BIO 151 – General Biology I Practice Exam
2026/2027 – Practice Questions, Detailed Answers
& Rationales Study Guide
Section 1: The Chemistry of Life
1. Which of the following statements best describes the nature of a hydrogen
bond?
A. A strong covalent bond between a hydrogen atom and an electronegative
atom.
B. An attraction between a partially positive hydrogen atom and a partially
negative atom.
C. A bond formed by the complete transfer of an electron from hydrogen to
another atom.
D. A nonpolar interaction between two hydrogen atoms.
Correct Answer: B
Rationale: A hydrogen bond is a weak chemical attraction, not a true
bond. It forms when a hydrogen atom that is covalently bonded to a highly
electronegative atom (like oxygen or nitrogen) is attracted to another
electronegative atom nearby. Option A describes a polar covalent bond. Option C
describes an ionic bond. Option D is incorrect as hydrogen bonds are polar
interactions.
2. A solution with a pH of 4 has ______ times more H+ ions than a solution with
a pH of 7.
A. 3
B. 30
C. 100
D. 1000
Correct Answer: D
Rationale: The pH scale is logarithmic, with each unit representing a
tenfold change in H+ concentration. The difference between pH 7 and pH 4 is 3
,units. Therefore, the H+ concentration is 10^3, or 1000 times greater. Options A,
B, and C are incorrect calculations.
3. Which of the following functional groups is characterized as being polar and
hydrophilic, and is found in sugars and alcohols?
A. Carboxyl group
B. Amino group
C. Hydroxyl group
D. Sulfhydryl group
Correct Answer: C
Rationale: The hydroxyl group (-OH) is polar due to the electronegative
oxygen atom, making it hydrophilic. It is a key component of carbohydrates
(sugars) and alcohols. The carboxyl group (A) is acidic. The amino group (B) is
basic. The sulfhydryl group (D) is found in some amino acids and is relatively
nonpolar.
4. SATA: Which of the following are characteristics of living organisms? (Select
all that apply.)
A. They are composed of one or more cells.
B. They can reproduce.
C. They are made primarily of silicon-based molecules.
D. They maintain a relatively stable internal environment.
E. They do not require energy.
Correct Answers: A, B, D
Rationale: A, B, and D are all fundamental characteristics of life.
Organisms are cellular, can reproduce, and maintain homeostasis (a stable
internal environment). Option C is incorrect; life on Earth is carbon-based. Option
E is incorrect; all living things require energy to perform life's processes.
5. The partial negative charge at one end of a water molecule is attracted to the
partial positive charge of another water molecule. What is this attraction
called?
A. A covalent bond
B. A hydrogen bond
,C. An ionic bond
D. A hydrophobic interaction
Correct Answer: B
Rationale: This describes a hydrogen bond, which occurs between the
slightly positive hydrogen of one water molecule and the slightly negative oxygen
of another. Covalent bonds (A) hold the water molecule itself together. Ionic
bonds (C) involve full electron transfer. Hydrophobic interactions (D) occur
between nonpolar molecules.
6. A molecule that has both a hydrophilic region and a hydrophobic region is
best described as:
A. Amphipathic
B. Hydrophilic
C. Hydrophobic
D. A hydrocarbon
Correct Answer: A
Rationale: "Amphipathic" is the term for a molecule with both polar
(hydrophilic) and nonpolar (hydrophobic) parts. This property is crucial for the
formation of cell membranes by phospholipids. Options B and C describe
molecules with only one type of property. Option D describes a nonpolar
molecule.
7. Which level of protein structure is determined by the sequence of amino
acids?
A. Primary
B. Secondary
C. Tertiary
D. Quaternary
Correct Answer: A
Rationale: The primary structure of a protein is its unique sequence of
amino acids, which is determined by the genetic code. This sequence dictates all
higher levels of folding. Secondary structure (B) refers to alpha-helices and beta-
, sheets. Tertiary structure (C) is the overall 3D shape. Quaternary structure (D) is
the arrangement of multiple polypeptide chains.
8. The reaction that joins two monomers to form a polymer by removing a
water molecule is a:
A. Hydrolysis reaction
B. Dehydration synthesis reaction
C. Redox reaction
D. Neutralization reaction
Correct Answer: B
Rationale: Dehydration synthesis (or condensation) is the process of
joining monomers, which involves the removal of a water molecule. Hydrolysis (A)
is the opposite, breaking polymers apart by adding water. Redox (C) and
neutralization (D) are different types of chemical reactions.
9. Which of the following is NOT a polymer?
A. Starch
B. Protein
C. DNA
D. Glucose
Correct Answer: D
Rationale: Glucose is a monosaccharide, a single monomer. Starch (A),
Protein (B), and DNA (C) are all polymers made of repeating monomer units
(glucose, amino acids, and nucleotides, respectively).
10. SATA: Which of the following are functions of proteins? (Select all that
apply.)
A. Catalyzing metabolic reactions.
B. Storing genetic information.
C. Transporting substances across membranes.
D. Providing structural support.
E. Serving as a primary source of long-term energy storage.
Correct Answers: A, C, D
2026/2027 – Practice Questions, Detailed Answers
& Rationales Study Guide
Section 1: The Chemistry of Life
1. Which of the following statements best describes the nature of a hydrogen
bond?
A. A strong covalent bond between a hydrogen atom and an electronegative
atom.
B. An attraction between a partially positive hydrogen atom and a partially
negative atom.
C. A bond formed by the complete transfer of an electron from hydrogen to
another atom.
D. A nonpolar interaction between two hydrogen atoms.
Correct Answer: B
Rationale: A hydrogen bond is a weak chemical attraction, not a true
bond. It forms when a hydrogen atom that is covalently bonded to a highly
electronegative atom (like oxygen or nitrogen) is attracted to another
electronegative atom nearby. Option A describes a polar covalent bond. Option C
describes an ionic bond. Option D is incorrect as hydrogen bonds are polar
interactions.
2. A solution with a pH of 4 has ______ times more H+ ions than a solution with
a pH of 7.
A. 3
B. 30
C. 100
D. 1000
Correct Answer: D
Rationale: The pH scale is logarithmic, with each unit representing a
tenfold change in H+ concentration. The difference between pH 7 and pH 4 is 3
,units. Therefore, the H+ concentration is 10^3, or 1000 times greater. Options A,
B, and C are incorrect calculations.
3. Which of the following functional groups is characterized as being polar and
hydrophilic, and is found in sugars and alcohols?
A. Carboxyl group
B. Amino group
C. Hydroxyl group
D. Sulfhydryl group
Correct Answer: C
Rationale: The hydroxyl group (-OH) is polar due to the electronegative
oxygen atom, making it hydrophilic. It is a key component of carbohydrates
(sugars) and alcohols. The carboxyl group (A) is acidic. The amino group (B) is
basic. The sulfhydryl group (D) is found in some amino acids and is relatively
nonpolar.
4. SATA: Which of the following are characteristics of living organisms? (Select
all that apply.)
A. They are composed of one or more cells.
B. They can reproduce.
C. They are made primarily of silicon-based molecules.
D. They maintain a relatively stable internal environment.
E. They do not require energy.
Correct Answers: A, B, D
Rationale: A, B, and D are all fundamental characteristics of life.
Organisms are cellular, can reproduce, and maintain homeostasis (a stable
internal environment). Option C is incorrect; life on Earth is carbon-based. Option
E is incorrect; all living things require energy to perform life's processes.
5. The partial negative charge at one end of a water molecule is attracted to the
partial positive charge of another water molecule. What is this attraction
called?
A. A covalent bond
B. A hydrogen bond
,C. An ionic bond
D. A hydrophobic interaction
Correct Answer: B
Rationale: This describes a hydrogen bond, which occurs between the
slightly positive hydrogen of one water molecule and the slightly negative oxygen
of another. Covalent bonds (A) hold the water molecule itself together. Ionic
bonds (C) involve full electron transfer. Hydrophobic interactions (D) occur
between nonpolar molecules.
6. A molecule that has both a hydrophilic region and a hydrophobic region is
best described as:
A. Amphipathic
B. Hydrophilic
C. Hydrophobic
D. A hydrocarbon
Correct Answer: A
Rationale: "Amphipathic" is the term for a molecule with both polar
(hydrophilic) and nonpolar (hydrophobic) parts. This property is crucial for the
formation of cell membranes by phospholipids. Options B and C describe
molecules with only one type of property. Option D describes a nonpolar
molecule.
7. Which level of protein structure is determined by the sequence of amino
acids?
A. Primary
B. Secondary
C. Tertiary
D. Quaternary
Correct Answer: A
Rationale: The primary structure of a protein is its unique sequence of
amino acids, which is determined by the genetic code. This sequence dictates all
higher levels of folding. Secondary structure (B) refers to alpha-helices and beta-
, sheets. Tertiary structure (C) is the overall 3D shape. Quaternary structure (D) is
the arrangement of multiple polypeptide chains.
8. The reaction that joins two monomers to form a polymer by removing a
water molecule is a:
A. Hydrolysis reaction
B. Dehydration synthesis reaction
C. Redox reaction
D. Neutralization reaction
Correct Answer: B
Rationale: Dehydration synthesis (or condensation) is the process of
joining monomers, which involves the removal of a water molecule. Hydrolysis (A)
is the opposite, breaking polymers apart by adding water. Redox (C) and
neutralization (D) are different types of chemical reactions.
9. Which of the following is NOT a polymer?
A. Starch
B. Protein
C. DNA
D. Glucose
Correct Answer: D
Rationale: Glucose is a monosaccharide, a single monomer. Starch (A),
Protein (B), and DNA (C) are all polymers made of repeating monomer units
(glucose, amino acids, and nucleotides, respectively).
10. SATA: Which of the following are functions of proteins? (Select all that
apply.)
A. Catalyzing metabolic reactions.
B. Storing genetic information.
C. Transporting substances across membranes.
D. Providing structural support.
E. Serving as a primary source of long-term energy storage.
Correct Answers: A, C, D
