Test Bank for Biochemistry 9th Edition
Campbell / All Chapters 1 - 24 / Full
Complete
Chapter 1: Biochemistry and the Organization of Cells
1. How do biological molecules compare to molecules encountered in organic chemistry?
A) They are entirely different classes of compounds
B) Biological molecules are organic molecules that follow the same chemical principles
C) Biological molecules violate standard chemical rules
D) Only biological molecules contain carbon
Correct Answer: B
Rationale: Biological molecules are organic molecules and obey all standard chemical and
physical laws. The difference lies in their complexity and organization, not in fundamentally
different chemistry. The vital force theory, which proposed that living matter had special
properties, was dispelled by Wöhler's synthesis of urea.
2. Which order correctly represents increasing complexity?
A) Atom → molecule → macromolecule → organelle → cell
B) Molecule → atom → organelle → macromolecule → cell
C) Atom → organelle → molecule → macromolecule → cell
D) Macromolecule → atom → molecule → organelle → cell
Correct Answer: A
Rationale: The hierarchy of biological organization proceeds from simplest to most complex:
atoms combine to form molecules; molecules polymerize into macromolecules;
macromolecules assemble into organelles; organelles function within cells.
3. Which statement about the primitive Earth atmosphere is correct?
A) It contained abundant molecular oxygen
B) It was oxidizing and supported aerobic metabolism
C) It was reducing and lacked significant free oxygen
D) It contained only carbon dioxide and water
, Correct Answer: C
Rationale: The primitive atmosphere was reducing (or weakly reducing) with no significant
free oxygen. Oxygen appeared later as a product of photosynthesis by cyanobacteria during the
Great Oxidation Event.
4. The Miller-Urey experiment demonstrated that:
A) DNA is the genetic material
B) Simple organic compounds can form from inorganic gases under prebiotic conditions
C) Living cells can be created from non-living materials
D) Proteins are the first molecules of life
Correct Answer: B
Rationale: Miller and Urey showed that amino acids and other simple organic compounds
form when gases like methane, ammonia, hydrogen, and water vapor are subjected to electrical
discharges simulating lightning on early Earth.
5. (SATA) Which of the following are biological catalysts? Select all that apply.
A) Proteins
B) RNA
C) DNA
D) Lipids
E) Ribozymes
Correct Answers: A, B, E
Rationale: Most biological catalysts are proteins (enzymes), but certain RNA molecules
called ribozymes also catalyze reactions. DNA and lipids do not serve as biological catalysts.
6. The key structural difference between prokaryotic and eukaryotic cells is:
A) Presence of ribosomes
B) Presence of a membrane-bound nucleus
C) Type of genetic material
D) Presence of a cell membrane
Correct Answer: B
Rationale: Eukaryotes have a membrane-bound nucleus containing their DNA, while
,prokaryotes lack a true nucleus and keep their DNA in the nucleoid region. Both cell types have
ribosomes, DNA, and cell membranes.
Chapter 2: Water: The Solvent for Biochemical Reactions
7. Water's ability to dissolve ionic and polar substances is primarily due to:
A) Its low molecular weight
B) Its bent geometry and polar covalent bonds
C) Its high boiling point
D) Its ability to form ionic bonds
Correct Answer: B
Rationale: Water's bent shape creates a dipole moment: partial negative charge on oxygen
and partial positive charges on hydrogens. This polarity allows water to solvate ions and polar
molecules through ion-dipole and dipole-dipole interactions.
8. A hydrogen bond is best described as:
A) A covalent bond between hydrogen and oxygen
B) A strong ionic interaction
C) A dipole-dipole attraction involving a hydrogen bonded to an electronegative atom
D) A bond formed only between different molecules
Correct Answer: C
Rationale: Hydrogen bonds are special dipole-dipole attractions between a hydrogen
covalently bonded to N, O, or F and a lone pair on another electronegative atom. They can occur
within a single molecule (intramolecular) or between molecules (intermolecular).
9. According to the Henderson-Hasselbalch equation, a buffer has maximum capacity when:
A) pH = pKa
B) pH is two units above pKa
C) pH is two units below pKa
D) The acid concentration is zero
Correct Answer: A
Rationale: Buffer capacity is greatest when pH = pKa, at which point [A⁻] = [HA]. The
buffering region extends roughly ±1 pH unit from the pKa.
, 10. (SATA) Which statements about water are correct? Select all that apply.
A) Water has a high boiling point relative to its molecular weight
B) Water is a good solvent for nonpolar molecules
C) Water molecules are extensively hydrogen bonded
D) Water can act as both an acid and a base
E) The density of ice is greater than liquid water
Correct Answers: A, C, D
Rationale: Water's extensive hydrogen bonding explains its anomalously high boiling point.
Water is amphoteric (can donate or accept protons). Ice is less dense than liquid water because
hydrogen bonds form a open lattice structure.
11. Which interaction is strongest in aqueous solution?
A) Ionic bonds
B) Hydrogen bonds
C) Dipole-induced dipole
D) Induced dipole-induced dipole
Correct Answer: A
Rationale: From strongest to weakest in aqueous solution: ionic bonds > ion-dipole > dipole-
dipole (including hydrogen bonds) > dipole-induced dipole > induced dipole-induced dipole.
12. Nonphysiological buffers like HEPES and PIPES are commonly used because:
A) They are less expensive
B) They have less tendency to interfere with biological reactions
C) They contain nitrogen
D) They are naturally occurring
Correct Answer: B
Rationale: "Good" buffers such as HEPES and PIPES were designed to minimize interference
with biological processes. They have low membrane permeability, minimal metal binding, and
do not participate in enzymatic reactions.
Chapter 3: Amino Acids and Peptides
Campbell / All Chapters 1 - 24 / Full
Complete
Chapter 1: Biochemistry and the Organization of Cells
1. How do biological molecules compare to molecules encountered in organic chemistry?
A) They are entirely different classes of compounds
B) Biological molecules are organic molecules that follow the same chemical principles
C) Biological molecules violate standard chemical rules
D) Only biological molecules contain carbon
Correct Answer: B
Rationale: Biological molecules are organic molecules and obey all standard chemical and
physical laws. The difference lies in their complexity and organization, not in fundamentally
different chemistry. The vital force theory, which proposed that living matter had special
properties, was dispelled by Wöhler's synthesis of urea.
2. Which order correctly represents increasing complexity?
A) Atom → molecule → macromolecule → organelle → cell
B) Molecule → atom → organelle → macromolecule → cell
C) Atom → organelle → molecule → macromolecule → cell
D) Macromolecule → atom → molecule → organelle → cell
Correct Answer: A
Rationale: The hierarchy of biological organization proceeds from simplest to most complex:
atoms combine to form molecules; molecules polymerize into macromolecules;
macromolecules assemble into organelles; organelles function within cells.
3. Which statement about the primitive Earth atmosphere is correct?
A) It contained abundant molecular oxygen
B) It was oxidizing and supported aerobic metabolism
C) It was reducing and lacked significant free oxygen
D) It contained only carbon dioxide and water
, Correct Answer: C
Rationale: The primitive atmosphere was reducing (or weakly reducing) with no significant
free oxygen. Oxygen appeared later as a product of photosynthesis by cyanobacteria during the
Great Oxidation Event.
4. The Miller-Urey experiment demonstrated that:
A) DNA is the genetic material
B) Simple organic compounds can form from inorganic gases under prebiotic conditions
C) Living cells can be created from non-living materials
D) Proteins are the first molecules of life
Correct Answer: B
Rationale: Miller and Urey showed that amino acids and other simple organic compounds
form when gases like methane, ammonia, hydrogen, and water vapor are subjected to electrical
discharges simulating lightning on early Earth.
5. (SATA) Which of the following are biological catalysts? Select all that apply.
A) Proteins
B) RNA
C) DNA
D) Lipids
E) Ribozymes
Correct Answers: A, B, E
Rationale: Most biological catalysts are proteins (enzymes), but certain RNA molecules
called ribozymes also catalyze reactions. DNA and lipids do not serve as biological catalysts.
6. The key structural difference between prokaryotic and eukaryotic cells is:
A) Presence of ribosomes
B) Presence of a membrane-bound nucleus
C) Type of genetic material
D) Presence of a cell membrane
Correct Answer: B
Rationale: Eukaryotes have a membrane-bound nucleus containing their DNA, while
,prokaryotes lack a true nucleus and keep their DNA in the nucleoid region. Both cell types have
ribosomes, DNA, and cell membranes.
Chapter 2: Water: The Solvent for Biochemical Reactions
7. Water's ability to dissolve ionic and polar substances is primarily due to:
A) Its low molecular weight
B) Its bent geometry and polar covalent bonds
C) Its high boiling point
D) Its ability to form ionic bonds
Correct Answer: B
Rationale: Water's bent shape creates a dipole moment: partial negative charge on oxygen
and partial positive charges on hydrogens. This polarity allows water to solvate ions and polar
molecules through ion-dipole and dipole-dipole interactions.
8. A hydrogen bond is best described as:
A) A covalent bond between hydrogen and oxygen
B) A strong ionic interaction
C) A dipole-dipole attraction involving a hydrogen bonded to an electronegative atom
D) A bond formed only between different molecules
Correct Answer: C
Rationale: Hydrogen bonds are special dipole-dipole attractions between a hydrogen
covalently bonded to N, O, or F and a lone pair on another electronegative atom. They can occur
within a single molecule (intramolecular) or between molecules (intermolecular).
9. According to the Henderson-Hasselbalch equation, a buffer has maximum capacity when:
A) pH = pKa
B) pH is two units above pKa
C) pH is two units below pKa
D) The acid concentration is zero
Correct Answer: A
Rationale: Buffer capacity is greatest when pH = pKa, at which point [A⁻] = [HA]. The
buffering region extends roughly ±1 pH unit from the pKa.
, 10. (SATA) Which statements about water are correct? Select all that apply.
A) Water has a high boiling point relative to its molecular weight
B) Water is a good solvent for nonpolar molecules
C) Water molecules are extensively hydrogen bonded
D) Water can act as both an acid and a base
E) The density of ice is greater than liquid water
Correct Answers: A, C, D
Rationale: Water's extensive hydrogen bonding explains its anomalously high boiling point.
Water is amphoteric (can donate or accept protons). Ice is less dense than liquid water because
hydrogen bonds form a open lattice structure.
11. Which interaction is strongest in aqueous solution?
A) Ionic bonds
B) Hydrogen bonds
C) Dipole-induced dipole
D) Induced dipole-induced dipole
Correct Answer: A
Rationale: From strongest to weakest in aqueous solution: ionic bonds > ion-dipole > dipole-
dipole (including hydrogen bonds) > dipole-induced dipole > induced dipole-induced dipole.
12. Nonphysiological buffers like HEPES and PIPES are commonly used because:
A) They are less expensive
B) They have less tendency to interfere with biological reactions
C) They contain nitrogen
D) They are naturally occurring
Correct Answer: B
Rationale: "Good" buffers such as HEPES and PIPES were designed to minimize interference
with biological processes. They have low membrane permeability, minimal metal binding, and
do not participate in enzymatic reactions.
Chapter 3: Amino Acids and Peptides
