store and transmit genetic information and act as both
structural and catalytic elements; (c) polysaccharides serve as energy-yielding fuel stores and cellular
and extracellular structural and recognition elements, (d) lipids function as membrane components,
fuel stores, and cellular signals.
32. Chemical Foundations
Pages: 17-18 Difficulty: 2
Why is an asymmetric carbon atom called a chiral center?
Ans: An asymmetric carbon has four different substituents attached, and cannot be superimposed on
its mirror image—as a right hand cannot fit into a left glove. Thus a molecule with one chiral carbon
will have two stereoisomers, which may be distinguishable from one another in a biological system.
,
,
,
,Chapter 1 The Foundations of Biochemistry 3
10. Chemical foundations
Page: 14 Difficulty: 1 Ans: B
What functional groups are present on this molecule?
A) ether and aldehyde
B) hydroxyl and aldehyde
C) hydroxyl and carboxylic acid
D) hydroxyl and ester
E) hydroxyl and ketone
11. Chemical foundations
Page: 16 Difficulty: 1 Ans: D
The macromolecules that serve in the storage and transmission of genetic information are:
A) carbohydrates.
B) lipids.
C) membranes.
D) nucleic acids.
E) proteins.
12. Chemical foundations
Page: 17 Difficulty: 1 Ans: D
Stereoisomers that are nonsuperimposable mirror images of each other are known as:
A) anomers.
B) cis-trans isomers.
C) diastereoisomers.
D) enantiomers.
E) geometric isomers.
13. Chemical foundations
Page: 20 Difficulty: 3 Ans: E
The enzyme fumarase catalyzes the reversible hydration of fumaric acid to l-malate, but it will not
catalyze the hydration of maleic acid, the cis isomer of fumaric acid. This is an example of:
A) biological activity.
B) chiral activity.
C) racemization.
D) stereoisomerization.
E) stereospecificity.
,4 Chapter 1 The Foundations of Biochemistry
14. Physical foundations
Pages: 21-22 Difficulty: 2 Ans: A
Humans maintain a nearly constant level of hemoglobin by continually synthesizing and degrading it.
This is an example of a(n):
A) dynamic steady state.
B) equilibrium state.
C) exergonic change.
D) free-energy change.
E) waste of energy.
15. Physical foundations
Page: 23 Difficulty: 1 Ans: C
If heat energy is absorbed by the system during a chemical reaction, the reaction is said to be:
A) at equilibrium.
B) endergonic.
C) endothermic.
D) exergonic.
E) exothermic.
16. Physical foundations
Page: 23 Difficulty: 2 Ans: D
If the free energy change G for a reaction is -46.11 kJ/mol, the reaction is:
A) at equilibrium.
B) endergonic.
C) endothermic.
D) exergonic.
E) exothermic.
17. Physical foundations
Page: 23 Difficulty: 2 Ans: C
The major carrier of chemical energy in all cells is:
A) acetyl triphosphate.
B) adenosine monophosphate.
C) adenosine triphosphate.
D) cytosine tetraphosphate.
E) uridine diphosphate.
18. Physical foundations
Page: 26 Difficulty: 2 Ans: A
Enzymes are biological catalysts that enhance the rate of a reaction by:
A) decreasing the activation energy.
B) decreasing the amount of free energy released.
C) increasing the activation energy.
D) increasing the amount of free energy released.
E) increasing the energy of the transition state.
,Chapter 1 The Foundations of Biochemistry 5
19. Physical foundations
Page: 27 Difficulty: 1 Ans: B
Energy requiring metabolic pathways that yield complex molecules from simpler precursors are:
A) amphibolic.
B) anabolic.
C) autotrophic.
D) catabolic.
E) heterotrophic.
20. Genetic foundations
Page: 29 Difficulty: 1 Ans: A
Hereditary information (with the exception of some viruses) is preserved in:
A) deoxyribonucleic acid.
B) membrane structures.
C) nuclei.
D) polysaccharides.
E) ribonucleic acid.
21. Genetic foundations
Page: 29 Difficulty: 2 Ans: C
When a region of DNA must be repaired by removing and replacing some of the nucleotides, what
ensures that the new nucleotides are in the correct sequence?
A) DNA cannot be repaired and this explains why mutations occur.
B) Specific enzymes bind the correct nucleotides.
C) The new nucleotides basepair accurately with those on the complementary strand.
D) The repair enzyme recognizes the removed nucleotide and brings in an identical one to replace it.
E) The three-dimensional structure determines the order of nucleotides.
22. Genetic foundations
Page: 30 Difficulty: 2 Ans: E
The three-dimensional structure of a protein is determined primarily by:
A) electrostatic guidance from nucleic acid structure.
B) how many amino acids are in the protein.
C) hydrophobic interaction with lipids that provide a folding framework.
D) modification during interactions with ribosomes.
E) the sequence of amino acids in the protein.
23. Evolutionary foundations
Page: 32 Difficulty: 2 Ans: D
According to Oparin's theory for the origin of life, the prebiotic atmosphere:
A) already contained some primitive RNA molecules.
B) basically was very similar to the atmosphere of today.
C) contained many amino acids.
D) had an abundance of methane, ammonia, and water.
E) was rich in oxygen.
,6 Chapter 1 The Foundations of Biochemistry
Short Answer Questions
24. Cellular foundations
Pages: 1-2 Difficulty: 1
What six characteristics distinguish living organisms from inanimate objects?
Ans: Living organisms (1) are chemically complex and highly organized; (2) extract, transform, and
use energy from their environment; (3) have the capacity to precisely self-replicate and self-assemble;
(4) exploit a chemical interplay with their environment; (5) possess programmatically defined
functions; and (6) evolve to new forms over many generations.
25. Cellular foundations
Page: 3 Difficulty: 1
All cells are surrounded by a plasma membrane composed of lipid and protein molecules. What is
the function of the plasma membrane?
Ans: The plasma membrane acts as a barrier to the free passage of inorganic ions and most other
charged or polar compounds into or out of the cell. It contains proteins that can transport specific
ions or molecules. Other membrane proteins act as receptors that transmit signals from the outside to
the inside of the cell.
26. Cellular foundations
Page: 6 Difficulty: 1
E. coli is known as a gram-negative bacterial species. (a) How is this determined? (b) How do gram-
negative bacteria differ structurally from gram-positive bacteria?
Ans: (a) Gram-negative bacteria have little affinity for the dye gentian violet used in Gram's stain, but
gram-positive bacteria retain Gram's stain. (b) Gram-negative bacteria have an outer membrane and a
peptidoglycan layer; gram-positive bacteria lack an outer membrane and the peptidoglycan layer is
much thicker.
27. Cellular foundations
Page: 7 Difficulty: 1
Most cells of higher plants have a cell wall outside the plasma membrane. What is the function of the
cell wall?
Ans: The cell wall provides a rigid, protective shell for the cell. It is porous, allowing water and
small molecules to pass readily, but it is rigid enough to resist the swelling of the cell caused by the
accumulation of water. (See Fig. 1-7, p. 7.)
28. Cellular foundations
Page: 11 Difficulty: 2
(a) List the types of noncovalent interactions that are important in providing stability to the three-
dimensional structures of macromolecules. (b) Why is it important that these interactions be
noncovalent, rather than covalent, bonds?
Ans: (a) Noncovalent interactions include hydrogen bonds, ionic interactions between charged
groups, van der Waals interactions, and hydrophobic interactions. (b) Because noncovalent
interactions are weak, they can form, break, and re-form more rapidly and with less energy input than
can covalent bonds. This is important to maintain the flexibility needed in macromolecules.
, Chapter 1 The Foundations of Biochemistry 7
29. Chemical foundations
Page: 14 Difficulty: 1
Draw the structures of the following functional groups in their un-ionized forms:
(a) hydroxyl, (b) carboxyl, (c) amino, (d) phosphoryl.
Ans:
30. Chemical foundations
Pages: 15-16 Difficulty: 2
What is the underlying, organizing biochemical principle that results in the chemical similarity of
virtually all living things? Given this biochemical similarity, how is the structural and functional
diversity of living things possible?
Ans: Living things are composed primarily of macromolecules, polymers of simple compounds of
just a few different types. The properties of these polymers are determined by their sequence of
monomers and these can be combined in many different ways. Diversity is thus achieved through the
nearly limitless variety of sequences that can exist when amino acids are linked to form proteins,
nucleotides are linked to form nucleic acids, and monosaccharides are linked to form polysaccharides.
Branching in the latter can contribute additional heterogeneity. Each type of organism constructs a
unique set of macromolecules from these monomeric units, resulting in the structural and functional
diversity among species.
31. Chemical foundations
Page: 16 Difficulty: 2
Name two functions of (a) proteins, (b) nucleic acids, (c) polysaccharides, (d) lipids.
Ans: Many answers are possible including: (a) proteins function as enzymes, structural elements,
signal carriers, transporters; (b) nucleic acids store and transmit genetic information and act as both
structural and catalytic elements; (c) polysaccharides serve as energy-yielding fuel stores and cellular
and extracellular structural and recognition elements, (d) lipids function as membrane components,
fuel stores, and cellular signals.
32. Chemical Foundations
Pages: 17-18 Difficulty: 2
Why is an asymmetric carbon atom called a chiral center?
Ans: An asymmetric carbon has four different substituents attached, and cannot be superimposed on
its mirror image—as a right hand cannot fit into a left glove. Thus a molecule with one chiral carbon
will have two stereoisomers, which may be distinguishable from one another in a biological system.
