WGU C190 PRE-ASSESSMENT EXAMINATION
Introduction to Biology
Q/A Review Guide
Comprehensive 60-question practice examination covering all core competency
areas: biological chemistry, cell structure and function, metabolism and energy,
cell division and genetics, molecular biology, and evolutionary ecology. Aligned
with 2026/2027 WGU C190 assessment standards.
60 Multiple-Choice Questions | Verified Answers
Latest 2026/2027 Update | 100% Correct
6 Content Sections | Detailed Rationales
P R E PA R E D F O R W G U C 1 9 0 C O U R S E E X A M I N A T I O N
,WGU C190 Pre-Assessment V2 (Latest 2026/2027
Update)
Introduction to Biology | Q/A | 100% Correct (Verified Answers)
Section 1: Basic Chemistry and Biological Molecules
Atoms, Bonds, Water, pH, and Macromolecules (Carbohydrates, Lipids, Proteins, Nucleic Acids)
Q1: An atom of sodium (Na) has 11 protons, 11 electrons, and 12 neutrons. What is its mass number and
atomic number, respectively?
A. 23 and 12
B. 12 and 11
C. 23 and 11
D. 11 and 23
Correct Answer: C
Rationale: The mass number is the sum of protons and neutrons (11 + 12 = 23), while the atomic number equals the number of
protons (11). This fundamental distinction is essential for understanding isotopes and nuclear notation in introductory biology
and chemistry.
Q2: Carbon-14 and carbon-12 are both isotopes of carbon. Which of the following correctly describes the
difference between them?
A. Carbon-14 has two more protons than carbon-12
B. Carbon-14 has two more neutrons than carbon-12
C. Carbon-14 has two more electrons than carbon-12
D. Carbon-14 has a different atomic number than carbon-12
Correct Answer: B
Rationale: Isotopes of an element have the same number of protons (atomic number) but differ in the number of neutrons,
giving them different mass numbers. Carbon-14 has 8 neutrons while carbon-12 has 6, which is why carbon-14 is used in
radioactive dating of organic materials.
Q3: A researcher observes that water molecules cling to the sides of a glass tube and to each other. Which
properties of water best explain these observations, respectively?
A. Cohesion and adhesion
B. Adhesion and cohesion
C. Surface tension and high specific heat
D. High heat of vaporization and universal solvent properties
Correct Answer: B
Rationale: Adhesion is the attraction between water molecules and other substances (clinging to glass), while cohesion is the
attraction between water molecules themselves (clinging to each other). Together, these properties enable capillary action, which
is critical for water transport in plants through xylem vessels.
Q4: A solution with a pH of 3 is how many times more acidic than a solution with a pH of 6?
, A. 2 times
B. 3 times
C. 100 times
D. 1,000 times
Correct Answer: D
Rationale: The pH scale is logarithmic, meaning each whole number change represents a tenfold difference in hydrogen ion
concentration. A difference of 3 pH units (6 - 3 = 3) corresponds to a 10 x 10 x 10 = 1,000-fold difference, making the pH 3
solution 1,000 times more acidic.
Q5: Which of the following polysaccharides functions primarily as a structural component in plant cell
walls and is composed of beta-glucose monomers linked by glycosidic bonds?
A. Starch
B. Glycogen
C. Cellulose
D. Chitin
Correct Answer: C
Rationale: Cellulose is a structural polysaccharide made of beta-glucose monomers joined by beta-1,4-glycosidic bonds,
forming long, straight chains that hydrogen-bond into strong microfibrils. Humans lack the enzyme cellulase to break these
bonds, making cellulose indigestible dietary fiber.
Q6: A triglyceride that contains no carbon-carbon double bonds in its fatty acid tails is classified as which
of the following?
A. Unsaturated fat
B. Polyunsaturated fat
C. Saturated fat
D. Trans fat
Correct Answer: C
Rationale: Saturated fatty acids have no double bonds between carbon atoms, meaning each carbon is fully saturated with
hydrogen atoms. This allows them to pack tightly together, forming solid fats at room temperature, whereas unsaturated fats
have kinks from double bonds that prevent tight packing.
Q7: Which type of bond is responsible for the primary structure of a protein and links amino acids
together in a specific sequence?
A. Hydrogen bond
B. Peptide bond
C. Disulfide bridge
D. Ionic bond
Correct Answer: B
Rationale: Peptide bonds form through a dehydration synthesis reaction between the carboxyl group of one amino acid and the
amino group of another, creating the linear sequence that defines a protein's primary structure. The specific order of amino
acids determines how the protein will fold into its functional three-dimensional shape.
Q8: The alpha helix and beta sheet are examples of which level of protein structure?
A. Primary structure
B. Secondary structure
C. Tertiary structure
D. Quaternary structure
Correct Answer: B
Introduction to Biology
Q/A Review Guide
Comprehensive 60-question practice examination covering all core competency
areas: biological chemistry, cell structure and function, metabolism and energy,
cell division and genetics, molecular biology, and evolutionary ecology. Aligned
with 2026/2027 WGU C190 assessment standards.
60 Multiple-Choice Questions | Verified Answers
Latest 2026/2027 Update | 100% Correct
6 Content Sections | Detailed Rationales
P R E PA R E D F O R W G U C 1 9 0 C O U R S E E X A M I N A T I O N
,WGU C190 Pre-Assessment V2 (Latest 2026/2027
Update)
Introduction to Biology | Q/A | 100% Correct (Verified Answers)
Section 1: Basic Chemistry and Biological Molecules
Atoms, Bonds, Water, pH, and Macromolecules (Carbohydrates, Lipids, Proteins, Nucleic Acids)
Q1: An atom of sodium (Na) has 11 protons, 11 electrons, and 12 neutrons. What is its mass number and
atomic number, respectively?
A. 23 and 12
B. 12 and 11
C. 23 and 11
D. 11 and 23
Correct Answer: C
Rationale: The mass number is the sum of protons and neutrons (11 + 12 = 23), while the atomic number equals the number of
protons (11). This fundamental distinction is essential for understanding isotopes and nuclear notation in introductory biology
and chemistry.
Q2: Carbon-14 and carbon-12 are both isotopes of carbon. Which of the following correctly describes the
difference between them?
A. Carbon-14 has two more protons than carbon-12
B. Carbon-14 has two more neutrons than carbon-12
C. Carbon-14 has two more electrons than carbon-12
D. Carbon-14 has a different atomic number than carbon-12
Correct Answer: B
Rationale: Isotopes of an element have the same number of protons (atomic number) but differ in the number of neutrons,
giving them different mass numbers. Carbon-14 has 8 neutrons while carbon-12 has 6, which is why carbon-14 is used in
radioactive dating of organic materials.
Q3: A researcher observes that water molecules cling to the sides of a glass tube and to each other. Which
properties of water best explain these observations, respectively?
A. Cohesion and adhesion
B. Adhesion and cohesion
C. Surface tension and high specific heat
D. High heat of vaporization and universal solvent properties
Correct Answer: B
Rationale: Adhesion is the attraction between water molecules and other substances (clinging to glass), while cohesion is the
attraction between water molecules themselves (clinging to each other). Together, these properties enable capillary action, which
is critical for water transport in plants through xylem vessels.
Q4: A solution with a pH of 3 is how many times more acidic than a solution with a pH of 6?
, A. 2 times
B. 3 times
C. 100 times
D. 1,000 times
Correct Answer: D
Rationale: The pH scale is logarithmic, meaning each whole number change represents a tenfold difference in hydrogen ion
concentration. A difference of 3 pH units (6 - 3 = 3) corresponds to a 10 x 10 x 10 = 1,000-fold difference, making the pH 3
solution 1,000 times more acidic.
Q5: Which of the following polysaccharides functions primarily as a structural component in plant cell
walls and is composed of beta-glucose monomers linked by glycosidic bonds?
A. Starch
B. Glycogen
C. Cellulose
D. Chitin
Correct Answer: C
Rationale: Cellulose is a structural polysaccharide made of beta-glucose monomers joined by beta-1,4-glycosidic bonds,
forming long, straight chains that hydrogen-bond into strong microfibrils. Humans lack the enzyme cellulase to break these
bonds, making cellulose indigestible dietary fiber.
Q6: A triglyceride that contains no carbon-carbon double bonds in its fatty acid tails is classified as which
of the following?
A. Unsaturated fat
B. Polyunsaturated fat
C. Saturated fat
D. Trans fat
Correct Answer: C
Rationale: Saturated fatty acids have no double bonds between carbon atoms, meaning each carbon is fully saturated with
hydrogen atoms. This allows them to pack tightly together, forming solid fats at room temperature, whereas unsaturated fats
have kinks from double bonds that prevent tight packing.
Q7: Which type of bond is responsible for the primary structure of a protein and links amino acids
together in a specific sequence?
A. Hydrogen bond
B. Peptide bond
C. Disulfide bridge
D. Ionic bond
Correct Answer: B
Rationale: Peptide bonds form through a dehydration synthesis reaction between the carboxyl group of one amino acid and the
amino group of another, creating the linear sequence that defines a protein's primary structure. The specific order of amino
acids determines how the protein will fold into its functional three-dimensional shape.
Q8: The alpha helix and beta sheet are examples of which level of protein structure?
A. Primary structure
B. Secondary structure
C. Tertiary structure
D. Quaternary structure
Correct Answer: B
