BIOL 235 MIDTERM 1 EXAM – EXAM-STYLE QUESTIONS AND ANSWERS |
VERIFIED AND WELL DETAILED ANSWERS | PLUS RATIONALES | GUARANTEED
PASS | 2026/27 LATEST UPDATE | EXAM PREP | STUDY GUIDE | PRACTICE TEST
1. A cell is placed in a hypertonic solution. Which of the following best
describes the immediate net movement of water and the resulting effect on the
cell?
A. Water moves into the cell, causing it to swell and potentially lyse.
B. Water moves out of the cell, causing it to shrink and become crenated.
C. Water moves equally in and out of the cell, resulting in no net change in cell
volume.
D. Water moves out of the cell, but the cell wall prevents any change in cell
volume.
Correct Answer: B. Water moves out of the cell, causing it to shrink and
become crenated.
Rationale: A hypertonic solution has a higher concentration of solutes and a lower
concentration of water than the intracellular fluid. This creates an osmotic gradient
that drives water out of the cell, leading to cell shrinkage, or crenation. Option A
describes a hypotonic environment. Option C describes an isotonic environment.
Option D is incorrect because animal cells, which are the primary subject of this
context, do not have a rigid cell wall to prevent volume changes.
,2. Which type of tissue is characterized by cells that are tightly packed with
little to no extracellular matrix and is primarily responsible for forming barriers
and linings?
A. Connective tissue
B. Muscle tissue
C. Nervous tissue
D. Epithelial tissue
Correct Answer: D. Epithelial tissue
Rationale: Epithelial tissue is defined by its closely packed cells with minimal
extracellular matrix, forming sheets that cover body surfaces and line internal
cavities. Connective tissue (A) is characterized by abundant extracellular matrix.
Muscle tissue (B) is specialized for contraction. Nervous tissue (C) is specialized for
conducting electrical impulses.
3. Which of the following describes the primary function of the Golgi
apparatus?
A. Synthesis of ribosomal RNA
B. Modification, sorting, and packaging of proteins for secretion or delivery to
other organelles
C. Production of adenosine triphosphate (ATP) through cellular respiration
D. Intracellular digestion of worn-out organelles and foreign substances
Correct Answer: B. Modification, sorting, and packaging of proteins for
secretion or delivery to other organelles
,Rationale: The Golgi apparatus acts as the cell's post office, receiving proteins and
lipids from the endoplasmic reticulum, modifying them (e.g., adding carbohydrates),
and sorting them for transport to their final destinations. Option A is a function of
the nucleolus. Option C describes mitochondria. Option D describes lysosomes.
4. A patient has a genetic condition that prevents the formation of functional
desmosomes. Which of the following is the most likely clinical manifestation?
A. Inability of the stomach lining to secrete digestive enzymes
B. Weakening of the skin and cardiac muscle, making them prone to tearing
under mechanical stress
C. Failure of the immune system to recognize foreign pathogens
D. Impaired conduction of nerve impulses from the brain to skeletal muscles
Correct Answer: B. Weakening of the skin and cardiac muscle, making them
prone to tearing under mechanical stress
Rationale: Desmosomes are cell junctions that anchor cells together, providing
mechanical strength to tissues that experience significant stress, such as the
epidermis and cardiac muscle. A failure of desmosomes would compromise this
structural integrity. Options A, C, and D are not directly related to the mechanical
linking function of desmosomes.
5. During the process of transcription, which molecule is synthesized directly
from a DNA template?
A. Protein
B. Transfer RNA (tRNA)
, C. Ribosomal RNA (rRNA)
D. Messenger RNA (mRNA)
Correct Answer: D. Messenger RNA (mRNA)
Rationale: Transcription is the process by which the genetic information in DNA is
copied into a complementary mRNA molecule. This mRNA then carries the code to
the ribosome for translation into a protein. While tRNA and rRNA are also
transcribed from DNA, the primary product of transcription that carries the protein-
coding sequence is mRNA. Option A is the product of translation.
6. A patient is diagnosed with hyperkalemia. Which of the following would be
an expected effect on the resting membrane potential of a typical neuron?
A. The resting membrane potential would become more negative
(hyperpolarized).
B. The resting membrane potential would become more positive (depolarized)
and closer to threshold.
C. The resting membrane potential would remain unchanged due to the sodium-
potassium pump's ability to compensate.
D. The resting membrane potential would become more dependent on calcium
ions.
Correct Answer: B. The resting membrane potential would become more
positive (depolarized) and closer to threshold.
Rationale: An increase in extracellular potassium (hyperkalemia) reduces the
concentration gradient for potassium to leave the cell. This means less positive
charge leaves the cell, making the interior less negative (i.e., depolarized). This
VERIFIED AND WELL DETAILED ANSWERS | PLUS RATIONALES | GUARANTEED
PASS | 2026/27 LATEST UPDATE | EXAM PREP | STUDY GUIDE | PRACTICE TEST
1. A cell is placed in a hypertonic solution. Which of the following best
describes the immediate net movement of water and the resulting effect on the
cell?
A. Water moves into the cell, causing it to swell and potentially lyse.
B. Water moves out of the cell, causing it to shrink and become crenated.
C. Water moves equally in and out of the cell, resulting in no net change in cell
volume.
D. Water moves out of the cell, but the cell wall prevents any change in cell
volume.
Correct Answer: B. Water moves out of the cell, causing it to shrink and
become crenated.
Rationale: A hypertonic solution has a higher concentration of solutes and a lower
concentration of water than the intracellular fluid. This creates an osmotic gradient
that drives water out of the cell, leading to cell shrinkage, or crenation. Option A
describes a hypotonic environment. Option C describes an isotonic environment.
Option D is incorrect because animal cells, which are the primary subject of this
context, do not have a rigid cell wall to prevent volume changes.
,2. Which type of tissue is characterized by cells that are tightly packed with
little to no extracellular matrix and is primarily responsible for forming barriers
and linings?
A. Connective tissue
B. Muscle tissue
C. Nervous tissue
D. Epithelial tissue
Correct Answer: D. Epithelial tissue
Rationale: Epithelial tissue is defined by its closely packed cells with minimal
extracellular matrix, forming sheets that cover body surfaces and line internal
cavities. Connective tissue (A) is characterized by abundant extracellular matrix.
Muscle tissue (B) is specialized for contraction. Nervous tissue (C) is specialized for
conducting electrical impulses.
3. Which of the following describes the primary function of the Golgi
apparatus?
A. Synthesis of ribosomal RNA
B. Modification, sorting, and packaging of proteins for secretion or delivery to
other organelles
C. Production of adenosine triphosphate (ATP) through cellular respiration
D. Intracellular digestion of worn-out organelles and foreign substances
Correct Answer: B. Modification, sorting, and packaging of proteins for
secretion or delivery to other organelles
,Rationale: The Golgi apparatus acts as the cell's post office, receiving proteins and
lipids from the endoplasmic reticulum, modifying them (e.g., adding carbohydrates),
and sorting them for transport to their final destinations. Option A is a function of
the nucleolus. Option C describes mitochondria. Option D describes lysosomes.
4. A patient has a genetic condition that prevents the formation of functional
desmosomes. Which of the following is the most likely clinical manifestation?
A. Inability of the stomach lining to secrete digestive enzymes
B. Weakening of the skin and cardiac muscle, making them prone to tearing
under mechanical stress
C. Failure of the immune system to recognize foreign pathogens
D. Impaired conduction of nerve impulses from the brain to skeletal muscles
Correct Answer: B. Weakening of the skin and cardiac muscle, making them
prone to tearing under mechanical stress
Rationale: Desmosomes are cell junctions that anchor cells together, providing
mechanical strength to tissues that experience significant stress, such as the
epidermis and cardiac muscle. A failure of desmosomes would compromise this
structural integrity. Options A, C, and D are not directly related to the mechanical
linking function of desmosomes.
5. During the process of transcription, which molecule is synthesized directly
from a DNA template?
A. Protein
B. Transfer RNA (tRNA)
, C. Ribosomal RNA (rRNA)
D. Messenger RNA (mRNA)
Correct Answer: D. Messenger RNA (mRNA)
Rationale: Transcription is the process by which the genetic information in DNA is
copied into a complementary mRNA molecule. This mRNA then carries the code to
the ribosome for translation into a protein. While tRNA and rRNA are also
transcribed from DNA, the primary product of transcription that carries the protein-
coding sequence is mRNA. Option A is the product of translation.
6. A patient is diagnosed with hyperkalemia. Which of the following would be
an expected effect on the resting membrane potential of a typical neuron?
A. The resting membrane potential would become more negative
(hyperpolarized).
B. The resting membrane potential would become more positive (depolarized)
and closer to threshold.
C. The resting membrane potential would remain unchanged due to the sodium-
potassium pump's ability to compensate.
D. The resting membrane potential would become more dependent on calcium
ions.
Correct Answer: B. The resting membrane potential would become more
positive (depolarized) and closer to threshold.
Rationale: An increase in extracellular potassium (hyperkalemia) reduces the
concentration gradient for potassium to leave the cell. This means less positive
charge leaves the cell, making the interior less negative (i.e., depolarized). This
