BIOL251 MODULE 2 EXAM REVIEW -
HUMAN ANATOMY & PHYSIOLOGY| 50
QUESTIONS | PORTAGE LEARNING
1. Which of the following best describes the difference between an ionic bond and a polar
covalent bond?
A. Ionic bonds result from the electrostatic attraction between oppositely charged ions,
while polar covalent bonds involve unequal sharing of electrons.
B. Ionic bonds involve the equal sharing of electrons, whereas polar covalent bonds involve
total transfer.
C. Ionic bonds are weaker than hydrogen bonds, whereas polar covalent bonds are the
strongest known bonds.
D. Polar covalent bonds only occur between identical atoms, whereas ionic bonds occur
between different atoms.
Answer: A
Conceptual Explanation: Ionic bonds are formed by the transfer of electrons resulting in
attraction between cations and anions. Polar covalent bonds involve electrons being
shared, but pulled closer to the more electronegative atom.
,2. In a bicarbonate buffer system, what happens when excess hydrogen ions (H+) are added
to the blood?
A. The pH increases drastically as hydroxide ions are released.
B. H+ reacts with bicarbonate ions (HCO3-) to form carbonic acid (H2CO3), minimizing pH
change.
C. Bicarbonate ions dissociate into carbon dioxide and water to absorb the heat.
D. The concentration of H+ increases linearly without any chemical intervention.
Answer: B
Conceptual Explanation: Buffers resist pH changes; in this system, the bicarbonate ion
acts as a weak base to pick up excess protons, forming carbonic acid.
3. Which property of water allows it to absorb significant heat without a large change in its
own temperature?
A. High density as a solid
B. Low surface tension
C. High heat capacity
D. Non-polar covalent nature
Answer: C
, Conceptual Explanation: Water’s high heat capacity is due to hydrogen bonding, which
requires significant energy to break before the molecules can move faster and raise the
temperature.
4. What is the primary function of a kinase enzyme in cellular signaling?
A. To degrade protein chains into individual amino acids.
B. To catalyze the hydrolysis of ATP into ADP and Pi for muscle contraction only.
C. To facilitate the synthesis of phospholipids in the smooth ER.
D. To add a phosphate group to a protein, often changing its activity.
Answer: D
Conceptual Explanation: Kinases are enzymes that catalyze phosphorylation, a key
mechanism for regulating protein function in signal transduction pathways.
5. Which of the following best describes the ‘Fluid Mosaic Model’ of the plasma membrane?
A. A rigid wall of proteins surrounded by a thin layer of water.
B. A double layer of phospholipids with embedded proteins that can move laterally.
C. A single layer of cholesterol molecules that prevents any molecular transport.
D. A solid lattice of carbohydrates that provides structural support to the cytoplasm.
Answer: B
Conceptual Explanation: The fluid mosaic model describes the membrane as a dynamic
phospholipid bilayer where proteins and cholesterol can move freely within the layer.
HUMAN ANATOMY & PHYSIOLOGY| 50
QUESTIONS | PORTAGE LEARNING
1. Which of the following best describes the difference between an ionic bond and a polar
covalent bond?
A. Ionic bonds result from the electrostatic attraction between oppositely charged ions,
while polar covalent bonds involve unequal sharing of electrons.
B. Ionic bonds involve the equal sharing of electrons, whereas polar covalent bonds involve
total transfer.
C. Ionic bonds are weaker than hydrogen bonds, whereas polar covalent bonds are the
strongest known bonds.
D. Polar covalent bonds only occur between identical atoms, whereas ionic bonds occur
between different atoms.
Answer: A
Conceptual Explanation: Ionic bonds are formed by the transfer of electrons resulting in
attraction between cations and anions. Polar covalent bonds involve electrons being
shared, but pulled closer to the more electronegative atom.
,2. In a bicarbonate buffer system, what happens when excess hydrogen ions (H+) are added
to the blood?
A. The pH increases drastically as hydroxide ions are released.
B. H+ reacts with bicarbonate ions (HCO3-) to form carbonic acid (H2CO3), minimizing pH
change.
C. Bicarbonate ions dissociate into carbon dioxide and water to absorb the heat.
D. The concentration of H+ increases linearly without any chemical intervention.
Answer: B
Conceptual Explanation: Buffers resist pH changes; in this system, the bicarbonate ion
acts as a weak base to pick up excess protons, forming carbonic acid.
3. Which property of water allows it to absorb significant heat without a large change in its
own temperature?
A. High density as a solid
B. Low surface tension
C. High heat capacity
D. Non-polar covalent nature
Answer: C
, Conceptual Explanation: Water’s high heat capacity is due to hydrogen bonding, which
requires significant energy to break before the molecules can move faster and raise the
temperature.
4. What is the primary function of a kinase enzyme in cellular signaling?
A. To degrade protein chains into individual amino acids.
B. To catalyze the hydrolysis of ATP into ADP and Pi for muscle contraction only.
C. To facilitate the synthesis of phospholipids in the smooth ER.
D. To add a phosphate group to a protein, often changing its activity.
Answer: D
Conceptual Explanation: Kinases are enzymes that catalyze phosphorylation, a key
mechanism for regulating protein function in signal transduction pathways.
5. Which of the following best describes the ‘Fluid Mosaic Model’ of the plasma membrane?
A. A rigid wall of proteins surrounded by a thin layer of water.
B. A double layer of phospholipids with embedded proteins that can move laterally.
C. A single layer of cholesterol molecules that prevents any molecular transport.
D. A solid lattice of carbohydrates that provides structural support to the cytoplasm.
Answer: B
Conceptual Explanation: The fluid mosaic model describes the membrane as a dynamic
phospholipid bilayer where proteins and cholesterol can move freely within the layer.
