BIOLOGY 251 Lecture Exam 2 | Full Questions and Answers with Rationales | 2026/27 Update | 100%
Correct – WSU.
1. Which statement best describes the interaction between transverse tubules and
the sarcoplasmic reticulum during skeletal-muscle contraction?
A. T-tubule action potentials release acetylcholine, which activates SR receptors.
B. T-tubule action potentials release norepinephrine, which activates SR receptors.
C. T-tubule action potentials are detected by DHP receptors coupled to ryanodine receptors in
the SR, opening calcium-release channels.
D. T-tubule action potentials are detected by ryanodine receptors coupled to DHP receptors in
the SR.
E. T-tubule action potentials directly depolarize the SR and open its voltage-gated calcium
channels.
Correct answer: C
Rationale: DHP receptors in the T-tubule membrane act as voltage sensors. They interact
mechanically with ryanodine receptors in the sarcoplasmic reticulum, causing calcium release
into the cytoplasm.
2. Students with test anxiety often have an elevated heart rate during
examinations. Which autonomic division causes this response?
A. Sympathetic
B. Parasympathetic
C. Somatic
D. Voluntary
E. None of the above
Correct answer: A. Sympathetic
Rationale: Sympathetic “fight-or-flight” activity increases heart rate and cardiac contractility
during stress.
3. Which characteristic is not typically a specialization of the left cerebral
hemisphere?
A. Expression of language
B. Comprehension of language
C. Analytical reasoning
, D. Creativity
E. Logical reasoning
Correct answer: D. Creativity
Rationale: Language, analytical processing, and logical reasoning are generally associated with
the left hemisphere. Creativity and spatial or holistic processing are more strongly associated
with the right hemisphere.
4. The lens adjusts its refractive power to focus light from a near object through
what process?
A. Accommodation
B. Acclimation
C. Acclimatization
D. Telescoping
E. Refractometry
Correct answer: A. Accommodation
Rationale: Accommodation changes the curvature of the lens. For near vision, the lens becomes
more rounded and increases its refractive power.
5. What normally occurs when a doctor shines a light into a patient’s eye?
A. Parasympathetic activation contracts the outer radial iris muscle and constricts the pupil.
B. Sympathetic activation contracts the outer radial iris muscle and constricts the pupil.
C. Sympathetic activation contracts the outer radial iris muscle and dilates the pupil.
D. Parasympathetic activation contracts the inner circular iris muscle and constricts the pupil.
E. Parasympathetic activation contracts the outer radial iris muscle and dilates the pupil.
Correct answer: D
Rationale: Bright light activates the parasympathetic pupillary reflex. Contraction of the circular
sphincter pupillae constricts the pupil.
6. The sound-sensitive cells in the cochlear duct sit atop which membrane?
A. Vestibular membrane
B. Tympanic membrane
Correct – WSU.
1. Which statement best describes the interaction between transverse tubules and
the sarcoplasmic reticulum during skeletal-muscle contraction?
A. T-tubule action potentials release acetylcholine, which activates SR receptors.
B. T-tubule action potentials release norepinephrine, which activates SR receptors.
C. T-tubule action potentials are detected by DHP receptors coupled to ryanodine receptors in
the SR, opening calcium-release channels.
D. T-tubule action potentials are detected by ryanodine receptors coupled to DHP receptors in
the SR.
E. T-tubule action potentials directly depolarize the SR and open its voltage-gated calcium
channels.
Correct answer: C
Rationale: DHP receptors in the T-tubule membrane act as voltage sensors. They interact
mechanically with ryanodine receptors in the sarcoplasmic reticulum, causing calcium release
into the cytoplasm.
2. Students with test anxiety often have an elevated heart rate during
examinations. Which autonomic division causes this response?
A. Sympathetic
B. Parasympathetic
C. Somatic
D. Voluntary
E. None of the above
Correct answer: A. Sympathetic
Rationale: Sympathetic “fight-or-flight” activity increases heart rate and cardiac contractility
during stress.
3. Which characteristic is not typically a specialization of the left cerebral
hemisphere?
A. Expression of language
B. Comprehension of language
C. Analytical reasoning
, D. Creativity
E. Logical reasoning
Correct answer: D. Creativity
Rationale: Language, analytical processing, and logical reasoning are generally associated with
the left hemisphere. Creativity and spatial or holistic processing are more strongly associated
with the right hemisphere.
4. The lens adjusts its refractive power to focus light from a near object through
what process?
A. Accommodation
B. Acclimation
C. Acclimatization
D. Telescoping
E. Refractometry
Correct answer: A. Accommodation
Rationale: Accommodation changes the curvature of the lens. For near vision, the lens becomes
more rounded and increases its refractive power.
5. What normally occurs when a doctor shines a light into a patient’s eye?
A. Parasympathetic activation contracts the outer radial iris muscle and constricts the pupil.
B. Sympathetic activation contracts the outer radial iris muscle and constricts the pupil.
C. Sympathetic activation contracts the outer radial iris muscle and dilates the pupil.
D. Parasympathetic activation contracts the inner circular iris muscle and constricts the pupil.
E. Parasympathetic activation contracts the outer radial iris muscle and dilates the pupil.
Correct answer: D
Rationale: Bright light activates the parasympathetic pupillary reflex. Contraction of the circular
sphincter pupillae constricts the pupil.
6. The sound-sensitive cells in the cochlear duct sit atop which membrane?
A. Vestibular membrane
B. Tympanic membrane
