BIO 251 LATEST 2026 CORE EXAM TEST QUESTIONS
AND ANSWERS GUARANTEE A+
✔✔In order to focus light coming from a near source onto the retina, the lens adjusts its
refractive power (ability to bend light) through what process? - ✔✔accommodation
✔✔Which of the following defects in vision is INCORRECTLY matched with its cause? -
✔✔glaucoma: reduced eye fluid volume, and therefore, less eye pressure
✔✔The inner circular smooth muscle layer of the iris of the eye is controlled by
the_______nervous system and its contraction causes pupillary_______ -
✔✔parasympathetic: constriction
✔✔When you are scared, your pupils dilate to let more light enter your eye. Which of
the following statements best explains what causes this to occur? - ✔✔the sympathetic
nervous system is activated, which causes contraction of the outer radial muscle of the
iris and pupillary dilation.
✔✔Which of the following occurs during accommodation for near vision? - ✔✔The lens
becomes rounder, thus bending light waves to a greater extent to focus them onto the
retina
✔✔The ciliary muscle of the eye that controls the shape of the lens to regulate it's ability
to refract (bend) light waves is controlled by which branch of the nervous system? -
✔✔PNS
✔✔In the absence of light, photoreceptors in the retina release a neurotransmitter that
inhibits_______which in turn inhibit ganglion cells of the retina. - ✔✔bipolar cells of the
retina
✔✔When we enter a dark room, the amount of photopigment in
the_________photoreceptors is slowly______
so that these cells can now absorb enough light energy to see. This takes a few minutes
and is known as dark adaptation. - ✔✔rods : increased
✔✔What is the function of the middle ear ossicles? - ✔✔amplify sound waves as they
are transmitted from the middle to the inner ear
✔✔Which cell type in the inner ear is able to transduce sound waves into the electrical
signals which are sent to the brain? - ✔✔Hair cells
✔✔Where is the organ of Corti specifically located? - ✔✔scala media (cochlear duct) of
cochlea
, ✔✔The pitch (frequency) of sound is coded for by the______ - ✔✔information coming
from hair cells on the portion of basilar membrane that is vibrating most in response to a
certain sound frequency
✔✔Which of the following areas of the brain assists the cerebral cortex by helping to
coordinate movement? - ✔✔Cerebellum
✔✔Hunger and thirst centers are located in which area of the brain? - ✔✔Hypothalamus
✔✔What type of glial cell, i.e., neural support cell, is necessary for normal development
of
the blood-brain barrier? - ✔✔Astrocytes
✔✔True or False. The motor areas of your right cerebral cortex control the muscle on
the left side of your body due to the somatic nervous system pathways crossing over
from the right side to the left side. - ✔✔True
✔✔Calcium for contraction is stored in what region of skeletal muscle cells? -
✔✔Sarcoplasmic reticulum (SR)
✔✔In skeletal muscle cells, calcium binding to which regulatory protein component of
the thin myofilaments triggers contraction? - ✔✔Troponin
✔✔In skeletal muscle, the binding of calcium to troponin will directly allow which of the
following? - ✔✔the movement of tropomyosin, thereby exposing the myosin-binding site
on the actin molecule
✔✔What is the regulatory protein component of the thin myofilament that blocks the
myosin-binding site on the actin until moved out of the way during excitation-contraction
coupling? - ✔✔tropomyosin
✔✔In skeletal muscle contraction, the repeated, oscillating connections between the
myosin heads of the thick myofilaments and the actin of the thin myofilaments which
results a power stroke is called what? - ✔✔Crossbridge cycling
✔✔Which of the following detects the action potentials travelling down I tubules when a
muscle cell is stimulated to contract? - ✔✔dihydropyridine (DHP) receptor on the T
tubules
✔✔In skeletal muscle cells, what enzyme catalyzes the transfer of a phosphate group to
ADP to make ATP which can then be used to supply energy for muscle contraction? -
✔✔Creatine kinase (CK)
AND ANSWERS GUARANTEE A+
✔✔In order to focus light coming from a near source onto the retina, the lens adjusts its
refractive power (ability to bend light) through what process? - ✔✔accommodation
✔✔Which of the following defects in vision is INCORRECTLY matched with its cause? -
✔✔glaucoma: reduced eye fluid volume, and therefore, less eye pressure
✔✔The inner circular smooth muscle layer of the iris of the eye is controlled by
the_______nervous system and its contraction causes pupillary_______ -
✔✔parasympathetic: constriction
✔✔When you are scared, your pupils dilate to let more light enter your eye. Which of
the following statements best explains what causes this to occur? - ✔✔the sympathetic
nervous system is activated, which causes contraction of the outer radial muscle of the
iris and pupillary dilation.
✔✔Which of the following occurs during accommodation for near vision? - ✔✔The lens
becomes rounder, thus bending light waves to a greater extent to focus them onto the
retina
✔✔The ciliary muscle of the eye that controls the shape of the lens to regulate it's ability
to refract (bend) light waves is controlled by which branch of the nervous system? -
✔✔PNS
✔✔In the absence of light, photoreceptors in the retina release a neurotransmitter that
inhibits_______which in turn inhibit ganglion cells of the retina. - ✔✔bipolar cells of the
retina
✔✔When we enter a dark room, the amount of photopigment in
the_________photoreceptors is slowly______
so that these cells can now absorb enough light energy to see. This takes a few minutes
and is known as dark adaptation. - ✔✔rods : increased
✔✔What is the function of the middle ear ossicles? - ✔✔amplify sound waves as they
are transmitted from the middle to the inner ear
✔✔Which cell type in the inner ear is able to transduce sound waves into the electrical
signals which are sent to the brain? - ✔✔Hair cells
✔✔Where is the organ of Corti specifically located? - ✔✔scala media (cochlear duct) of
cochlea
, ✔✔The pitch (frequency) of sound is coded for by the______ - ✔✔information coming
from hair cells on the portion of basilar membrane that is vibrating most in response to a
certain sound frequency
✔✔Which of the following areas of the brain assists the cerebral cortex by helping to
coordinate movement? - ✔✔Cerebellum
✔✔Hunger and thirst centers are located in which area of the brain? - ✔✔Hypothalamus
✔✔What type of glial cell, i.e., neural support cell, is necessary for normal development
of
the blood-brain barrier? - ✔✔Astrocytes
✔✔True or False. The motor areas of your right cerebral cortex control the muscle on
the left side of your body due to the somatic nervous system pathways crossing over
from the right side to the left side. - ✔✔True
✔✔Calcium for contraction is stored in what region of skeletal muscle cells? -
✔✔Sarcoplasmic reticulum (SR)
✔✔In skeletal muscle cells, calcium binding to which regulatory protein component of
the thin myofilaments triggers contraction? - ✔✔Troponin
✔✔In skeletal muscle, the binding of calcium to troponin will directly allow which of the
following? - ✔✔the movement of tropomyosin, thereby exposing the myosin-binding site
on the actin molecule
✔✔What is the regulatory protein component of the thin myofilament that blocks the
myosin-binding site on the actin until moved out of the way during excitation-contraction
coupling? - ✔✔tropomyosin
✔✔In skeletal muscle contraction, the repeated, oscillating connections between the
myosin heads of the thick myofilaments and the actin of the thin myofilaments which
results a power stroke is called what? - ✔✔Crossbridge cycling
✔✔Which of the following detects the action potentials travelling down I tubules when a
muscle cell is stimulated to contract? - ✔✔dihydropyridine (DHP) receptor on the T
tubules
✔✔In skeletal muscle cells, what enzyme catalyzes the transfer of a phosphate group to
ADP to make ATP which can then be used to supply energy for muscle contraction? -
✔✔Creatine kinase (CK)
