,BIOL 251 Module 2 | Human Anatomy & Physiology I w/Lab
Exam Q&A | Portage Learning
1. Which statement accurately describes the function of the plasma membrane?
A) It synthesizes proteins for cellular export
B) It acts as a selectively permeable barrier controlling material movement
C) It generates ATP through oxidative phosphorylation
D) It stores genetic information for cell division
Correct Answer: It acts as a selectively permeable barrier controlling material
movement
Rationale: The plasma membrane is a phospholipid bilayer with embedded proteins
that regulates the entry and exit of substances, maintaining the internal environment
of the cell. Protein synthesis occurs at ribosomes, ATP generation happens in
mitochondria, and genetic storage is the nucleus's role.
2. In the context of cellular transport, what is the primary mechanism by which
oxygen and carbon dioxide move between cells and capillaries?
A) Facilitated diffusion
B) Simple diffusion
C) Active transport
D) Vesicular transport
Correct Answer: Simple diffusion
Rationale: Small, nonpolar gases like oxygen and carbon dioxide diffuse passively
down their concentration gradients directly through the phospholipid bilayer. This
,process requires no energy or carrier proteins, distinguishing it from facilitated
diffusion and active transport.
3. A researcher observes a cell that possesses a distinct nucleus and several
membrane-bound organelles. Based on these characteristics, how should this cell be
classified?
A) Prokaryotic
B) Eukaryotic
C) Bacterial
D) Viral
Correct Answer: Eukaryotic
Rationale: Eukaryotic cells are defined by a true nucleus enclosed within a
membrane and the presence of membrane-bound organelles such as mitochondria
and the endoplasmic reticulum. Prokaryotic cells, like bacteria, lack a nucleus and
these organelles.
4. What is the primary role of the sodium-potassium pump in maintaining cellular
homeostasis?
A) Moving sodium and potassium down their concentration gradients
B) Exporting three sodium ions and importing two potassium ions using ATP
C) Transporting glucose into the cell along with sodium
D) Regulating intracellular calcium concentration
Correct Answer: Exporting three sodium ions and importing two potassium ions
using ATP
, Rationale: The sodium-potassium pump (Na+/K+-ATPase) uses ATP to actively
transport three sodium ions out of the cell and two potassium ions into the cell
against their concentration gradients. This maintains the resting membrane potential
and cell volume.
5. A white blood cell engulfs a bacterium by forming a vesicle around it. What is this
process called?
A) Pinocytosis
B) Phagocytosis
C) Exocytosis
D) Receptor-mediated endocytosis
Correct Answer: Phagocytosis
Rationale: Phagocytosis is a form of endocytosis where the cell engulfs large
particles such as bacteria or dead cells. Pinocytosis involves the ingestion of fluids
and solutes, while exocytosis is the release of materials from the cell.
6. During which phase of the cell cycle does DNA replication occur?
A) G1 phase
B) S phase
C) G2 phase
D) M phase
Correct Answer: S phase
Rationale: The S phase (synthesis phase) is when DNA replication takes place,
ensuring that each daughter cell receives a complete set of chromosomes. The G1
Exam Q&A | Portage Learning
1. Which statement accurately describes the function of the plasma membrane?
A) It synthesizes proteins for cellular export
B) It acts as a selectively permeable barrier controlling material movement
C) It generates ATP through oxidative phosphorylation
D) It stores genetic information for cell division
Correct Answer: It acts as a selectively permeable barrier controlling material
movement
Rationale: The plasma membrane is a phospholipid bilayer with embedded proteins
that regulates the entry and exit of substances, maintaining the internal environment
of the cell. Protein synthesis occurs at ribosomes, ATP generation happens in
mitochondria, and genetic storage is the nucleus's role.
2. In the context of cellular transport, what is the primary mechanism by which
oxygen and carbon dioxide move between cells and capillaries?
A) Facilitated diffusion
B) Simple diffusion
C) Active transport
D) Vesicular transport
Correct Answer: Simple diffusion
Rationale: Small, nonpolar gases like oxygen and carbon dioxide diffuse passively
down their concentration gradients directly through the phospholipid bilayer. This
,process requires no energy or carrier proteins, distinguishing it from facilitated
diffusion and active transport.
3. A researcher observes a cell that possesses a distinct nucleus and several
membrane-bound organelles. Based on these characteristics, how should this cell be
classified?
A) Prokaryotic
B) Eukaryotic
C) Bacterial
D) Viral
Correct Answer: Eukaryotic
Rationale: Eukaryotic cells are defined by a true nucleus enclosed within a
membrane and the presence of membrane-bound organelles such as mitochondria
and the endoplasmic reticulum. Prokaryotic cells, like bacteria, lack a nucleus and
these organelles.
4. What is the primary role of the sodium-potassium pump in maintaining cellular
homeostasis?
A) Moving sodium and potassium down their concentration gradients
B) Exporting three sodium ions and importing two potassium ions using ATP
C) Transporting glucose into the cell along with sodium
D) Regulating intracellular calcium concentration
Correct Answer: Exporting three sodium ions and importing two potassium ions
using ATP
, Rationale: The sodium-potassium pump (Na+/K+-ATPase) uses ATP to actively
transport three sodium ions out of the cell and two potassium ions into the cell
against their concentration gradients. This maintains the resting membrane potential
and cell volume.
5. A white blood cell engulfs a bacterium by forming a vesicle around it. What is this
process called?
A) Pinocytosis
B) Phagocytosis
C) Exocytosis
D) Receptor-mediated endocytosis
Correct Answer: Phagocytosis
Rationale: Phagocytosis is a form of endocytosis where the cell engulfs large
particles such as bacteria or dead cells. Pinocytosis involves the ingestion of fluids
and solutes, while exocytosis is the release of materials from the cell.
6. During which phase of the cell cycle does DNA replication occur?
A) G1 phase
B) S phase
C) G2 phase
D) M phase
Correct Answer: S phase
Rationale: The S phase (synthesis phase) is when DNA replication takes place,
ensuring that each daughter cell receives a complete set of chromosomes. The G1
