WGU C785 BIOCHEMISTRY UNIT EXAM QUESTIONS
& ANSWERS LATEST 2026/2027 WITH COMPLETE
SOLUTION
WGU C785 Biochemistry Comprehensive Practice Exam — 2026/2027
Western Governors University
Course: C785 — Biochemistry
Institution: Western Governors University
Exam Type: Comprehensive Original Practice Exam with Answers and Rationales
Date: August 13, 2026
Coverage: Biochemical systems, biomolecules, enzymes, metabolism, molecular
biology, genetics, cellular energetics, and laboratory concepts
Questions: 105
Format: Multiple-choice and short-answer
Important: This is an original study/practice examination.
Table of Contents
1. Section I — Biochemical Foundations and Water: Questions 1–15
2. Section II — Carbohydrates and Lipids: Questions 16–30
3. Section III — Amino Acids, Proteins, and Protein Structure: Questions 31–45
4. Section IV — Enzymes and Enzyme Kinetics: Questions 46–60
5. Section V — Cellular Respiration and Bioenergetics: Questions 61–75
6. Section VI — Molecular Biology and Gene Expression: Questions 76–90
7. Section VII — Integrated Metabolism, Regulation, and Laboratory Concepts: Questions
91–105
8. Answer Key Summary
Section I — Biochemical Foundations and Water
Question 1 — Multiple Choice
,Which property of water is primarily responsible for its ability to dissolve many ionic and polar
substances?
A. Low specific heat
B. Polarity
C. Low boiling point
D. Nonpolar covalent bonding
Correct answer: B. Polarity
Rationale: Water has an uneven distribution of electrical charge because oxygen is more
electronegative than hydrogen. This polarity allows water molecules to surround ions and
interact with other polar molecules, making water an excellent solvent for many biological
substances.
Question 2 — Multiple Choice
Which interaction is primarily responsible for holding complementary DNA bases together?
A. Peptide bonds
B. Ionic bonds
C. Hydrogen bonds
D. Disulfide bonds
Correct answer: C. Hydrogen bonds
Rationale: Adenine pairs with thymine through hydrogen bonds, while guanine pairs with
cytosine through hydrogen bonds. These interactions stabilize the DNA double helix while
remaining weak enough to permit strand separation during replication and transcription.
Question 3 — Short Answer
What is the difference between a covalent bond and a hydrogen bond?
Correct answer: A covalent bond involves sharing electrons between atoms, whereas a
hydrogen bond is a relatively weak electrostatic attraction between a partially positive hydrogen
atom and an electronegative atom.
Rationale: Covalent bonds are strong chemical bonds that form the backbone of biological
molecules. Hydrogen bonds are weaker individually but become biologically important when
many occur together, such as in DNA base pairing and protein secondary structure.
,Question 4 — Multiple Choice
A solution with a pH of 3 is how many times more acidic than a solution with a pH of 5?
A. 2 times
B. 10 times
C. 100 times
D. 1,000 times
Correct answer: C. 100 times
Rationale: The pH scale is logarithmic. A difference of two pH units represents a 10², or 100-
fold, difference in hydrogen-ion concentration.
Question 5 — Multiple Choice
Which molecule can act as a buffer by accepting or donating hydrogen ions?
A. ATP only
B. A weak acid/base conjugate pair
C. Molecular oxygen
D. Cholesterol
Correct answer: B. A weak acid/base conjugate pair
Rationale: Buffers resist changes in pH by accepting excess H⁺ or donating H⁺ when
concentrations decrease. Biological buffers commonly consist of weak acids and their conjugate
bases.
Question 6 — Short Answer
Define pH.
Correct answer: pH is the negative logarithm of the hydrogen-ion concentration of a solution:
pH = −log[H⁺].
Rationale: Because the relationship is logarithmic, a one-unit change in pH corresponds to a
tenfold change in hydrogen-ion concentration.
Question 7 — Multiple Choice
Which element is present in carbohydrates, lipids, proteins, and nucleic acids?
, A. Carbon
B. Sodium
C. Calcium
D. Chloride
Correct answer: A. Carbon
Rationale: Carbon is the central structural element of organic molecules. Its ability to form four
covalent bonds allows the formation of diverse biological structures.
Question 8 — Multiple Choice
Which macromolecule contains nitrogen as a characteristic component?
A. Proteins
B. Simple triglycerides only
C. Most carbohydrates
D. Water
Correct answer: A. Proteins
Rationale: Amino acids contain amino groups containing nitrogen. Proteins are polymers of
amino acids and therefore characteristically contain nitrogen.
Question 9 — Short Answer
What is an isomer?
Correct answer: An isomer is a molecule that has the same molecular formula as another
molecule but differs in the arrangement of its atoms.
Rationale: Different atomic arrangements can produce molecules with substantially different
structures and biological properties.
Question 10 — Multiple Choice
Which type of reaction joins monomers into a larger polymer while releasing water?
A. Hydrolysis
B. Dehydration synthesis
C. Oxidation
D. Reduction
& ANSWERS LATEST 2026/2027 WITH COMPLETE
SOLUTION
WGU C785 Biochemistry Comprehensive Practice Exam — 2026/2027
Western Governors University
Course: C785 — Biochemistry
Institution: Western Governors University
Exam Type: Comprehensive Original Practice Exam with Answers and Rationales
Date: August 13, 2026
Coverage: Biochemical systems, biomolecules, enzymes, metabolism, molecular
biology, genetics, cellular energetics, and laboratory concepts
Questions: 105
Format: Multiple-choice and short-answer
Important: This is an original study/practice examination.
Table of Contents
1. Section I — Biochemical Foundations and Water: Questions 1–15
2. Section II — Carbohydrates and Lipids: Questions 16–30
3. Section III — Amino Acids, Proteins, and Protein Structure: Questions 31–45
4. Section IV — Enzymes and Enzyme Kinetics: Questions 46–60
5. Section V — Cellular Respiration and Bioenergetics: Questions 61–75
6. Section VI — Molecular Biology and Gene Expression: Questions 76–90
7. Section VII — Integrated Metabolism, Regulation, and Laboratory Concepts: Questions
91–105
8. Answer Key Summary
Section I — Biochemical Foundations and Water
Question 1 — Multiple Choice
,Which property of water is primarily responsible for its ability to dissolve many ionic and polar
substances?
A. Low specific heat
B. Polarity
C. Low boiling point
D. Nonpolar covalent bonding
Correct answer: B. Polarity
Rationale: Water has an uneven distribution of electrical charge because oxygen is more
electronegative than hydrogen. This polarity allows water molecules to surround ions and
interact with other polar molecules, making water an excellent solvent for many biological
substances.
Question 2 — Multiple Choice
Which interaction is primarily responsible for holding complementary DNA bases together?
A. Peptide bonds
B. Ionic bonds
C. Hydrogen bonds
D. Disulfide bonds
Correct answer: C. Hydrogen bonds
Rationale: Adenine pairs with thymine through hydrogen bonds, while guanine pairs with
cytosine through hydrogen bonds. These interactions stabilize the DNA double helix while
remaining weak enough to permit strand separation during replication and transcription.
Question 3 — Short Answer
What is the difference between a covalent bond and a hydrogen bond?
Correct answer: A covalent bond involves sharing electrons between atoms, whereas a
hydrogen bond is a relatively weak electrostatic attraction between a partially positive hydrogen
atom and an electronegative atom.
Rationale: Covalent bonds are strong chemical bonds that form the backbone of biological
molecules. Hydrogen bonds are weaker individually but become biologically important when
many occur together, such as in DNA base pairing and protein secondary structure.
,Question 4 — Multiple Choice
A solution with a pH of 3 is how many times more acidic than a solution with a pH of 5?
A. 2 times
B. 10 times
C. 100 times
D. 1,000 times
Correct answer: C. 100 times
Rationale: The pH scale is logarithmic. A difference of two pH units represents a 10², or 100-
fold, difference in hydrogen-ion concentration.
Question 5 — Multiple Choice
Which molecule can act as a buffer by accepting or donating hydrogen ions?
A. ATP only
B. A weak acid/base conjugate pair
C. Molecular oxygen
D. Cholesterol
Correct answer: B. A weak acid/base conjugate pair
Rationale: Buffers resist changes in pH by accepting excess H⁺ or donating H⁺ when
concentrations decrease. Biological buffers commonly consist of weak acids and their conjugate
bases.
Question 6 — Short Answer
Define pH.
Correct answer: pH is the negative logarithm of the hydrogen-ion concentration of a solution:
pH = −log[H⁺].
Rationale: Because the relationship is logarithmic, a one-unit change in pH corresponds to a
tenfold change in hydrogen-ion concentration.
Question 7 — Multiple Choice
Which element is present in carbohydrates, lipids, proteins, and nucleic acids?
, A. Carbon
B. Sodium
C. Calcium
D. Chloride
Correct answer: A. Carbon
Rationale: Carbon is the central structural element of organic molecules. Its ability to form four
covalent bonds allows the formation of diverse biological structures.
Question 8 — Multiple Choice
Which macromolecule contains nitrogen as a characteristic component?
A. Proteins
B. Simple triglycerides only
C. Most carbohydrates
D. Water
Correct answer: A. Proteins
Rationale: Amino acids contain amino groups containing nitrogen. Proteins are polymers of
amino acids and therefore characteristically contain nitrogen.
Question 9 — Short Answer
What is an isomer?
Correct answer: An isomer is a molecule that has the same molecular formula as another
molecule but differs in the arrangement of its atoms.
Rationale: Different atomic arrangements can produce molecules with substantially different
structures and biological properties.
Question 10 — Multiple Choice
Which type of reaction joins monomers into a larger polymer while releasing water?
A. Hydrolysis
B. Dehydration synthesis
C. Oxidation
D. Reduction
