BIOS 251 Exam 2 Questions and Answers with Rationales |
CHAMBERLAIN UNIVERSITY
Question 1. Apply the relevant course concept: A cell component is a tubulin-based hollow cytoskeletal
element important for organelle transport, cilia, and mitotic spindle. Identify it.
A. intermediate filament
B. motor protein
C. microtubule
D. microfilament
Correct Answer: C. microtubule
Explanation: The microtubule is a tubulin-based hollow cytoskeletal element important for organelle transport, cilia, and
mitotic spindle. Cytoskeletal elements differ in protein composition, diameter, and mechanical role. Together they support
cell architecture, movement, and intracellular organization. The alternatives are weaker because they do not match the
governing rule, definition, or facts presented in the question.
Question 2. Evaluate the information provided: A cell process is described as movement driven by energy
stored in an ion gradient created by another active transporter. Identify the transport mechanism.
A. secondary active transport
B. facilitated diffusion
C. osmosis
D. pinocytosis
Correct Answer: A. secondary active transport
Explanation: Secondary active transport is movement driven by energy stored in an ion gradient created by another active
transporter. Passive processes do not directly require ATP, whereas active or vesicular processes use cellular energy.
Transport mechanisms determine how nutrients, ions, water, and signaling molecules cross cell boundaries. The alternatives
are weaker because they do not match the governing rule, definition, or facts presented in the question.
Question 3. Identify the cell structure whose principal role is to fluid component of cytoplasm in which
many metabolic reactions occur. Determine the most defensible conclusion.
A. cytosol
B. peroxisome
C. cytoskeleton
D. plasma membrane
Correct Answer: A. cytosol
Explanation: The cytosol fluid component of cytoplasm in which many metabolic reactions occur. The distractor organelles
perform different tasks in synthesis, energy production, digestion, or structural support. Matching organelle structure with
function helps explain why different cell types contain different organelle abundances. The alternatives are weaker because
they do not match the governing rule, definition, or facts presented in the question.
Question 4. During pre-mRNA is modified before export from the nucleus, the key event occurs primarily
at the nucleus. Identify the process.
A. translation
B. transcription
C. RNA processing
D. DNA replication
Correct Answer: C. RNA processing
Explanation: Rna processing is the process in which pre-mRNA is modified before export from the nucleus. Gene
expression steps occur in a defined sequence and at characteristic cellular locations. Errors in these steps can alter protein
,production and therefore cell function. The alternatives are weaker because they do not match the governing rule,
definition, or facts presented in the question.
Question 5. Interpret the description: A membrane component helps stabilize membrane fluidity. Select the
component.
A. phospholipid bilayer
B. glycocalyx
C. integral membrane protein
D. cholesterol
Correct Answer: D. cholesterol
Explanation: The cholesterol helps stabilize membrane fluidity. Membrane components have distinct structural positions
and functional roles. Together they create a dynamic boundary that supports transport, signaling, and cell recognition. The
alternatives are weaker because they do not match the governing rule, definition, or facts presented in the question.
Question 6. Consider water crossing a selectively permeable membrane toward higher effective solute
concentration. Name the dominant transport mechanism.
A. simple diffusion
B. osmosis
C. secondary active transport
D. primary active transport
Correct Answer: B. osmosis
Explanation: The scenario describes osmosis. Transport is classified by whether movement follows a gradient, requires a
membrane protein, directly uses ATP, or uses vesicles. Correct classification predicts energy requirements and
directionality. The other choices are weaker because they reflect a different formula, input, interpretation, or arithmetic
result.
Question 7. Apply the relevant course concept: A membrane protein catalyzes a reaction at the membrane
surface. Identify its functional class.
A. channel protein
B. membrane enzyme
C. receptor protein
D. carrier protein
Correct Answer: B. membrane enzyme
Explanation: A membrane enzyme catalyzes a reaction at the membrane surface. Membrane proteins can transport, signal,
catalyze, or mechanically link cells. Their specialization turns the lipid bilayer into an active physiological interface. The
alternatives are weaker because they do not match the governing rule, definition, or facts presented in the question.
Question 8. Evaluate the information provided: Red blood cells are placed in a solution and show water
enters the cell, causing swelling and possible lysis. Classify the solution relative to the cells.
A. non-equilibrating suspension
B. isotonic
C. hypotonic
D. hypertonic
Correct Answer: C. hypotonic
Explanation: An hypotonic solution produces water enters the cell, causing swelling and possible lysis. Tonicity predicts the
direction of water movement based on nonpenetrating solute concentrations. This principle explains why inappropriate
intravenous solutions can damage cells. The alternatives are weaker because they do not match the governing rule,
definition, or facts presented in the question.
,Question 9. A secretory cell produces large amounts of protein hormone. An especially abundant organelle
would be the: Determine the most defensible conclusion.
A. lysosome
B. peroxisome
C. smooth endoplasmic reticulum
D. rough endoplasmic reticulum
Correct Answer: D. rough endoplasmic reticulum
Explanation: Protein destined for secretion is synthesized on ribosomes attached to rough ER. Smooth ER emphasizes lipid
metabolism, while lysosomes and peroxisomes specialize in degradation and oxidation. Cell ultrastructure often reflects the
dominant work performed by that cell. The alternatives are weaker because they do not match the governing rule,
definition, or facts presented in the question.
Question 10. Identify the cell structure whose principal role is to increase plasma-membrane surface area.
A. nucleus
B. Golgi apparatus
C. microvilli
D. plasma membrane
Correct Answer: C. microvilli
Explanation: The microvilli increase plasma-membrane surface area. The distractor organelles perform different tasks in
synthesis, energy production, digestion, or structural support. Matching organelle structure with function helps explain why
different cell types contain different organelle abundances. The alternatives are weaker because they do not match the
governing rule, definition, or facts presented in the question.
Question 11. Interpret the description: During mRNA codons are decoded to build a polypeptide, the key
event occurs primarily at the ribosome. Identify the process.
A. DNA replication
B. translation
C. RNA processing
D. transcription
Correct Answer: B. translation
Explanation: Translation is the process in which mRNA codons are decoded to build a polypeptide. Gene expression steps
occur in a defined sequence and at characteristic cellular locations. Errors in these steps can alter protein production and
therefore cell function. The alternatives are weaker because they do not match the governing rule, definition, or facts
presented in the question.
Question 12. Microscopy shows sister chromatids separate toward opposite poles. Identify the cell-cycle
stage or process.
A. anaphase
B. G2 phase
C. metaphase
D. telophase
Correct Answer: A. anaphase
Explanation: Anaphase is characterized by sister chromatids separate toward opposite poles. Neighboring cell-cycle stages
have different hallmark events. Correct sequencing of the cycle is essential for growth, tissue repair, and genomic stability.
The alternatives are weaker because they do not match the governing rule, definition, or facts presented in the question.
, Question 13. Apply the relevant course concept: A cell has duplicated its DNA but has not yet begun
mitosis. It is most likely in:
A. G1 phase
B. cytokinesis
C. S phase
D. G2 phase
Correct Answer: D. G2 phase
Explanation: G2 follows S phase and precedes mitosis, allowing additional growth and checkpoint activity. G1 occurs
before DNA synthesis, while S is the period of replication itself. Cell-cycle checkpoints help prevent damaged DNA from
being propagated. The alternatives are weaker because they do not match the governing rule, definition, or facts presented
in the question.
Question 14. Evaluate the information provided: Identify the cell structure whose principal role is to
synthesizes lipids and participates in detoxification and calcium storage.
A. Golgi apparatus
B. smooth endoplasmic reticulum
C. peroxisome
D. centrosome
Correct Answer: B. smooth endoplasmic reticulum
Explanation: The smooth endoplasmic reticulum synthesizes lipids and participates in detoxification and calcium storage.
The distractor organelles perform different tasks in synthesis, energy production, digestion, or structural support. Matching
organelle structure with function helps explain why different cell types contain different organelle abundances. The
alternatives are weaker because they do not match the governing rule, definition, or facts presented in the question.
Question 15. A membrane protein binds an extracellular signaling molecule and initiates a cellular
response. Identify its functional class. Determine the most defensible conclusion.
A. channel protein
B. membrane enzyme
C. receptor protein
D. carrier protein
Correct Answer: C. receptor protein
Explanation: A receptor protein binds an extracellular signaling molecule and initiates a cellular response. Membrane
proteins can transport, signal, catalyze, or mechanically link cells. Their specialization turns the lipid bilayer into an active
physiological interface. The alternatives are weaker because they do not match the governing rule, definition, or facts
presented in the question.
Question 16. During DNA sequence is used to synthesize RNA, the key event occurs primarily at the
nucleus. Identify the process.
A. RNA processing
B. translation
C. DNA replication
D. transcription
Correct Answer: D. transcription
Explanation: Transcription is the process in which DNA sequence is used to synthesize RNA. Gene expression steps occur
in a defined sequence and at characteristic cellular locations. Errors in these steps can alter protein production and therefore
cell function. The alternatives are weaker because they do not match the governing rule, definition, or facts presented in the
question.
CHAMBERLAIN UNIVERSITY
Question 1. Apply the relevant course concept: A cell component is a tubulin-based hollow cytoskeletal
element important for organelle transport, cilia, and mitotic spindle. Identify it.
A. intermediate filament
B. motor protein
C. microtubule
D. microfilament
Correct Answer: C. microtubule
Explanation: The microtubule is a tubulin-based hollow cytoskeletal element important for organelle transport, cilia, and
mitotic spindle. Cytoskeletal elements differ in protein composition, diameter, and mechanical role. Together they support
cell architecture, movement, and intracellular organization. The alternatives are weaker because they do not match the
governing rule, definition, or facts presented in the question.
Question 2. Evaluate the information provided: A cell process is described as movement driven by energy
stored in an ion gradient created by another active transporter. Identify the transport mechanism.
A. secondary active transport
B. facilitated diffusion
C. osmosis
D. pinocytosis
Correct Answer: A. secondary active transport
Explanation: Secondary active transport is movement driven by energy stored in an ion gradient created by another active
transporter. Passive processes do not directly require ATP, whereas active or vesicular processes use cellular energy.
Transport mechanisms determine how nutrients, ions, water, and signaling molecules cross cell boundaries. The alternatives
are weaker because they do not match the governing rule, definition, or facts presented in the question.
Question 3. Identify the cell structure whose principal role is to fluid component of cytoplasm in which
many metabolic reactions occur. Determine the most defensible conclusion.
A. cytosol
B. peroxisome
C. cytoskeleton
D. plasma membrane
Correct Answer: A. cytosol
Explanation: The cytosol fluid component of cytoplasm in which many metabolic reactions occur. The distractor organelles
perform different tasks in synthesis, energy production, digestion, or structural support. Matching organelle structure with
function helps explain why different cell types contain different organelle abundances. The alternatives are weaker because
they do not match the governing rule, definition, or facts presented in the question.
Question 4. During pre-mRNA is modified before export from the nucleus, the key event occurs primarily
at the nucleus. Identify the process.
A. translation
B. transcription
C. RNA processing
D. DNA replication
Correct Answer: C. RNA processing
Explanation: Rna processing is the process in which pre-mRNA is modified before export from the nucleus. Gene
expression steps occur in a defined sequence and at characteristic cellular locations. Errors in these steps can alter protein
,production and therefore cell function. The alternatives are weaker because they do not match the governing rule,
definition, or facts presented in the question.
Question 5. Interpret the description: A membrane component helps stabilize membrane fluidity. Select the
component.
A. phospholipid bilayer
B. glycocalyx
C. integral membrane protein
D. cholesterol
Correct Answer: D. cholesterol
Explanation: The cholesterol helps stabilize membrane fluidity. Membrane components have distinct structural positions
and functional roles. Together they create a dynamic boundary that supports transport, signaling, and cell recognition. The
alternatives are weaker because they do not match the governing rule, definition, or facts presented in the question.
Question 6. Consider water crossing a selectively permeable membrane toward higher effective solute
concentration. Name the dominant transport mechanism.
A. simple diffusion
B. osmosis
C. secondary active transport
D. primary active transport
Correct Answer: B. osmosis
Explanation: The scenario describes osmosis. Transport is classified by whether movement follows a gradient, requires a
membrane protein, directly uses ATP, or uses vesicles. Correct classification predicts energy requirements and
directionality. The other choices are weaker because they reflect a different formula, input, interpretation, or arithmetic
result.
Question 7. Apply the relevant course concept: A membrane protein catalyzes a reaction at the membrane
surface. Identify its functional class.
A. channel protein
B. membrane enzyme
C. receptor protein
D. carrier protein
Correct Answer: B. membrane enzyme
Explanation: A membrane enzyme catalyzes a reaction at the membrane surface. Membrane proteins can transport, signal,
catalyze, or mechanically link cells. Their specialization turns the lipid bilayer into an active physiological interface. The
alternatives are weaker because they do not match the governing rule, definition, or facts presented in the question.
Question 8. Evaluate the information provided: Red blood cells are placed in a solution and show water
enters the cell, causing swelling and possible lysis. Classify the solution relative to the cells.
A. non-equilibrating suspension
B. isotonic
C. hypotonic
D. hypertonic
Correct Answer: C. hypotonic
Explanation: An hypotonic solution produces water enters the cell, causing swelling and possible lysis. Tonicity predicts the
direction of water movement based on nonpenetrating solute concentrations. This principle explains why inappropriate
intravenous solutions can damage cells. The alternatives are weaker because they do not match the governing rule,
definition, or facts presented in the question.
,Question 9. A secretory cell produces large amounts of protein hormone. An especially abundant organelle
would be the: Determine the most defensible conclusion.
A. lysosome
B. peroxisome
C. smooth endoplasmic reticulum
D. rough endoplasmic reticulum
Correct Answer: D. rough endoplasmic reticulum
Explanation: Protein destined for secretion is synthesized on ribosomes attached to rough ER. Smooth ER emphasizes lipid
metabolism, while lysosomes and peroxisomes specialize in degradation and oxidation. Cell ultrastructure often reflects the
dominant work performed by that cell. The alternatives are weaker because they do not match the governing rule,
definition, or facts presented in the question.
Question 10. Identify the cell structure whose principal role is to increase plasma-membrane surface area.
A. nucleus
B. Golgi apparatus
C. microvilli
D. plasma membrane
Correct Answer: C. microvilli
Explanation: The microvilli increase plasma-membrane surface area. The distractor organelles perform different tasks in
synthesis, energy production, digestion, or structural support. Matching organelle structure with function helps explain why
different cell types contain different organelle abundances. The alternatives are weaker because they do not match the
governing rule, definition, or facts presented in the question.
Question 11. Interpret the description: During mRNA codons are decoded to build a polypeptide, the key
event occurs primarily at the ribosome. Identify the process.
A. DNA replication
B. translation
C. RNA processing
D. transcription
Correct Answer: B. translation
Explanation: Translation is the process in which mRNA codons are decoded to build a polypeptide. Gene expression steps
occur in a defined sequence and at characteristic cellular locations. Errors in these steps can alter protein production and
therefore cell function. The alternatives are weaker because they do not match the governing rule, definition, or facts
presented in the question.
Question 12. Microscopy shows sister chromatids separate toward opposite poles. Identify the cell-cycle
stage or process.
A. anaphase
B. G2 phase
C. metaphase
D. telophase
Correct Answer: A. anaphase
Explanation: Anaphase is characterized by sister chromatids separate toward opposite poles. Neighboring cell-cycle stages
have different hallmark events. Correct sequencing of the cycle is essential for growth, tissue repair, and genomic stability.
The alternatives are weaker because they do not match the governing rule, definition, or facts presented in the question.
, Question 13. Apply the relevant course concept: A cell has duplicated its DNA but has not yet begun
mitosis. It is most likely in:
A. G1 phase
B. cytokinesis
C. S phase
D. G2 phase
Correct Answer: D. G2 phase
Explanation: G2 follows S phase and precedes mitosis, allowing additional growth and checkpoint activity. G1 occurs
before DNA synthesis, while S is the period of replication itself. Cell-cycle checkpoints help prevent damaged DNA from
being propagated. The alternatives are weaker because they do not match the governing rule, definition, or facts presented
in the question.
Question 14. Evaluate the information provided: Identify the cell structure whose principal role is to
synthesizes lipids and participates in detoxification and calcium storage.
A. Golgi apparatus
B. smooth endoplasmic reticulum
C. peroxisome
D. centrosome
Correct Answer: B. smooth endoplasmic reticulum
Explanation: The smooth endoplasmic reticulum synthesizes lipids and participates in detoxification and calcium storage.
The distractor organelles perform different tasks in synthesis, energy production, digestion, or structural support. Matching
organelle structure with function helps explain why different cell types contain different organelle abundances. The
alternatives are weaker because they do not match the governing rule, definition, or facts presented in the question.
Question 15. A membrane protein binds an extracellular signaling molecule and initiates a cellular
response. Identify its functional class. Determine the most defensible conclusion.
A. channel protein
B. membrane enzyme
C. receptor protein
D. carrier protein
Correct Answer: C. receptor protein
Explanation: A receptor protein binds an extracellular signaling molecule and initiates a cellular response. Membrane
proteins can transport, signal, catalyze, or mechanically link cells. Their specialization turns the lipid bilayer into an active
physiological interface. The alternatives are weaker because they do not match the governing rule, definition, or facts
presented in the question.
Question 16. During DNA sequence is used to synthesize RNA, the key event occurs primarily at the
nucleus. Identify the process.
A. RNA processing
B. translation
C. DNA replication
D. transcription
Correct Answer: D. transcription
Explanation: Transcription is the process in which DNA sequence is used to synthesize RNA. Gene expression steps occur
in a defined sequence and at characteristic cellular locations. Errors in these steps can alter protein production and therefore
cell function. The alternatives are weaker because they do not match the governing rule, definition, or facts presented in the
question.
