BIOL 271 / BIOL271 Module 2: Practice Exam Actual
2026/2027 with Detailed Rationales | 100% Verified |
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SECTION 1: Core Biological Principles
(Questions 1–10)
Q1: Which property of water is most directly responsible for its ability to dissolve
ionic compounds such as sodium chloride?
A. Its low specific heat capacity
B. Its ability to form hydrogen bonds with nonpolar molecules
C. Its polarity and capacity to surround and shield ions [CORRECT]
D. Its high density as a solid compared to its liquid form
Correct Answer: C
Rationale: Correct because water's polar nature allows it to form hydration shells
around ions, effectively shielding their charges and dissolving ionic compounds.
Q2: A solution with a pH of 3 contains how many times more hydrogen ions than a
solution with a pH of 5?
A. 2 times more
B. 10 times more
C. 100 times more [CORRECT]
D. 1,000 times more
Correct Answer: C
Rationale: Correct because the pH scale is logarithmic; each whole number
difference represents a tenfold change in hydrogen ion concentration, so pH 3 has
10² = 100 times more H⁺ than pH 5.
Q3: Which functional group is present in all amino acids and gives them their acidic
properties?
A. The amino group (-NH₂)
B. The carboxyl group (-COOH) [CORRECT]
, C. The hydroxyl group (-OH)
D. The methyl group (-CH₃)
Correct Answer: B
Rationale: Correct because the carboxyl group is the acidic functional group present
in all amino acids that can donate a proton in aqueous solution.
Q4: Which class of macromolecules includes cholesterol, testosterone, and
estrogen?
A. Proteins
B. Carbohydrates
C. Lipids [CORRECT]
D. Nucleic acids
Correct Answer: C
Rationale: Correct because cholesterol and steroid hormones like testosterone and
estrogen are classified as lipids, specifically steroids derived from a four-ring carbon
skeleton.
Q5: In a dehydration synthesis reaction, which type of bond is formed between
monomers?
A. Hydrogen bonds
B. Ionic bonds
C. Covalent bonds [CORRECT]
D. Van der Waals interactions
Correct Answer: C
Rationale: Correct because dehydration synthesis removes a water molecule and
forms a covalent bond linking monomers together, such as peptide bonds in proteins
or glycosidic linkages in carbohydrates.
Q6: Which level of protein structure describes the overall three-dimensional shape
formed by interactions among R-groups?
A. Primary structure
B. Secondary structure
C. Tertiary structure [CORRECT]
D. Quaternary structure
Correct Answer: C
Rationale: Correct because tertiary structure is the overall three-dimensional
conformation of a polypeptide resulting from interactions among amino acid
2026/2027 with Detailed Rationales | 100% Verified |
Pass Guaranteed – A+ Graded
SECTION 1: Core Biological Principles
(Questions 1–10)
Q1: Which property of water is most directly responsible for its ability to dissolve
ionic compounds such as sodium chloride?
A. Its low specific heat capacity
B. Its ability to form hydrogen bonds with nonpolar molecules
C. Its polarity and capacity to surround and shield ions [CORRECT]
D. Its high density as a solid compared to its liquid form
Correct Answer: C
Rationale: Correct because water's polar nature allows it to form hydration shells
around ions, effectively shielding their charges and dissolving ionic compounds.
Q2: A solution with a pH of 3 contains how many times more hydrogen ions than a
solution with a pH of 5?
A. 2 times more
B. 10 times more
C. 100 times more [CORRECT]
D. 1,000 times more
Correct Answer: C
Rationale: Correct because the pH scale is logarithmic; each whole number
difference represents a tenfold change in hydrogen ion concentration, so pH 3 has
10² = 100 times more H⁺ than pH 5.
Q3: Which functional group is present in all amino acids and gives them their acidic
properties?
A. The amino group (-NH₂)
B. The carboxyl group (-COOH) [CORRECT]
, C. The hydroxyl group (-OH)
D. The methyl group (-CH₃)
Correct Answer: B
Rationale: Correct because the carboxyl group is the acidic functional group present
in all amino acids that can donate a proton in aqueous solution.
Q4: Which class of macromolecules includes cholesterol, testosterone, and
estrogen?
A. Proteins
B. Carbohydrates
C. Lipids [CORRECT]
D. Nucleic acids
Correct Answer: C
Rationale: Correct because cholesterol and steroid hormones like testosterone and
estrogen are classified as lipids, specifically steroids derived from a four-ring carbon
skeleton.
Q5: In a dehydration synthesis reaction, which type of bond is formed between
monomers?
A. Hydrogen bonds
B. Ionic bonds
C. Covalent bonds [CORRECT]
D. Van der Waals interactions
Correct Answer: C
Rationale: Correct because dehydration synthesis removes a water molecule and
forms a covalent bond linking monomers together, such as peptide bonds in proteins
or glycosidic linkages in carbohydrates.
Q6: Which level of protein structure describes the overall three-dimensional shape
formed by interactions among R-groups?
A. Primary structure
B. Secondary structure
C. Tertiary structure [CORRECT]
D. Quaternary structure
Correct Answer: C
Rationale: Correct because tertiary structure is the overall three-dimensional
conformation of a polypeptide resulting from interactions among amino acid
