BIOL251 Human Anatomy & Physiology I
w/Lab 2026 | Module 2 Exam Review |70+
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BIOL251 Human Anatomy & Physiology I with Lab — 2026 Module 2 Exam
Review
70+ Practice Questions with Correct Answers and Detailed Explanations |
LockDown Browser | Portage Learning
SECTION I: Chemistry of Life (Questions 1–15)
1. Which of the following is the primary energy currency of the cell?
A) ATP
B) DNA
C) RNA
D) NADH
Correct Answer: A) ATP
Explanation: Adenosine triphosphate (ATP) is the primary energy currency of the
cell. It stores energy in the bonds between its phosphate groups. When ATP is
hydrolyzed to ADP and inorganic phosphate, energy is released to drive cellular
processes. DNA (B) and RNA (C) are genetic molecules. NADH (D) is an electron
carrier involved in cellular respiration.
,2. Rotation about a single bond in a fatty acid chain affects:
A) The degree of saturation
B) The membrane fluidity by introducing kinks
C) The number of double bonds
D) The length of the chain
Correct Answer: B) The membrane fluidity by introducing kinks
Explanation: Rotation about a single bond in the hydrocarbon tail of a fatty acid
allows the chain to bend and flex. When double bonds are present (unsaturated
fatty acids), rotation about single bonds adjacent to the double bond introduces
kinks in the chain, preventing tight packing and increasing membrane fluidity. The
degree of saturation (A) and number of double bonds (C) are determined by the
presence of double bonds, not rotation. Chain length (D) is determined by the
number of carbon atoms.
3. The pH scale measures:
A) The concentration of hydrogen ions
B) The concentration of oxygen
C) The concentration of sodium
D) The concentration of chloride
Correct Answer: A) The concentration of hydrogen ions
Explanation: The pH scale measures the concentration of hydrogen ions (H⁺) in a
solution. It is calculated as the negative logarithm of the H⁺ concentration: pH = -
log[H⁺]. A pH of 7 is neutral, below 7 is acidic, and above 7 is basic (alkaline). The
other options (B, C, D) refer to other ions that are not directly measured by pH.
4. Which type of bond involves the sharing of electron pairs?
A) Ionic bond
B) Covalent bond
, C) Hydrogen bond
D) Van der Waals
Correct Answer: B) Covalent bond
Explanation: A covalent bond is formed when two atoms share one or more pairs
of electrons. This is the strongest type of chemical bond. Ionic bonds (A) involve
the transfer of electrons from one atom to another. Hydrogen bonds (C) are weak
attractions between a hydrogen atom and an electronegative atom. Van der Waals
interactions (D) are weak, temporary attractions between molecules.
5. Rotation about a single bond in a protein backbone contributes to:
A) Primary structure
B) Secondary structure flexibility
C) Tertiary structure only
D) Quaternary structure only
Correct Answer: B) Secondary structure flexibility
Explanation: Rotation about a single bond in the protein backbone occurs around
the phi (φ) and psi (ψ) bonds adjacent to the peptide bond. This rotation allows
the polypeptide chain to adopt different secondary structures such as alpha
helices and beta sheets. Primary structure (A) is the sequence of amino acids
determined by covalent peptide bonds. Tertiary (C) and quaternary (D) structures
are stabilized by various interactions, but the flexibility from bond rotation is
fundamental to secondary structure formation.
6. Which macromolecule is composed of amino acids?
A) Carbohydrates
B) Lipids
C) Proteins
D) Nucleic acids
Correct Answer: C) Proteins
w/Lab 2026 | Module 2 Exam Review |70+
Questions and Answers Summary |LockDown
Browser |Portage Learning
BIOL251 Human Anatomy & Physiology I with Lab — 2026 Module 2 Exam
Review
70+ Practice Questions with Correct Answers and Detailed Explanations |
LockDown Browser | Portage Learning
SECTION I: Chemistry of Life (Questions 1–15)
1. Which of the following is the primary energy currency of the cell?
A) ATP
B) DNA
C) RNA
D) NADH
Correct Answer: A) ATP
Explanation: Adenosine triphosphate (ATP) is the primary energy currency of the
cell. It stores energy in the bonds between its phosphate groups. When ATP is
hydrolyzed to ADP and inorganic phosphate, energy is released to drive cellular
processes. DNA (B) and RNA (C) are genetic molecules. NADH (D) is an electron
carrier involved in cellular respiration.
,2. Rotation about a single bond in a fatty acid chain affects:
A) The degree of saturation
B) The membrane fluidity by introducing kinks
C) The number of double bonds
D) The length of the chain
Correct Answer: B) The membrane fluidity by introducing kinks
Explanation: Rotation about a single bond in the hydrocarbon tail of a fatty acid
allows the chain to bend and flex. When double bonds are present (unsaturated
fatty acids), rotation about single bonds adjacent to the double bond introduces
kinks in the chain, preventing tight packing and increasing membrane fluidity. The
degree of saturation (A) and number of double bonds (C) are determined by the
presence of double bonds, not rotation. Chain length (D) is determined by the
number of carbon atoms.
3. The pH scale measures:
A) The concentration of hydrogen ions
B) The concentration of oxygen
C) The concentration of sodium
D) The concentration of chloride
Correct Answer: A) The concentration of hydrogen ions
Explanation: The pH scale measures the concentration of hydrogen ions (H⁺) in a
solution. It is calculated as the negative logarithm of the H⁺ concentration: pH = -
log[H⁺]. A pH of 7 is neutral, below 7 is acidic, and above 7 is basic (alkaline). The
other options (B, C, D) refer to other ions that are not directly measured by pH.
4. Which type of bond involves the sharing of electron pairs?
A) Ionic bond
B) Covalent bond
, C) Hydrogen bond
D) Van der Waals
Correct Answer: B) Covalent bond
Explanation: A covalent bond is formed when two atoms share one or more pairs
of electrons. This is the strongest type of chemical bond. Ionic bonds (A) involve
the transfer of electrons from one atom to another. Hydrogen bonds (C) are weak
attractions between a hydrogen atom and an electronegative atom. Van der Waals
interactions (D) are weak, temporary attractions between molecules.
5. Rotation about a single bond in a protein backbone contributes to:
A) Primary structure
B) Secondary structure flexibility
C) Tertiary structure only
D) Quaternary structure only
Correct Answer: B) Secondary structure flexibility
Explanation: Rotation about a single bond in the protein backbone occurs around
the phi (φ) and psi (ψ) bonds adjacent to the peptide bond. This rotation allows
the polypeptide chain to adopt different secondary structures such as alpha
helices and beta sheets. Primary structure (A) is the sequence of amino acids
determined by covalent peptide bonds. Tertiary (C) and quaternary (D) structures
are stabilized by various interactions, but the flexibility from bond rotation is
fundamental to secondary structure formation.
6. Which macromolecule is composed of amino acids?
A) Carbohydrates
B) Lipids
C) Proteins
D) Nucleic acids
Correct Answer: C) Proteins
