WGU C785 – COMPREHENSIVE QUESTIONS
AND ANSWERS | VERIFIED AND WELLDETAILED ANSWERS | DETAILED EXPLANATIONS AND
RATIONALES | COMPLETE EXAM PREPARATION STUDY GUIDE | PRACTICE QUESTIONS |
LATEST EXAM UPDATE
•
CORE DOMAINS
• Molecular Structure and Chemical Principles
• Cell Structure, Function, and Biological Organization
• DNA Structure, Replication, and Repair
• RNA Structure, Transcription, and RNA Processing
• Gene Regulation and Epigenetics
• Translation, Protein Structure, and Protein Function
• Mutation, Genetic Variation, and Molecular Techniques
• Cell Signaling, Cell Cycle, and Cancer Biology
• Biotechnology and Molecular Biology Applications
•
INTRODUCTION
This comprehensive assessment is designed to reinforce the molecular biology knowledge
and application skills relevant to WGU C785. The questions assess foundational principles,
terminology, molecular mechanisms, experimental concepts, and the relationships among
DNA, RNA, proteins, cells, and biological processes. Multiple-choice questions are used to
practice distinguishing closely related concepts, interpreting molecular scenarios, applying
biological principles, and evaluating experimental outcomes. Understanding the underlying
mechanisms—not simply memorizing terminology—is essential because molecular biology
concepts are interconnected. The assessment progressively incorporates foundational,
intermediate, advanced, and application-oriented questions to support focused examination
preparation and deeper understanding of molecular processes.
SECTION ONE: QUESTIONS 1–100
Question 1. Which statement best describes the central dogma of molecular biology?
A. Proteins are converted directly into DNA during cell division.
B. Genetic information generally flows from DNA to RNA to protein.
C. RNA is always converted into DNA before proteins are produced.
D. Proteins provide the template for producing RNA.
Correct Answer: B. Genetic information generally flows from DNA to RNA to protein
,Explanation: The central dogma describes the primary directional flow of genetic
information from DNA through RNA to protein. DNA is transcribed into RNA, and RNA can
then be translated into a polypeptide.
Question 2. Which type of bond links individual nucleotides together within a single strand
of DNA?
A. Hydrogen bond
B. Peptide bond
C. Phosphodiester bond
D. Ionic bond
Correct Answer: C. Phosphodiester bond
Explanation: Phosphodiester bonds connect the 3′ hydroxyl group of one nucleotide's sugar
to the 5′ phosphate group of the next nucleotide. Hydrogen bonds instead stabilize
interactions between complementary bases on opposite DNA strands.
Question 3. Which nitrogenous bases are classified as purines?
A. Cytosine and thymine
B. Adenine and guanine
C. Thymine and uracil
D. Cytosine and uracil
Correct Answer: B. Adenine and guanine
Explanation: Adenine and guanine are purines, which contain two fused rings. Cytosine,
thymine, and uracil are pyrimidines and contain a single six-membered ring.
Question 4. What characteristic of water contributes most directly to its ability to dissolve
many ionic and polar substances?
A. Its nonpolar nature
B. Its low specific heat
C. Its molecular symmetry
D. Its polarity
Correct Answer: D. Its polarity
Explanation: Water has an uneven distribution of electrical charge, making it polar. Its
partially positive and partially negative regions interact with ions and polar molecules,
allowing many substances to dissolve.
Question 5. A solution changes from pH 7 to pH 5. Approximately how does the hydrogen
ion concentration change?
, A. It decreases 100-fold.
B. It increases 100-fold.
C. It increases 2-fold.
D. It decreases 2-fold.
Correct Answer: B. It increases 100-fold.
Explanation: The pH scale is logarithmic. A decrease of two pH units corresponds to a 10², or
100-fold, increase in hydrogen ion concentration.
Question 6. Which functional group is characteristic of amino acids and contributes to
their ability to act as bases?
A. Hydroxyl group
B. Carbonyl group
C. Amino group
D. Phosphate group
Correct Answer: C. Amino group
Explanation: The amino group can accept a proton and therefore can behave as a base.
Amino acids also contain a carboxyl group, which can donate a proton and behave as an
acid.
Question 7. Which interaction is primarily responsible for maintaining the complementary
association between the two DNA strands?
A. Peptide bonding
B. Hydrogen bonding between complementary bases
C. Phosphodiester bonding between opposite strands
D. Disulfide bonding
Correct Answer: B. Hydrogen bonding between complementary bases
Explanation: Hydrogen bonds form between complementary nitrogenous bases: adenine
pairs with thymine, while guanine pairs with cytosine. The sugar-phosphate backbones of
the two strands are not directly joined by phosphodiester bonds.
Question 8. Which DNA base pairing is correct?
A. A–C and G–T
B. A–G and C–T
C. A–T and G–C
D. A–U and G–C
Correct Answer: C. A–T and G–C
AND ANSWERS | VERIFIED AND WELLDETAILED ANSWERS | DETAILED EXPLANATIONS AND
RATIONALES | COMPLETE EXAM PREPARATION STUDY GUIDE | PRACTICE QUESTIONS |
LATEST EXAM UPDATE
•
CORE DOMAINS
• Molecular Structure and Chemical Principles
• Cell Structure, Function, and Biological Organization
• DNA Structure, Replication, and Repair
• RNA Structure, Transcription, and RNA Processing
• Gene Regulation and Epigenetics
• Translation, Protein Structure, and Protein Function
• Mutation, Genetic Variation, and Molecular Techniques
• Cell Signaling, Cell Cycle, and Cancer Biology
• Biotechnology and Molecular Biology Applications
•
INTRODUCTION
This comprehensive assessment is designed to reinforce the molecular biology knowledge
and application skills relevant to WGU C785. The questions assess foundational principles,
terminology, molecular mechanisms, experimental concepts, and the relationships among
DNA, RNA, proteins, cells, and biological processes. Multiple-choice questions are used to
practice distinguishing closely related concepts, interpreting molecular scenarios, applying
biological principles, and evaluating experimental outcomes. Understanding the underlying
mechanisms—not simply memorizing terminology—is essential because molecular biology
concepts are interconnected. The assessment progressively incorporates foundational,
intermediate, advanced, and application-oriented questions to support focused examination
preparation and deeper understanding of molecular processes.
SECTION ONE: QUESTIONS 1–100
Question 1. Which statement best describes the central dogma of molecular biology?
A. Proteins are converted directly into DNA during cell division.
B. Genetic information generally flows from DNA to RNA to protein.
C. RNA is always converted into DNA before proteins are produced.
D. Proteins provide the template for producing RNA.
Correct Answer: B. Genetic information generally flows from DNA to RNA to protein
,Explanation: The central dogma describes the primary directional flow of genetic
information from DNA through RNA to protein. DNA is transcribed into RNA, and RNA can
then be translated into a polypeptide.
Question 2. Which type of bond links individual nucleotides together within a single strand
of DNA?
A. Hydrogen bond
B. Peptide bond
C. Phosphodiester bond
D. Ionic bond
Correct Answer: C. Phosphodiester bond
Explanation: Phosphodiester bonds connect the 3′ hydroxyl group of one nucleotide's sugar
to the 5′ phosphate group of the next nucleotide. Hydrogen bonds instead stabilize
interactions between complementary bases on opposite DNA strands.
Question 3. Which nitrogenous bases are classified as purines?
A. Cytosine and thymine
B. Adenine and guanine
C. Thymine and uracil
D. Cytosine and uracil
Correct Answer: B. Adenine and guanine
Explanation: Adenine and guanine are purines, which contain two fused rings. Cytosine,
thymine, and uracil are pyrimidines and contain a single six-membered ring.
Question 4. What characteristic of water contributes most directly to its ability to dissolve
many ionic and polar substances?
A. Its nonpolar nature
B. Its low specific heat
C. Its molecular symmetry
D. Its polarity
Correct Answer: D. Its polarity
Explanation: Water has an uneven distribution of electrical charge, making it polar. Its
partially positive and partially negative regions interact with ions and polar molecules,
allowing many substances to dissolve.
Question 5. A solution changes from pH 7 to pH 5. Approximately how does the hydrogen
ion concentration change?
, A. It decreases 100-fold.
B. It increases 100-fold.
C. It increases 2-fold.
D. It decreases 2-fold.
Correct Answer: B. It increases 100-fold.
Explanation: The pH scale is logarithmic. A decrease of two pH units corresponds to a 10², or
100-fold, increase in hydrogen ion concentration.
Question 6. Which functional group is characteristic of amino acids and contributes to
their ability to act as bases?
A. Hydroxyl group
B. Carbonyl group
C. Amino group
D. Phosphate group
Correct Answer: C. Amino group
Explanation: The amino group can accept a proton and therefore can behave as a base.
Amino acids also contain a carboxyl group, which can donate a proton and behave as an
acid.
Question 7. Which interaction is primarily responsible for maintaining the complementary
association between the two DNA strands?
A. Peptide bonding
B. Hydrogen bonding between complementary bases
C. Phosphodiester bonding between opposite strands
D. Disulfide bonding
Correct Answer: B. Hydrogen bonding between complementary bases
Explanation: Hydrogen bonds form between complementary nitrogenous bases: adenine
pairs with thymine, while guanine pairs with cytosine. The sugar-phosphate backbones of
the two strands are not directly joined by phosphodiester bonds.
Question 8. Which DNA base pairing is correct?
A. A–C and G–T
B. A–G and C–T
C. A–T and G–C
D. A–U and G–C
Correct Answer: C. A–T and G–C
