BIO 207 EXAM 2 QUESTIONS AND ANSWERS
WITH VERIFIED SOLUTIONS 100% CORRECT
Between cones and rods, which ones are responsible for visual acuity
and sensitivity and why? - correct answer- Cones because they
respond to colors and rods don't because they function at only one
wavelength. Cones also have their own bipolar and ganglionic cells while
rods have to share them.
Describe ion gating in axons - correct answer- Changes in membrane
potential are controlled by changes in the flow of ions through ion
channels.
K+ has two types of channels:
Not gated (always open); sometimes called "leaky" K+ channels
Voltage-gated K+ channels; open when a particular membrane potential
is reached
Na+ has only voltage-gated channels that are closed at rest.
The membrane is less permeable to Na+ at rest.
How are action potentials transmitted down an axon? - correct answer-
Na+ ions are conducted to an adjacent area where they lower the
membrane potential to its threshold and then trigger an action potential.
,The original active area returns to its rest in potential and the new active
area triggers an action potential in the adjacent inactive area.
How are the images of moving objects focused? - correct answer-
The contraction of the ciliary muscles allows the eyes to focus on distant,
close, and moving objects
How do amphetamines work? - correct answer- Amphetamines
work by stimulating norepinephrine pathways in the brain (associated
with arousal).
How do left and right cerebral hemispheres communicate and what are
their functional specialties? - correct answer- They communicate
through the Corpus Callosum, which is a bridge between the two
hemispheres
Left Hemi - language, logic, math, controls right side, Broca's area and
Wernicke's area
Right Hemi - nonverbal (musical, perceptual, art, pictures) pattern
recognition, processes info holistically rather than individually
How do you distinguish between spatial and temporal summation? -
correct answer- Spatial summation occurs due to convergence of
signals onto a single postsynaptic neuron. Temporal summation is due to
successive waves of neurotransmitter released from the same neuron.
, How do you distinguish sensory deafness from conductive deafness and
what factors can cause conductive deafness? - correct answer-
Conductive deafness - impaired transmission of sound waves through
the middle ear due to excessive fluid accumulation or immobilization of
the stapes due to ostosclerosis (bone resorption and deposition). This
impairment covers all sound frequencies. Sensory deafness - caused by
nerve damage, usually attributed to exposure to very loud sounds, may
impair hearing of only certain frequencies
How does acetylcholine (Ach) produce EPSP (Nicotinic Ach receptors)
and IPSP (Muscuranic Ach receptors)? - correct answer- For EPSP,
ACh binds to the nicotine receptor and then lets in Na+ while K+ escapes.
This produces a small EPSP which may produce a threshold potential
leading to an action potential. For IPSP, the ACh receptor is linked to a
K+ channel through G-protein intermediates. When ACh binds to this
receptor a change in the conformation (shape) of the receptor occurs,
which activates G-protein operated K+ channel. K+ leaves the cell and
leads to an IPSP.
How is Acetylcholine (ACh) action terminated? - correct answer- It is
removed by acetylcholinesterase (AChE), which is located on cleft in
post-synaptic membrane.
How is color vision perceived? - correct answer- Trichromatic
Theory: There are three different types of cones, red, green and blue
WITH VERIFIED SOLUTIONS 100% CORRECT
Between cones and rods, which ones are responsible for visual acuity
and sensitivity and why? - correct answer- Cones because they
respond to colors and rods don't because they function at only one
wavelength. Cones also have their own bipolar and ganglionic cells while
rods have to share them.
Describe ion gating in axons - correct answer- Changes in membrane
potential are controlled by changes in the flow of ions through ion
channels.
K+ has two types of channels:
Not gated (always open); sometimes called "leaky" K+ channels
Voltage-gated K+ channels; open when a particular membrane potential
is reached
Na+ has only voltage-gated channels that are closed at rest.
The membrane is less permeable to Na+ at rest.
How are action potentials transmitted down an axon? - correct answer-
Na+ ions are conducted to an adjacent area where they lower the
membrane potential to its threshold and then trigger an action potential.
,The original active area returns to its rest in potential and the new active
area triggers an action potential in the adjacent inactive area.
How are the images of moving objects focused? - correct answer-
The contraction of the ciliary muscles allows the eyes to focus on distant,
close, and moving objects
How do amphetamines work? - correct answer- Amphetamines
work by stimulating norepinephrine pathways in the brain (associated
with arousal).
How do left and right cerebral hemispheres communicate and what are
their functional specialties? - correct answer- They communicate
through the Corpus Callosum, which is a bridge between the two
hemispheres
Left Hemi - language, logic, math, controls right side, Broca's area and
Wernicke's area
Right Hemi - nonverbal (musical, perceptual, art, pictures) pattern
recognition, processes info holistically rather than individually
How do you distinguish between spatial and temporal summation? -
correct answer- Spatial summation occurs due to convergence of
signals onto a single postsynaptic neuron. Temporal summation is due to
successive waves of neurotransmitter released from the same neuron.
, How do you distinguish sensory deafness from conductive deafness and
what factors can cause conductive deafness? - correct answer-
Conductive deafness - impaired transmission of sound waves through
the middle ear due to excessive fluid accumulation or immobilization of
the stapes due to ostosclerosis (bone resorption and deposition). This
impairment covers all sound frequencies. Sensory deafness - caused by
nerve damage, usually attributed to exposure to very loud sounds, may
impair hearing of only certain frequencies
How does acetylcholine (Ach) produce EPSP (Nicotinic Ach receptors)
and IPSP (Muscuranic Ach receptors)? - correct answer- For EPSP,
ACh binds to the nicotine receptor and then lets in Na+ while K+ escapes.
This produces a small EPSP which may produce a threshold potential
leading to an action potential. For IPSP, the ACh receptor is linked to a
K+ channel through G-protein intermediates. When ACh binds to this
receptor a change in the conformation (shape) of the receptor occurs,
which activates G-protein operated K+ channel. K+ leaves the cell and
leads to an IPSP.
How is Acetylcholine (ACh) action terminated? - correct answer- It is
removed by acetylcholinesterase (AChE), which is located on cleft in
post-synaptic membrane.
How is color vision perceived? - correct answer- Trichromatic
Theory: There are three different types of cones, red, green and blue
