BIOL251 Human Anatomy & Physiology I w/Lab 2026 |
Module 7 Exam | 70+ Questions and Answers
Institution: Portage Learning
Course: BIOL251 - Human Anatomy & Physiology I with Lab
Exam: Module 7 Exam Review | Lock Down Browser | 2026/2027
SECTION 1: CELLULAR TRANSPORT & OSMOSIS
Question 1
What is osmosis?
A) The diffusion of any molecule across a selectively permeable membrane
B) The diffusion of water molecules across a selectively permeable membrane from an
area of higher water concentration to lower water concentration
C) The active transport of sodium ions across the cell membrane
D) The movement of solutes from an area of higher solute concentration to lower solute
concentration
Correct Answer: B) The diffusion of water molecules across a selectively permeable
membrane from an area of higher water concentration to lower water
concentration
Rationale: Osmosis is specifically the passive movement of water across a selectively
permeable membrane. Water moves from an area of lower solute concentration (higher
water concentration) to an area of higher solute concentration (lower water concentration)
to achieve equilibrium.
,Question 2
Describe the effects of isotonic, hypertonic, and hypotonic solutions on human cells.
A) Isotonic - cells swell; Hypertonic - cells maintain volume; Hypotonic - cells shrink
B) Isotonic - cells maintain volume; Hypertonic - cells shrink; Hypotonic - cells swell
C) Isotonic - cells shrink; Hypertonic - cells swell; Hypotonic - cells maintain volume
D) Isotonic - cells maintain volume; Hypertonic - cells swell; Hypotonic - cells shrink
Correct Answer: B) Isotonic - cells maintain volume; Hypertonic - cells shrink;
Hypotonic - cells swell
Rationale: In an isotonic solution, the solute concentration is equal inside and outside the
cell, so water moves equally in both directions maintaining cell volume. In a hypertonic
solution, the extracellular environment has a higher solute concentration, causing water to
leave the cell, resulting in cell shrinkage (crenation). In a hypotonic solution, the
extracellular environment has a lower solute concentration, causing water to enter the cell,
resulting in swelling and potential lysis.
Question 3
What factors influence the rate of diffusion across a membrane?
A) Molecular size and charge
B) Temperature
C) Concentration gradient
D) All of the above
Correct Answer: D) All of the above
Rationale: The rate of diffusion across a membrane is influenced by multiple factors:
smaller molecules and those with appropriate charge move faster; higher temperatures
increase kinetic energy and diffusion rate; and a steeper concentration gradient increases
the rate of diffusion.
,Question 4
Which type of molecule can pass most easily through a protein-free phospholipid
bilayer?
A) Ions
B) Large polar molecules
C) Small polar molecules
D) Non-polar molecules
Correct Answer: D) Non-polar molecules
Rationale: Non-polar molecules (such as oxygen, carbon dioxide, and lipids) can easily
pass through the hydrophobic interior of the phospholipid bilayer. Ions and polar
molecules are repelled by the hydrophobic lipid tails and require protein channels or
carriers for transport.
Question 5
How does simple diffusion differ from facilitated diffusion?
A) Simple diffusion requires ATP; facilitated diffusion does not
B) Simple diffusion uses any part of a membrane; facilitated diffusion uses channels or
carriers in the membrane
C) Simple diffusion moves molecules against their gradient; facilitated diffusion moves
with the gradient
D) Simple diffusion requires carrier proteins; facilitated diffusion does not
Correct Answer: B) Simple diffusion uses any part of a membrane; facilitated
diffusion uses channels or carriers in the membrane
Rationale: Simple diffusion allows molecules to pass directly through the phospholipid
bilayer anywhere along the membrane. Facilitated diffusion relies on specific membrane
proteins (channel or carrier proteins) to assist molecule movement.
, Question 6
Describe the role of channel proteins and carrier proteins in facilitated diffusion.
A) Both channel and carrier proteins use ATP to move molecules against their gradient
B) Channel proteins act as open pores allowing specific molecules to freely pass; carrier
proteins change shape to transport molecules across the membrane
C) Channel proteins bind molecules and change shape; carrier proteins form open pores
D) Both proteins function identically and are interchangeable
Correct Answer: B) Channel proteins act as open pores allowing specific molecules
to freely pass; carrier proteins change shape to transport molecules across the
membrane
Rationale: Channel proteins form hydrophilic pores that allow specific ions or molecules to
pass through the membrane. Carrier proteins bind to the specific molecule, undergo a
conformational change, and release the molecule on the other side of the membrane.
Question 7
Explain the mechanism of exocytosis and provide an example of where it plays a crucial
role in human cells.
A) Exocytosis is the process of engulfing extracellular material; an example is a white
blood cell engulfing a bacterium
B) Exocytosis is the process of transporting neurotransmitters and proteins out of the
cell through an energy-dependent process; an example is neurotransmitter release at
synapses
C) Exocytosis is the passive movement of water across a membrane
D) Exocytosis is the uptake of fluids by the cell
Correct Answer: B) Exocytosis is the process of transporting neurotransmitters and
proteins out of the cell through an energy-dependent process; an example is
neurotransmitter release at synapses
Rationale: Exocytosis is an active transport process where vesicles fuse with the plasma
membrane to release their contents (neurotransmitters, hormones, proteins) outside the
cell. Neurotransmitter release at the synaptic cleft is a classic example of exocytosis.
Module 7 Exam | 70+ Questions and Answers
Institution: Portage Learning
Course: BIOL251 - Human Anatomy & Physiology I with Lab
Exam: Module 7 Exam Review | Lock Down Browser | 2026/2027
SECTION 1: CELLULAR TRANSPORT & OSMOSIS
Question 1
What is osmosis?
A) The diffusion of any molecule across a selectively permeable membrane
B) The diffusion of water molecules across a selectively permeable membrane from an
area of higher water concentration to lower water concentration
C) The active transport of sodium ions across the cell membrane
D) The movement of solutes from an area of higher solute concentration to lower solute
concentration
Correct Answer: B) The diffusion of water molecules across a selectively permeable
membrane from an area of higher water concentration to lower water
concentration
Rationale: Osmosis is specifically the passive movement of water across a selectively
permeable membrane. Water moves from an area of lower solute concentration (higher
water concentration) to an area of higher solute concentration (lower water concentration)
to achieve equilibrium.
,Question 2
Describe the effects of isotonic, hypertonic, and hypotonic solutions on human cells.
A) Isotonic - cells swell; Hypertonic - cells maintain volume; Hypotonic - cells shrink
B) Isotonic - cells maintain volume; Hypertonic - cells shrink; Hypotonic - cells swell
C) Isotonic - cells shrink; Hypertonic - cells swell; Hypotonic - cells maintain volume
D) Isotonic - cells maintain volume; Hypertonic - cells swell; Hypotonic - cells shrink
Correct Answer: B) Isotonic - cells maintain volume; Hypertonic - cells shrink;
Hypotonic - cells swell
Rationale: In an isotonic solution, the solute concentration is equal inside and outside the
cell, so water moves equally in both directions maintaining cell volume. In a hypertonic
solution, the extracellular environment has a higher solute concentration, causing water to
leave the cell, resulting in cell shrinkage (crenation). In a hypotonic solution, the
extracellular environment has a lower solute concentration, causing water to enter the cell,
resulting in swelling and potential lysis.
Question 3
What factors influence the rate of diffusion across a membrane?
A) Molecular size and charge
B) Temperature
C) Concentration gradient
D) All of the above
Correct Answer: D) All of the above
Rationale: The rate of diffusion across a membrane is influenced by multiple factors:
smaller molecules and those with appropriate charge move faster; higher temperatures
increase kinetic energy and diffusion rate; and a steeper concentration gradient increases
the rate of diffusion.
,Question 4
Which type of molecule can pass most easily through a protein-free phospholipid
bilayer?
A) Ions
B) Large polar molecules
C) Small polar molecules
D) Non-polar molecules
Correct Answer: D) Non-polar molecules
Rationale: Non-polar molecules (such as oxygen, carbon dioxide, and lipids) can easily
pass through the hydrophobic interior of the phospholipid bilayer. Ions and polar
molecules are repelled by the hydrophobic lipid tails and require protein channels or
carriers for transport.
Question 5
How does simple diffusion differ from facilitated diffusion?
A) Simple diffusion requires ATP; facilitated diffusion does not
B) Simple diffusion uses any part of a membrane; facilitated diffusion uses channels or
carriers in the membrane
C) Simple diffusion moves molecules against their gradient; facilitated diffusion moves
with the gradient
D) Simple diffusion requires carrier proteins; facilitated diffusion does not
Correct Answer: B) Simple diffusion uses any part of a membrane; facilitated
diffusion uses channels or carriers in the membrane
Rationale: Simple diffusion allows molecules to pass directly through the phospholipid
bilayer anywhere along the membrane. Facilitated diffusion relies on specific membrane
proteins (channel or carrier proteins) to assist molecule movement.
, Question 6
Describe the role of channel proteins and carrier proteins in facilitated diffusion.
A) Both channel and carrier proteins use ATP to move molecules against their gradient
B) Channel proteins act as open pores allowing specific molecules to freely pass; carrier
proteins change shape to transport molecules across the membrane
C) Channel proteins bind molecules and change shape; carrier proteins form open pores
D) Both proteins function identically and are interchangeable
Correct Answer: B) Channel proteins act as open pores allowing specific molecules
to freely pass; carrier proteins change shape to transport molecules across the
membrane
Rationale: Channel proteins form hydrophilic pores that allow specific ions or molecules to
pass through the membrane. Carrier proteins bind to the specific molecule, undergo a
conformational change, and release the molecule on the other side of the membrane.
Question 7
Explain the mechanism of exocytosis and provide an example of where it plays a crucial
role in human cells.
A) Exocytosis is the process of engulfing extracellular material; an example is a white
blood cell engulfing a bacterium
B) Exocytosis is the process of transporting neurotransmitters and proteins out of the
cell through an energy-dependent process; an example is neurotransmitter release at
synapses
C) Exocytosis is the passive movement of water across a membrane
D) Exocytosis is the uptake of fluids by the cell
Correct Answer: B) Exocytosis is the process of transporting neurotransmitters and
proteins out of the cell through an energy-dependent process; an example is
neurotransmitter release at synapses
Rationale: Exocytosis is an active transport process where vesicles fuse with the plasma
membrane to release their contents (neurotransmitters, hormones, proteins) outside the
cell. Neurotransmitter release at the synaptic cleft is a classic example of exocytosis.
