W E STE RN G OVE RN ORS U N IVE RSITY
WGU C190 Introduction to
Biology
Objective Assessment
100 Questions and Answers with Rationale
Aligned with WGU C190 Course Competencies and Exam
Blueprint
Chemistry of Life, Cell Biology, Genetics, Evolution,
Ecology
Q UEST I O N S SECT I O N S F O R M AT EDIT IO N
100 7 MCQ LATEST
100% CORRECT VERIFIED ANSWERS
,WGU C190 Introduction to Biology Objective Assessment 2026/2027 100 Questions | 100% Verified Answers
Section 1: Chemistry of Life
Q1: A biologist analyzes a newly discovered mineral spring and finds that the water contains an element with 8
protons, 8 neutrons, and 10 electrons. What is the charge of this ion, and which element is it?
A. It is oxygen with a 2- charge [CORRECT]
B. It is neon with a 2- charge
C. It is oxygen with a 2+ charge
D. It is fluorine with a 1- charge
Correct Answer: A
Rationale: The number of protons (8) identifies the element as oxygen. With 10 electrons versus 8 protons, there is an excess of 2
electrons, giving the ion a net charge of 2-.
Q2: A researcher is studying how table salt (NaCl) dissolves in water. Sodium donates an electron to chlorine,
forming Na+ and Cl- ions. What type of chemical bond is formed between sodium and chlorine in the solid crystal of
NaCl?
A. Nonpolar covalent bond
B. Ionic bond [CORRECT]
C. Hydrogen bond
D. Polar covalent bond
Correct Answer: B
Rationale: An ionic bond forms when one atom transfers one or more electrons to another atom, creating oppositely charged ions
that are held together by electrostatic attraction. Sodium losing an electron to chlorine is a classic example of ionic bonding.
Q3: During a hot summer day, a plant transports water from its roots to its leaves, even though the tallest trees are
over 100 feet tall. Which property of water is most directly responsible for this ability?
A. High specific heat capacity
B. Adhesion of water to the vessel walls
C. Cohesion of water molecules and adhesion to vessel walls working together [CORRECT]
D. Water's ability to dissolve nutrients
Correct Answer: C
Rationale: Water transport in plants (transpiration-cohesion-tension mechanism) relies on both cohesion between water
molecules (due to hydrogen bonding) and adhesion of water to the hydrophilic walls of xylem vessels. Together these properties
create a continuous water column that can be pulled upward.
Q4: A student adds a strong base (NaOH) to a buffer solution containing carbonic acid (H2CO3) and bicarbonate
(HCO3-). After the addition, the pH of the solution barely changes. Which of the following best explains why?
A. The strong base was too dilute to have any effect
B. The water in the solution neutralized the base before it could act
C. NaOH cannot dissolve in buffered solutions
D. The bicarbonate ion donated a proton to neutralize the added hydroxide ions [CORRECT]
Correct Answer: D
Rationale: Buffers resist pH changes by having a weak acid and its conjugate base. When a strong base (OH-) is added, the weak
acid component (H2CO3 or HCO3-) donates protons to neutralize the hydroxide, forming water and shifting the equilibrium to
WGU C190 Objective Assessment Preparation Page 1
, WGU C190 Introduction to Biology Objective Assessment 2026/2027 100 Questions | 100% Verified Answers
minimize the pH change.
Q5: Which of the following polysaccharides functions as the primary structural component of fungal cell walls and
the exoskeletons of arthropods?
A. Chitin [CORRECT]
B. Cellulose
C. Starch
D. Glycogen
Correct Answer: A
Rationale: Chitin is a structural polysaccharide made of N-acetylglucosamine monomers. It is found in the cell walls of fungi and
in the exoskeletons of insects, crustaceans, and other arthropods. Cellulose is found in plant cell walls, while starch and glycogen
are energy storage polysaccharides.
Q6: A cell biologist observes that a molecule has a hydrophilic phosphate-containing head and two hydrophobic
fatty acid tails. This molecule is a major component of cell membranes. Which type of lipid is being described?
A. Triglyceride
B. Phospholipid [CORRECT]
C. Steroid
D. Wax
Correct Answer: B
Rationale: Phospholipids consist of a glycerol backbone bonded to two fatty acid tails and a phosphate group. This amphipathic
structure, with a hydrophilic head and hydrophobic tails, makes them the fundamental building blocks of the cell membrane's
bilayer.
Q7: A biochemist treats a protein with a chemical that breaks all hydrogen bonds but leaves covalent bonds intact.
Which level(s) of protein structure would be directly affected by this treatment?
A. Primary structure only
B. Primary and secondary structure only
C. Secondary, tertiary, and quaternary structure, but not primary structure [CORRECT]
D. All four levels of protein structure
Correct Answer: C
Rationale: The primary structure is held together by peptide (covalent) bonds, so it would remain intact. Secondary structure
(alpha helices, beta sheets) depends on hydrogen bonds between the backbone. Tertiary and quaternary structures also rely
heavily on hydrogen bonds, along with other interactions. Therefore, secondary, tertiary, and quaternary structures would be
disrupted.
Q8: A molecular biologist is comparing two nucleic acid molecules. Molecule X contains the sugar deoxyribose and
the nitrogenous base thymine. Molecule Y contains the sugar ribose and the nitrogenous base uracil. Which
statement correctly identifies these molecules?
A. Molecule X is RNA and Molecule Y is DNA
B. Both molecules are types of DNA
C. Both molecules are types of RNA
D. Molecule X is DNA and Molecule Y is RNA [CORRECT]
Correct Answer: D
WGU C190 Objective Assessment Preparation Page 2
WGU C190 Introduction to
Biology
Objective Assessment
100 Questions and Answers with Rationale
Aligned with WGU C190 Course Competencies and Exam
Blueprint
Chemistry of Life, Cell Biology, Genetics, Evolution,
Ecology
Q UEST I O N S SECT I O N S F O R M AT EDIT IO N
100 7 MCQ LATEST
100% CORRECT VERIFIED ANSWERS
,WGU C190 Introduction to Biology Objective Assessment 2026/2027 100 Questions | 100% Verified Answers
Section 1: Chemistry of Life
Q1: A biologist analyzes a newly discovered mineral spring and finds that the water contains an element with 8
protons, 8 neutrons, and 10 electrons. What is the charge of this ion, and which element is it?
A. It is oxygen with a 2- charge [CORRECT]
B. It is neon with a 2- charge
C. It is oxygen with a 2+ charge
D. It is fluorine with a 1- charge
Correct Answer: A
Rationale: The number of protons (8) identifies the element as oxygen. With 10 electrons versus 8 protons, there is an excess of 2
electrons, giving the ion a net charge of 2-.
Q2: A researcher is studying how table salt (NaCl) dissolves in water. Sodium donates an electron to chlorine,
forming Na+ and Cl- ions. What type of chemical bond is formed between sodium and chlorine in the solid crystal of
NaCl?
A. Nonpolar covalent bond
B. Ionic bond [CORRECT]
C. Hydrogen bond
D. Polar covalent bond
Correct Answer: B
Rationale: An ionic bond forms when one atom transfers one or more electrons to another atom, creating oppositely charged ions
that are held together by electrostatic attraction. Sodium losing an electron to chlorine is a classic example of ionic bonding.
Q3: During a hot summer day, a plant transports water from its roots to its leaves, even though the tallest trees are
over 100 feet tall. Which property of water is most directly responsible for this ability?
A. High specific heat capacity
B. Adhesion of water to the vessel walls
C. Cohesion of water molecules and adhesion to vessel walls working together [CORRECT]
D. Water's ability to dissolve nutrients
Correct Answer: C
Rationale: Water transport in plants (transpiration-cohesion-tension mechanism) relies on both cohesion between water
molecules (due to hydrogen bonding) and adhesion of water to the hydrophilic walls of xylem vessels. Together these properties
create a continuous water column that can be pulled upward.
Q4: A student adds a strong base (NaOH) to a buffer solution containing carbonic acid (H2CO3) and bicarbonate
(HCO3-). After the addition, the pH of the solution barely changes. Which of the following best explains why?
A. The strong base was too dilute to have any effect
B. The water in the solution neutralized the base before it could act
C. NaOH cannot dissolve in buffered solutions
D. The bicarbonate ion donated a proton to neutralize the added hydroxide ions [CORRECT]
Correct Answer: D
Rationale: Buffers resist pH changes by having a weak acid and its conjugate base. When a strong base (OH-) is added, the weak
acid component (H2CO3 or HCO3-) donates protons to neutralize the hydroxide, forming water and shifting the equilibrium to
WGU C190 Objective Assessment Preparation Page 1
, WGU C190 Introduction to Biology Objective Assessment 2026/2027 100 Questions | 100% Verified Answers
minimize the pH change.
Q5: Which of the following polysaccharides functions as the primary structural component of fungal cell walls and
the exoskeletons of arthropods?
A. Chitin [CORRECT]
B. Cellulose
C. Starch
D. Glycogen
Correct Answer: A
Rationale: Chitin is a structural polysaccharide made of N-acetylglucosamine monomers. It is found in the cell walls of fungi and
in the exoskeletons of insects, crustaceans, and other arthropods. Cellulose is found in plant cell walls, while starch and glycogen
are energy storage polysaccharides.
Q6: A cell biologist observes that a molecule has a hydrophilic phosphate-containing head and two hydrophobic
fatty acid tails. This molecule is a major component of cell membranes. Which type of lipid is being described?
A. Triglyceride
B. Phospholipid [CORRECT]
C. Steroid
D. Wax
Correct Answer: B
Rationale: Phospholipids consist of a glycerol backbone bonded to two fatty acid tails and a phosphate group. This amphipathic
structure, with a hydrophilic head and hydrophobic tails, makes them the fundamental building blocks of the cell membrane's
bilayer.
Q7: A biochemist treats a protein with a chemical that breaks all hydrogen bonds but leaves covalent bonds intact.
Which level(s) of protein structure would be directly affected by this treatment?
A. Primary structure only
B. Primary and secondary structure only
C. Secondary, tertiary, and quaternary structure, but not primary structure [CORRECT]
D. All four levels of protein structure
Correct Answer: C
Rationale: The primary structure is held together by peptide (covalent) bonds, so it would remain intact. Secondary structure
(alpha helices, beta sheets) depends on hydrogen bonds between the backbone. Tertiary and quaternary structures also rely
heavily on hydrogen bonds, along with other interactions. Therefore, secondary, tertiary, and quaternary structures would be
disrupted.
Q8: A molecular biologist is comparing two nucleic acid molecules. Molecule X contains the sugar deoxyribose and
the nitrogenous base thymine. Molecule Y contains the sugar ribose and the nitrogenous base uracil. Which
statement correctly identifies these molecules?
A. Molecule X is RNA and Molecule Y is DNA
B. Both molecules are types of DNA
C. Both molecules are types of RNA
D. Molecule X is DNA and Molecule Y is RNA [CORRECT]
Correct Answer: D
WGU C190 Objective Assessment Preparation Page 2
