WGU C190 INTRODUCTION TO
BIOLOGY PRACTICE EXAM
QUESTIONS AND ANSWERS
1. Which component of the scientific method involves a tentative, testable explanation for an
observed phenomenon?
A. Conclusion
B. Hypothesis
C. Theory
D. Experiment
Answer: B
Conceptual Explanation: A hypothesis is a preliminary, testable explanation based on
observations. A theory is a broader, well-substantiated explanation.
2. Water’s ability to stick to other surfaces, such as the walls of a plant’s xylem, is known as:
A. Surface tension
B. Cohesion
C. Adhesion
,D. Specific heat
Answer: C
Conceptual Explanation: Adhesion is the attraction between water molecules and
different substances. Cohesion is the attraction between water molecules themselves.
3. Which of the following macromolecules is primarily responsible for long-term energy
storage and insulating organs?
A. Proteins
B. Lipids
C. Nucleic acids
D. Carbohydrates
Answer: B
Conceptual Explanation: Lipids, specifically fats (triglycerides), are used for long-term
energy storage, insulation, and protection.
4. The primary structure of a protein is determined by the sequence of:
A. Amino acids
B. Nucleotides
C. Fatty acids
D. Monosaccharides
, Answer: A
Conceptual Explanation: Proteins are polymers composed of amino acid monomers
linked by peptide bonds.
5. Which organelle is known as the ‘powerhouse’ of the cell because it generates ATP through
aerobic respiration?
A. Ribosome
B. Mitochondrion
C. Golgi apparatus
D. Lysosome
Answer: B
Conceptual Explanation: Mitochondria are the sites of cellular respiration, converting
chemical energy from food into ATP.
6. In the cell membrane, the phospholipid tails are __________, meaning they repel water.
A. Hydrophilic
B. Ionic
C. Amphipathic
D. Hydrophobic
Answer: D
BIOLOGY PRACTICE EXAM
QUESTIONS AND ANSWERS
1. Which component of the scientific method involves a tentative, testable explanation for an
observed phenomenon?
A. Conclusion
B. Hypothesis
C. Theory
D. Experiment
Answer: B
Conceptual Explanation: A hypothesis is a preliminary, testable explanation based on
observations. A theory is a broader, well-substantiated explanation.
2. Water’s ability to stick to other surfaces, such as the walls of a plant’s xylem, is known as:
A. Surface tension
B. Cohesion
C. Adhesion
,D. Specific heat
Answer: C
Conceptual Explanation: Adhesion is the attraction between water molecules and
different substances. Cohesion is the attraction between water molecules themselves.
3. Which of the following macromolecules is primarily responsible for long-term energy
storage and insulating organs?
A. Proteins
B. Lipids
C. Nucleic acids
D. Carbohydrates
Answer: B
Conceptual Explanation: Lipids, specifically fats (triglycerides), are used for long-term
energy storage, insulation, and protection.
4. The primary structure of a protein is determined by the sequence of:
A. Amino acids
B. Nucleotides
C. Fatty acids
D. Monosaccharides
, Answer: A
Conceptual Explanation: Proteins are polymers composed of amino acid monomers
linked by peptide bonds.
5. Which organelle is known as the ‘powerhouse’ of the cell because it generates ATP through
aerobic respiration?
A. Ribosome
B. Mitochondrion
C. Golgi apparatus
D. Lysosome
Answer: B
Conceptual Explanation: Mitochondria are the sites of cellular respiration, converting
chemical energy from food into ATP.
6. In the cell membrane, the phospholipid tails are __________, meaning they repel water.
A. Hydrophilic
B. Ionic
C. Amphipathic
D. Hydrophobic
Answer: D
