WGU C190 INTRO TO BIOLOGY OA EXAM 2026 |
COMPLETE VERIFIED QUESTIONS & ANSWERS
| GUARANTEED PASS A+
WGU C190 — INTRO TO BIOLOGY OA EXAM
COMPLETE VERIFIED QUESTIONS & ANSWERS | GUARANTEED PASS A+
DOCUMENT OVERVIEW
This exam preparation guide covers all major topics tested in the WGU C190
Introduction to Biology OA (Objective Assessment). It is organized into key biological
domains including: Chemistry of Life, Cell Structure & Function, Membrane
Transport, Metabolism & Energy, Photosynthesis, Cellular Respiration, DNA &
RNA, Protein Synthesis, Cell Division, Genetics & Heredity, Evolution & Natural
Selection, Biological Classification, Ecology, and Human Body Systems. Each
question includes five answer choices (A–E), the CORRECT ANSWER clearly marked,
and a RATIONALE explaining why that answer is correct. Use this guide to reinforce
understanding, identify weak areas, and build confidence before your OA. All 300
questions are aligned with WGU C190 competencies.
SECTION 1: CHEMISTRY OF LIFE
Q1. What is the atomic number of an element?
A. The total number of protons and neutrons in the nucleus
B. The mass of the atom measured in daltons
C. The number of electrons in the outermost shell
D. The number of neutrons in the nucleus
E. The number of protons in the nucleus
CORRECT ANSWER: E. The number of protons in the nucleus
RATIONALE: The atomic number uniquely identifies an element and equals the
number of protons in its nucleus. It also equals the number of electrons in a neutral
atom.
,Q2. Which type of bond involves the sharing of electrons between atoms?
A. Ionic bond
B. Hydrogen bond
C. Covalent bond
D. Van der Waals interaction
E. Polar bond
CORRECT ANSWER: C. Covalent bond
RATIONALE: Covalent bonds form when two atoms share one or more pairs of
electrons. This is the strongest type of chemical bond found in biological molecules.
Q3. Water is considered a polar molecule because:
A. It contains only hydrogen atoms
B. It has an equal distribution of electrons
C. Oxygen attracts electrons more strongly than hydrogen, creating partial charges
D. It forms ionic bonds with other water molecules
E. It is a gas at room temperature
CORRECT ANSWER: C. Oxygen attracts electrons more strongly than
hydrogen, creating partial charges
RATIONALE: Oxygen is more electronegative than hydrogen. This unequal
sharing of electrons gives the oxygen end a partial negative charge and the hydrogen
ends partial positive charges, making water polar.
Q4. Which property of water allows it to stick to other water molecules?
A. Adhesion
B. Surface tension only
C. Cohesion
D. Capillary action
E. Hydrophobicity
, CORRECT ANSWER: C. Cohesion
RATIONALE: Cohesion is the attraction of water molecules to each other via
hydrogen bonds. This property is responsible for surface tension and helps water move
through plant xylem.
Q5. A solution with a pH of 3 is best described as:
A. Strongly basic
B. Neutral
C. Weakly basic
D. Weakly acidic
E. Strongly acidic
CORRECT ANSWER: E. Strongly acidic
RATIONALE: The pH scale runs from 0 to 14. A pH of 3 is well below 7 (neutral),
indicating a high concentration of hydrogen ions and a strongly acidic solution.
Q6. Which macromolecule serves as the primary source of quick energy for
cells?
A. Lipids
B. Proteins
C. Nucleic acids
D. Carbohydrates
E. Steroids
CORRECT ANSWER: D. Carbohydrates
RATIONALE: Carbohydrates, particularly glucose, are the body's preferred and
most rapidly available energy source. They are broken down during cellular respiration
to produce ATP.
Q7. What is the monomer of proteins?
, A. Glucose
B. Fatty acids
C. Nucleotides
D. Amino acids
E. Glycerol
CORRECT ANSWER: D. Amino acids
RATIONALE: Proteins are polymers made of amino acid monomers linked by
peptide bonds. There are 20 different amino acids that combine in different sequences
to form all proteins.
Q8. Which type of lipid makes up the cell membrane?
A. Triglycerides
B. Steroids
C. Waxes
D. Phospholipids
E. Saturated fats
CORRECT ANSWER: D. Phospholipids
RATIONALE: Phospholipids have a hydrophilic (water-loving) head and two
hydrophobic (water-fearing) fatty acid tails. This structure causes them to spontaneously
form a bilayer in aqueous environments, forming the cell membrane.
Q9. The process of breaking down polymers into monomers using water is called:
A. Dehydration synthesis
B. Polymerization
C. Hydrolysis
D. Condensation
E. Oxidation
CORRECT ANSWER: C. Hydrolysis
COMPLETE VERIFIED QUESTIONS & ANSWERS
| GUARANTEED PASS A+
WGU C190 — INTRO TO BIOLOGY OA EXAM
COMPLETE VERIFIED QUESTIONS & ANSWERS | GUARANTEED PASS A+
DOCUMENT OVERVIEW
This exam preparation guide covers all major topics tested in the WGU C190
Introduction to Biology OA (Objective Assessment). It is organized into key biological
domains including: Chemistry of Life, Cell Structure & Function, Membrane
Transport, Metabolism & Energy, Photosynthesis, Cellular Respiration, DNA &
RNA, Protein Synthesis, Cell Division, Genetics & Heredity, Evolution & Natural
Selection, Biological Classification, Ecology, and Human Body Systems. Each
question includes five answer choices (A–E), the CORRECT ANSWER clearly marked,
and a RATIONALE explaining why that answer is correct. Use this guide to reinforce
understanding, identify weak areas, and build confidence before your OA. All 300
questions are aligned with WGU C190 competencies.
SECTION 1: CHEMISTRY OF LIFE
Q1. What is the atomic number of an element?
A. The total number of protons and neutrons in the nucleus
B. The mass of the atom measured in daltons
C. The number of electrons in the outermost shell
D. The number of neutrons in the nucleus
E. The number of protons in the nucleus
CORRECT ANSWER: E. The number of protons in the nucleus
RATIONALE: The atomic number uniquely identifies an element and equals the
number of protons in its nucleus. It also equals the number of electrons in a neutral
atom.
,Q2. Which type of bond involves the sharing of electrons between atoms?
A. Ionic bond
B. Hydrogen bond
C. Covalent bond
D. Van der Waals interaction
E. Polar bond
CORRECT ANSWER: C. Covalent bond
RATIONALE: Covalent bonds form when two atoms share one or more pairs of
electrons. This is the strongest type of chemical bond found in biological molecules.
Q3. Water is considered a polar molecule because:
A. It contains only hydrogen atoms
B. It has an equal distribution of electrons
C. Oxygen attracts electrons more strongly than hydrogen, creating partial charges
D. It forms ionic bonds with other water molecules
E. It is a gas at room temperature
CORRECT ANSWER: C. Oxygen attracts electrons more strongly than
hydrogen, creating partial charges
RATIONALE: Oxygen is more electronegative than hydrogen. This unequal
sharing of electrons gives the oxygen end a partial negative charge and the hydrogen
ends partial positive charges, making water polar.
Q4. Which property of water allows it to stick to other water molecules?
A. Adhesion
B. Surface tension only
C. Cohesion
D. Capillary action
E. Hydrophobicity
, CORRECT ANSWER: C. Cohesion
RATIONALE: Cohesion is the attraction of water molecules to each other via
hydrogen bonds. This property is responsible for surface tension and helps water move
through plant xylem.
Q5. A solution with a pH of 3 is best described as:
A. Strongly basic
B. Neutral
C. Weakly basic
D. Weakly acidic
E. Strongly acidic
CORRECT ANSWER: E. Strongly acidic
RATIONALE: The pH scale runs from 0 to 14. A pH of 3 is well below 7 (neutral),
indicating a high concentration of hydrogen ions and a strongly acidic solution.
Q6. Which macromolecule serves as the primary source of quick energy for
cells?
A. Lipids
B. Proteins
C. Nucleic acids
D. Carbohydrates
E. Steroids
CORRECT ANSWER: D. Carbohydrates
RATIONALE: Carbohydrates, particularly glucose, are the body's preferred and
most rapidly available energy source. They are broken down during cellular respiration
to produce ATP.
Q7. What is the monomer of proteins?
, A. Glucose
B. Fatty acids
C. Nucleotides
D. Amino acids
E. Glycerol
CORRECT ANSWER: D. Amino acids
RATIONALE: Proteins are polymers made of amino acid monomers linked by
peptide bonds. There are 20 different amino acids that combine in different sequences
to form all proteins.
Q8. Which type of lipid makes up the cell membrane?
A. Triglycerides
B. Steroids
C. Waxes
D. Phospholipids
E. Saturated fats
CORRECT ANSWER: D. Phospholipids
RATIONALE: Phospholipids have a hydrophilic (water-loving) head and two
hydrophobic (water-fearing) fatty acid tails. This structure causes them to spontaneously
form a bilayer in aqueous environments, forming the cell membrane.
Q9. The process of breaking down polymers into monomers using water is called:
A. Dehydration synthesis
B. Polymerization
C. Hydrolysis
D. Condensation
E. Oxidation
CORRECT ANSWER: C. Hydrolysis
