Portage Learning CHEM 210 Biochemistry
Exam Prep 2026/2027 | Exams 1–8 & Final
Exam Complete Study Guide with Verified
Answers
• This study guide covers all 8 Portage Learning CHEM 210 Biochemistry exams plus
the Final, giving you 200 verified practice questions with EXPERT RATIONALE to
reinforce deep understanding of every testable concept.
• Use this material by reading each question carefully, selecting your answer before
checking the correct option, then studying the EXPERT RATIONALE to solidify the
"why" behind each answer.
PORTAGE LEARNING CHEM 210 BIOCHEMISTRY Exam Prep 2026/2027 | Exams
1–8 & Final Exam 200 Practice Questions with Verified Answers & EXPERT
RATIONALE
1. What property of water makes it an excellent biological solvent?
A) Its high molecular weight
B) Its nonpolar covalent bonds
C) Its ability to form hydrogen bonds with polar and ionic solutes
D) Its low specific heat capacity
E) Its inability to ionize
C) Its ability to form hydrogen bonds with polar and ionic solutes
EXPERT RATIONALE: Water's polarity and hydrogen-bonding capacity allow it to
dissolve a wide variety of biological molecules, making it the universal solvent of
life.
2. Which of the following best describes a hydrogen bond?
A) A covalent bond between two hydrogen atoms
,B) An ionic attraction between hydrogen and a metal
C) A weak electrostatic attraction between a hydrogen atom bonded to an
electronegative atom and another electronegative atom
D) A strong bond formed when hydrogen loses an electron
E) A bond exclusive to water molecules only
C) A weak electrostatic attraction between a hydrogen atom bonded to an
electronegative atom and another electronegative atom
EXPERT RATIONALE: Hydrogen bonds form when hydrogen is covalently bonded
to N, O, or F and is attracted to another electronegative atom. They are weak
individually but collectively stabilize biological structures.
3. What is the pH of a solution with a hydrogen ion concentration of 1 × 10⁻⁷
M?
A) 3
B) 5
C) 9
D) 7
E) 11
D) 7
EXPERT RATIONALE: pH = −log[H⁺] = −log(1 × 10⁻⁷) = 7. This is the pH of pure water
at 25°C, considered neutral.
4. A buffer solution resists changes in pH because it:
A) Contains a strong acid and its conjugate base
B) Contains a weak acid and its conjugate base in equilibrium
C) Completely neutralizes all added acids or bases
,D) Has a very high pH
E) Dissociates completely in water
B) Contains a weak acid and its conjugate base in equilibrium
EXPERT RATIONALE: Buffers work by the reversible reaction between a weak acid
and its conjugate base, which absorbs added H⁺ or OH⁻ without significant pH
change.
5. The Henderson-Hasselbalch equation is:
A) pH = pKa × log([A⁻]/[HA])
B) pH = pKa + log([HA]/[A⁻])
C) pH = pKa + log([A⁻]/[HA])
D) pH = Ka − log([A⁻]/[HA])
E) pH = pKa − [A⁻]/[HA]
C) pH = pKa + log([A⁻]/[HA])
EXPERT RATIONALE: The Henderson-Hasselbalch equation relates pH to the pKa of
the weak acid and the ratio of conjugate base to weak acid, essential for buffer
calculations.
6. Which of the following is the primary biological buffer in human blood?
A) Phosphate buffer
B) Acetate buffer
C) Citrate buffer
D) Bicarbonate buffer
E) Sulfate buffer
D) Bicarbonate buffer
, EXPERT RATIONALE: The bicarbonate/carbonic acid system (HCO₃⁻/H₂CO₃) is the
principal extracellular buffer in blood, maintaining blood pH near 7.4.
7. When a solution has a pH below 7, it is considered:
A) Neutral
B) Basic
C) Alkaline
D) Acidic
E) Buffered
D) Acidic
EXPERT RATIONALE: A pH below 7 indicates a higher concentration of H⁺ ions than
OH⁻ ions, making the solution acidic.
8. The pKa of a weak acid is the pH at which:
A) The acid is fully dissociated
B) The concentration of the acid equals the concentration of its conjugate base
C) The solution is most basic
D) The acid has no buffering capacity
E) The conjugate base concentration is zero
B) The concentration of the acid equals the concentration of its conjugate
base
EXPERT RATIONALE: At pH = pKa, [HA] = [A⁻], so the log term in the Henderson-
Hasselbalch equation equals zero, and pH = pKa.
9. Which of the following statements about water is TRUE?
Exam Prep 2026/2027 | Exams 1–8 & Final
Exam Complete Study Guide with Verified
Answers
• This study guide covers all 8 Portage Learning CHEM 210 Biochemistry exams plus
the Final, giving you 200 verified practice questions with EXPERT RATIONALE to
reinforce deep understanding of every testable concept.
• Use this material by reading each question carefully, selecting your answer before
checking the correct option, then studying the EXPERT RATIONALE to solidify the
"why" behind each answer.
PORTAGE LEARNING CHEM 210 BIOCHEMISTRY Exam Prep 2026/2027 | Exams
1–8 & Final Exam 200 Practice Questions with Verified Answers & EXPERT
RATIONALE
1. What property of water makes it an excellent biological solvent?
A) Its high molecular weight
B) Its nonpolar covalent bonds
C) Its ability to form hydrogen bonds with polar and ionic solutes
D) Its low specific heat capacity
E) Its inability to ionize
C) Its ability to form hydrogen bonds with polar and ionic solutes
EXPERT RATIONALE: Water's polarity and hydrogen-bonding capacity allow it to
dissolve a wide variety of biological molecules, making it the universal solvent of
life.
2. Which of the following best describes a hydrogen bond?
A) A covalent bond between two hydrogen atoms
,B) An ionic attraction between hydrogen and a metal
C) A weak electrostatic attraction between a hydrogen atom bonded to an
electronegative atom and another electronegative atom
D) A strong bond formed when hydrogen loses an electron
E) A bond exclusive to water molecules only
C) A weak electrostatic attraction between a hydrogen atom bonded to an
electronegative atom and another electronegative atom
EXPERT RATIONALE: Hydrogen bonds form when hydrogen is covalently bonded
to N, O, or F and is attracted to another electronegative atom. They are weak
individually but collectively stabilize biological structures.
3. What is the pH of a solution with a hydrogen ion concentration of 1 × 10⁻⁷
M?
A) 3
B) 5
C) 9
D) 7
E) 11
D) 7
EXPERT RATIONALE: pH = −log[H⁺] = −log(1 × 10⁻⁷) = 7. This is the pH of pure water
at 25°C, considered neutral.
4. A buffer solution resists changes in pH because it:
A) Contains a strong acid and its conjugate base
B) Contains a weak acid and its conjugate base in equilibrium
C) Completely neutralizes all added acids or bases
,D) Has a very high pH
E) Dissociates completely in water
B) Contains a weak acid and its conjugate base in equilibrium
EXPERT RATIONALE: Buffers work by the reversible reaction between a weak acid
and its conjugate base, which absorbs added H⁺ or OH⁻ without significant pH
change.
5. The Henderson-Hasselbalch equation is:
A) pH = pKa × log([A⁻]/[HA])
B) pH = pKa + log([HA]/[A⁻])
C) pH = pKa + log([A⁻]/[HA])
D) pH = Ka − log([A⁻]/[HA])
E) pH = pKa − [A⁻]/[HA]
C) pH = pKa + log([A⁻]/[HA])
EXPERT RATIONALE: The Henderson-Hasselbalch equation relates pH to the pKa of
the weak acid and the ratio of conjugate base to weak acid, essential for buffer
calculations.
6. Which of the following is the primary biological buffer in human blood?
A) Phosphate buffer
B) Acetate buffer
C) Citrate buffer
D) Bicarbonate buffer
E) Sulfate buffer
D) Bicarbonate buffer
, EXPERT RATIONALE: The bicarbonate/carbonic acid system (HCO₃⁻/H₂CO₃) is the
principal extracellular buffer in blood, maintaining blood pH near 7.4.
7. When a solution has a pH below 7, it is considered:
A) Neutral
B) Basic
C) Alkaline
D) Acidic
E) Buffered
D) Acidic
EXPERT RATIONALE: A pH below 7 indicates a higher concentration of H⁺ ions than
OH⁻ ions, making the solution acidic.
8. The pKa of a weak acid is the pH at which:
A) The acid is fully dissociated
B) The concentration of the acid equals the concentration of its conjugate base
C) The solution is most basic
D) The acid has no buffering capacity
E) The conjugate base concentration is zero
B) The concentration of the acid equals the concentration of its conjugate
base
EXPERT RATIONALE: At pH = pKa, [HA] = [A⁻], so the log term in the Henderson-
Hasselbalch equation equals zero, and pH = pKa.
9. Which of the following statements about water is TRUE?
