LS 7C - Part 1 Flashcards
1
Q
What happens to a signal after it binds the receptor?
A. It stays bound until the receptor is destroyed
B. It eventually dissociates from the receptor
C. It is eventually destroyed by the receptor
D. It dissociates from the receptor when a termination signal is received
A
B. It eventually dissociates from the receptor
2
Q
Why do the functions of many receptor kinases depend on the fluid nature of the plasma membrane?
A. The activation of enzyme pathways requires a fluid membrane.
B. Binding of ligand to the receptor requires a fluid membrane. C. The receptor monomers must move together and dimerize to be activated.
D. Phosphorylation requires a fluid membrane.
A
C. The receptor monomers must move together and dimerize to be activated.
3
Q
A decrease in cell adhesion, by the introduction of an experimental substance to a tissue, compromises the strength of the tissue. Which cell junction would MOST likely be affected if a tissue is treated with this experimental substance?
A. adherens junctions
B. gap junctions
C. hemidesmosomes
D. tight junctions
A
A. adherens junctions
4
Q
Which of the following junctions would you predict to be most important for the function of the bladder?
A. adherens junctions
B. gap junctions
C. hemidesmosomes
D. tight junctions
A
D. tight junctions
5
Q
Older individuals have fragile skin that causes bed sores. The outer layer of skin can detach and blister in response to friction. Increased susceptibility to blister formation is caused by the loss of which component in the skin?
A. Skin signal pathway transducers
B. Cell cytoskeleton proteins
C. Cell adhesion molecules
D. Extracellular matrix proteins
A
D. Extracellular matrix proteins
6
Q
True or False: The signal can only be terminated in one location in the cell.
A
False
7
Q
Endocrine Signaling:
A. Is contact dependent
B. Signals to nearby cells through diffusion
C. Travels through the circulatory system
D. Is a type of signaling whereby the cell signals to receptors on its own cell membrane
A
C. Travels through the circulatory system
8
Q
Name a type of signaling molecule used in Paracrine Signaling.
A
Usually small, water-soluble molecules such as Growth Factor
9
Q
When is a time during development that Autocrine Signaling is important?
A
During the development of the embryo (for instance, to maintain specialization after differentiation of cell types.)
10
Q
What type of change occurs in the protein at the ligand binding site?
A
Conformational Change
11
Q
What is an example of a hydrophobic molecule?
A
Steroid
12
Q
After a GCRP is activated, the alpha subunit attached to what protein?
A
Adenylyl Cyclase
13
Q
What is a Kinase?
A
An enzyme that catalyzes the transfer of a phosphate group from ATP to a substrate.
14
Q
Is a phosphorylated protein considered activated or deactivated?
A
Activated
15
Q
Do phosphotases add or remove a phosphate group? What is this process called?
A
Remove. Dephosphorylation.
16
Q
What is it called when two sides of a receptor kinase is activated and comes together?
A
Dimerization
17
Q
What do Ion channels provide?
A
A hydrophilic pathway
18
Q
What are two types of controls for Ion Channels?
A
Voltage-gated and Ligand-gated
19
Q
What determines how long a ligand will be bound to its receptor?
A
Binding Affinity
20
Q
What are the 3 layers of skin?
A
Epidermis, Basal Lamina, Dermis
21
Q
What is the function of the cytoskeleton?
A
It determines the shape of cells.
22
Q
What are 3 types of motor proteins?
A
Kinesin, Dynein, and Myosine
23
Q
What are the subunits of Microtubules, Microfilaments and Intermediate filaments?
A
Tubulin dimers, Actin monomers, diverse proteins
24
Q
What is a transmembrane protein called?
A
Cadhedrin
25
What allows adhesion to the extracellular matrix?
Integrins
26
Give several examples of the extracellular matrix.
Elastin, Collagen, Fibroblasts, Basal Lamina, Laminin
27
What are the 3 types of nerve cells?
Sensory neurons, interneurons, and motor neurons.
28
What is an astrocyte?
A star-shaped glial cell. Contributes to blood-brain barrier by surrounding blood vessels in the the brain, thus limiting the size of compounds that can diffuse from the blood to the brain.
29
Explain Membrane Potential.
The difference in charge between the exterior and interior of the cell membrane. Measure in volts. (Only muscle and nerve cells respond to potentials.)
30
At what end of the neuron does depolarization begin?
The terminal end of a dendrite.
31
Where must the signal be strong enough to initiate an action potential?
Axon Hillock
32
What type of receptors are Post-Synaptic Membrane Receptors?
Ligand-gated Ion Channels (accept neurotransmitters from the corresponding cell's axon terminal)
33
Is an Excitatory Postsynaptic Potential a positive or negative change in membrane potential? What is another name for this? What principle ion(s) is involved?
Positive, depolarization, Sodium (Na+), also Potassium (K+) in lesser amounts
34
Is an Inhibitory Postsynaptic Potential a positive or negative change in membrane potential? What is another name for this? What principle ion(s) is involved?
Negative, hyperpolarization, Cholride (Cl-)
35
What are the two divisions of the Autonomic nervous system?
Sympathetic (fight/flight), Parasympathetic (rest/digest)
36
Is the autonomic nervous system apart of the Peripheral or Central nervous system?
Peripheral
37
What are the 3 major brain regions?
Hindbrain, Midbrain, Forebrain
38
Name the major component in the Limbic system?
Hippocampus
39
Name 3 major regions in the Forebrain.
Cerebral cortex, thalamus, hypothalamus
40
Name 3 major regions of the Hindbrain.
Pons and medulla (part of brainstem), cerebellum
41
What is the Cerebellum responsible for?
Complex motor tasks, integrating sensory and motor information
42
What is the Thalamus responsible for?
It is a relay station for sensory information. Sends information to cerebrum.
43
What is the Hypothalamus responsible for?
It interacts with autonomic and endocrine system to regulate general physiological state of the body.
44
What is the Cerebrum?
The outer left and right hemispheres of the cerebral cortex.
45
What is the Limbic System responsible for?
It controls physiological drives, instincts, emotions, motivation, and a sense of reward. Major component is the Hippocampus.
46
From anterior to posterior, name the lobes and other regions that separate the 4 major lobes.
Frontal lobe, Primary Motor Cortex, Central Sulcus, Primary Somatosensory Cortex, Occipital lobe, Visual Cortex.
47
What is Grey Matter composed of?
Densely packed neuron cell bodies and dendrites. Highly folded, make up cortex. Around 4mm thick.
48
What is White Matter composed of?
Axons of cortisol neurons in interior of the brain. White appearance due to fatty myelin produced by glial cells surrounding the axons.
49
What does the Central Sulcus separate?
The primary motor cortex and the primary somatosensory cortex.
50
What is Long-Term Potentiation?
The persistent strengthening of synapses based on recent patterns of activity.
51
True or False: Resting potential is generated mainly by the outward movement of K+ ions from inside the cell.
True
52
True or False: The voltage changes shown in the figure are measured just across the plasma membrane
True
53
True or False: The changes in voltage seen at #2 and #4 in the figure are caused by similar movements, in the same direction, of the same types of ions across the membranes.
False
54
True or False: The trace in the figure is following the voltage change as it moves down the axon.
False
55
True or False: The voltage change shown in the figure is an all-or-nothing response.
True
56
True or False: Different ion channels are responsible for generating the voltage change seen at #2 and #4 in the figure.
True
57
True or False: All voltage changes along the plasma membrane of an axon have the characteristic shape shown above.
True
58
True or False: The changes in voltage shown in the figure are due to ligand-gated ion channels opening and closing along the axon.
False
59
True or False: An EPSP of sufficient strength to reach threshold occurred at #1 on the figure.
True
60
True or False: A membrane that has no K+ channels will have a resting membrane potential that is higher than the one shown on the figure.
True
61
Imagine you genetically engineered a neuron to produce voltage-gated Na+ and K+ channels that opened at the same time in response to a change in voltage. How would that change the recording shown in the figure?
## Footnote
A. The peak voltage would be higher.
B. The peak would occur over a longer period of time.
C. Threshold values would increase.
D. The period of hyperpolarization would be longer.
E. No action potential would be generated.
E. No action potential would be generated.
62
Dilated pupils, inhibited digestive activity, increased respiratory rate, and release of glucose from the liver are all signs of activity of:
A. the sympathetic division of the autonomic system.
B. both divisions of the autonomic nervous system.
C. the somatic nervous system.
D. the parasympathetic division of the autonomic system.
A. the sympathetic division of the autonomic system.
63
What effect does the nervous system have on the heart rate?
A. Stimulation by sympathetic nerves sets the resting heart rate of the pacemaker cells in the SA node.
B. Stimulation by parasympathetic nerves causes the heart rate to slow down.
C. The nervous system does not directly affect the heart rate.
D. Stimulation by either the sympathetic or parasympathetic nerves causes pacemaker cells in the SA node to depolarize more slowly.
E. Stimulation by sympathetic nerves causes the pacemaker cells of the AV node to depolarize more rapidly than the pacemaker cells of the SA node.
B. Stimulation by parasympathetic nerves causes the heart rate to slow down.
64
Which of the following is an example of the effector's role in maintaining homeostasis?
A. decrease in body temperature on a cold day
B. increased sweating on a hot summer day
C. vasodilation on a cold winter day
D. increased body temperature during a workout
B. increased sweating on a hot summer day
65
Imagine you created a toxin such that when a neuron fired an action potential, the toxin would bind immediately to the sodium-potassium pump at the top of the action potential, but the sodium and potassium channels would still function. What process(es) would be affected?
A. maintaining resting potential and returning to resting potential after the hyperpolarization phase of an action potential
B. the hyperpolarization phase of an action potential
C. returning to resting potential after the hyperpolarization phase of an action potential
D. maintaining resting potential
E. the depolarization phase of an action potential
A. maintaining resting potential and returning to resting potential after the hyperpolarization phase of an action potential
66
An interneuron may receive multiple stimuli from the same sensory neuron over a very short period of time. The firing rate of the receiving neuron is proportional to the number of signals received from the sensory neuron over time. Of which of the following is this an example?
A. action potential
B. hyperpolarization
C. spatial summation
D. temporal summation
D. temporal summation
67
Imagine that you are talking with one of your friends about your biology course. He states that the somatic nervous system is subdivided into sympathetic and parasympathetic components, and is responsible for involuntary responses. Is this statement correct?
A. No, the somatic nervous system is responsible for voluntary responses, and is not subdivided into sympathetic and parasympathetic components.
B. No, although the somatic nervous system does have both sympathetic and parasympathetic subdivisions, it is responsible for voluntary responses.
C. No, although the somatic nervous system controls involuntary responses, it is the autonomic nervous system that is subdivided into parasympathetic and sympathetic components.
D. Yes, this statement is correct. The somatic nervous system has both sympathetic and parasympathetic components and controls involuntary responses.
A. No, the somatic nervous system is responsible for voluntary responses, and is not subdivided into sympathetic and parasympathetic components.
68
What does this negative resting potential mean?
A. The inside (ICF) of the axon is more negatively charged than the outside (ECF)
B. The outside of the axon (ECF) is more negatively charged than the inside (ICF)
A. The inside (ICF) of the axon is more negatively charged than the outside (ECF)
Potential = Inside - Outside
69
If a membrane were freely permeable to allcharged molecules, then the resting membrane potential would be \_\_\_\_\_\_\_\_\_.
A. Positive
B. Negative
C. Zero
C. Zero
70
A cell with a resting membrane potential of -70 mV suddenly becomes more permeable to Ca2+ ions. This cell will
A. Hyperpolarize
B. Depolarize
C. Neither (membrane potential will not change)
B. Depolarize
71
What kind(s) of ion channels would you expect to find in the plasma membraneof a neuron’s dendrites?
A. Ligand-gated ion channels only
B. Voltage-gated ion channels only
C. Both of these channels
A. Ligand-gated ion channels only
72
Which of the following best describes what is happening during Region 1 of the action potential?
A. Hyperpolarization due to cations leaving the cell
B. Depolarization due to cations leaving the cell
C. Hyperpolarization due to cations entering the cell
D. Depolarization due to cations entering the cell
D. Depolarization due to cations entering the cell
## Footnote
1. Sodium ions enter the cell, making the inside of the cell more positively charged than the outside
73
Which of the following best describes what is happening during Region 2 of the action potential?
A. Repolarization due to cations leaving the cell
B. Repolarization due to cations entering the cell
A. Repolarization due to cations leaving the cell
## Footnote
2. Potassium ions leave the cell, making the inside of the cell more negatively charged than the outside
74
Which of the following best describes what is happening during Region 3 of the action potential?
A. Hyperpolarization due to cations leaving the cell
B. Depolarization due to cations leaving the cell
C. Hyperpolarization due to cations entering the cell
D. Depolarization due to cations entering the cell
A. Hyperpolarization due to cations leaving the cell
## Footnote
3. Potassium ions continue to leave the cell, causing an overshoot of the resting membrane potential
75
Multiple sclerosis is a disease in which the myelin surrounding neurons in the brain and spinal cord are damaged. Without myelin, the rate of action potential propagation in these neurons will most likely \_\_\_\_\_\_.
A. Increase
B. Decrease
C. Not change
B. Decrease
76
Serotonin is a neurotransmitter. Selective serotonin reuptake inhibitors (SSRIs) block the function of serotonin reuptake transporters.
Taking an SSRI will cause the average concentrationof serotonin found in synaptic clefts to...
A. Increase
B. Decrease
C. Not change
A. Increase
77
Selective serotonin reuptake inhibitors (SSRIs) block the function of serotonin reuptake transporters.
Increased levels of serotonin in the synaptic cleft will most likely cause the ____________ neuron to __________ the frequency of action potentials
A. Presynaptic; increase
B. Presynaptic; decrease
C. Postsynaptic; increase
D. Postsynaptic; decrease
C. Postsynaptic; increase
78
True or False:
Neuron A sends an EPSP to Neuron D at the same time that Neuron C sends an IPSP to Neuron D.
The EPSP and IPSP will be spatially summed.
True
79
True or False:
Neuron A sends an EPSP to Neuron D at the same time that Neuron C sends an IPSP to Neuron D.
The IPSP will cause the region of Neuron D near the synapse to become hyperpolarized.
True
80
True or False:
Neuron A sends an EPSP to Neuron D at the same time that Neuron C sends an IPSP to Neuron D.
The IPSP will cause the axon of Neuron D to become hyperpolarized.
False
81
True or False: A drug that blocks the Ca2+ channels of the presynaptic neuron will prevent neurotransmitters from being released.
True
82
You are sitting on the couch and look down on your arm to see a tarantula:
Which branch of your autonomic nervous system will be activated?
A. Sympathetic
B. Parasympathetic
C. Both
D. Neither
A. Sympathetic
83
You are sitting on the couch and look down on your arm to see a tarantula:
All of the following are likely to occur EXCEPT:
A. Heart rate increases
B. Pupils dilate
C. Intestinal activity increases
C. Intestinal activity increases
84
If you were to read this text out loud, you would be using regions in all fourlobes of your brain except the...
A. Frontal Lobe
B. Occipital Lobe
C. Parietal Lobe
D. Temporal Lobe
E. None. All the areas are being used
E. None. All the areas are being used
85
A patient suffers a stroke that cuts of blood supply to a region in the cerebellum. Which of the following symptoms would you be most likely to observe in the patient?
A. Trouble maintaining balance
B. Inability to regulate body temperature
C. Problems seeing different colors
D. Muted sensory perception
A. Trouble maintaining balance
## Footnote
Follow-up: Damage to what regions of the brain could result in symptoms B, C, and D? Discuss with a neighbor.
86
A seizure in the primary motor cortex on the right side of the brain would most likely cause uncontrolled movement:
A. On the left side of the body
B. On the right side of the body
C. On both sides of the body
D. None of the above; a seizure in this region would not cause uncontrolled movement
A. On the left side of the body
87
You feel something brush past your arm. This sensation is sent to your brain by ______ neurons in the ______ nervous system.
A. Afferent; central
B. Efferent; central
C. Afferent; peripheral
D. Efferent; peripheral
C. Afferent; peripheral
88
You feel something brush past your arm. This sensation is perceived in yourbrain by...
A. Broca’s area
B. Wernicke’s area
C. The primary motor cortex
D. The somatosensory cortex
D. The somatosensory cortex
89
A post-synaptic neuron can undergo synaptic plasticity in response to repeated excitation from a pre-synaptic neuron. Protein synthesis and changes to the cytoskeleton will likely _______ the responsiveness of the post- synaptic neuron to subsequent stimulation.
A. Increase
B. Decrease
C. Not change
A. Increase
90
What does the Pituitary gland do and where is it located?
Produces a number of hormones, including growth hormone. Located beneath the brain.
91
What system is central to homeostasis?
The Endocrine System.
92
What is an effector?
An effector is an endocrine organ that releases hormone that causes a bodily response. Effector causes an "effect" in the body.
93
In the pancreas, what hormone do beta cells produce?
Insulin
94
In the pancreas, what hormone do alpha cells produce?
Glucagon
95
What is the body's response to insulin?
The muscle and liver cells take up glucose in the blood and either use it or store it in the form of glycogen. (Also, other body cells take up?)
96
What is the body's response to glucagon?
Glucagon stimulates the breakdown of glycogen (stored in the muscles and liver) into glucose and it's release from muscle and liver cells.
97
Do hormones work the exact same way in/on every cell they interact with?
No, depending on the type of cell, two cells that receive the hormone may go through two totally different processes depending on their function.
98
Do peptides/amines or steroids have longer lasting effects?
Steroids
99
What are hormone signalling pathways between endocrine glands and tissues?
Endocrine Axes (i.e. the Hypothalamic-Pituitary Axis)
100
Peptide hormone that signals (to receptors) to the anterior pituitary gland through blood vessels, leading to a much larger release of associated hormones from that organ.
Releasing factors
101
The central regulating gland of the endocrine system. Releases several hormones that coordinate action of many other endocrine glands and tissues.
Pituitary Gland
102
Main route by which nervous system signals are transmitted to the endocrine system.
Hypothalamus
103
This type of hormones controls the release of other hormones.
Tropic Hormones
104
In this example, what is acting as the homeostatic sensor?
A. Insulin/Glucagon
B. Glucose
C. Hypothalamus
D. Liver
E. Pancreas
D. Pancreas
105
Patients with Type 2 Diabetes produce insulin, but target cells do not respond to insulin and blood glucose levels become elevated. Which component of the feedback system is broken in these patients?
A. Stimulus
B. Sensor
C. Effector
D. Response
C. Effector
106
True or False: The Glucagon signaling pathway uses G-Protein Coupled Receptors.
True
107
True or False: The Gα subunit gains a phosphate atom from GTP.
True
108
You have discovered a mutation in adenylyl cyclase (AC) that prevents it from binding the G protein.
True or False: This mutation will lead to elevated cAMP levels in the absence of a signal.
False.
109
Based on the diagram, which protein is a phosphatase?
A. P1
B. P2
C. P3
D. P4
E. None of the above
D. P4
110
True or False: All of the proteins shown in the diagram are active when they are phosphorylated.
False.
111
A mutation in P4 causes it to be active all ofthe time (even when it’s unphosphorylated). What would be the most likely consequence of this mutation?
A. Glycogen will be made in the absence of insulin
B. Glycogen will not be made in the presence of insulin
C. Glycogen enzyme will be phosphorylated in the presence of insulin
D. P3 will be phosphorylated in the absence of insulin
A. Glycogen will be made in the absence of insulin
112
True or False: If the intracellular tyrosine amino acid residues of the RTK receptor are replaced, a functional signal transduction pathway can still be produced.
False
113
Why do the functions of many receptor kinases depend on the fluid nature of the plasma membrane?
A. The generation of cAMP requires a fluid membrane.
B. Binding of ligand to the receptor requires a fluid membrane.
C. The receptor monomers must move together and dimerize to be activated.
D. Phosphorylation requires a fluid membrane.
C. The receptor monomers must move together and dimerize to be activated.
114
Which of the following would shut the pathway off the most quickly?
A. Activating phosphatase that targets the receptor
B. Activating a phosphatase that targets P2
C. Activating a phosphatase that targets Glycogen Enzyme
A. Activating phosphatase that targets the receptor
115
True or False: Calcitonin and PTH bind to transport proteins in the blood.
False.
116
Calcitonin and PTH are peptide hormones. They most likely signal aresponse by...
A. Diffusing across the lipid bilayer to bind a cytoplasmic receptor
B. Binding a transmembrane receptor to activate a signal transduction pathway in the cytoplasm
C. Being transported into the cell to activate a signal transduction pathway in the cytoplasm
B. Binding a transmembrane receptor to activate a signal transduction pathway in the cytoplasm
117
If the body senses that calcium levels are too high, the amount of calcitonin secreted by the thyroid will most likely \_\_\_\_\_\_\_\_\_.
A. Increase
B. Decrease
C. Stay the same
A. Increase
118
You are examining a patient whose thyroid produces very little calcitonin. This patient will most likely have ______ calcium in his/her bones compared to a healthy individual.
A. More
B. Less
C. The same amount of
B. Less
119
Suppose the set point for blood calcium suddenly increased. As a result, the amount of PTH released by the parathyroid would \_\_\_\_\_\_\_\_\_\_.
A. Increase
B. Decrease
C. Stay the same
A. Increase
120
In the diagram below, which hormone(s) (if any) are released by neurons?
A. TRH
B. TSH
C. T3/T4
D. All of the above
E. None of the above
A. TRH
121
In the diagram below, which hormone(s) (if any) travel through blood vessels?
A. TRH
B. TSH
C. T3/T4
D. All of the above
E. None of the above
D. All of the above
122
Low levels of dietary iodine would cause the levels of T3 and T4 circulating in the bloodstream to \_\_\_\_\_\_\_\_.
A. Increase
B. Decrease
C. Not change
B. Decrease
123
Low levels of dietary iodine would cause the levels of TRH released from the hypothalamus to \_\_\_\_\_\_\_\_.
A. Increase
B. Decrease
C. Not change
A. Increase
124
Low levels of dietary iodine would cause the levels thyroglobulin in the thyroid to \_\_\_\_\_\_\_\_.
A. Increase
B. Decrease
C. Not change
A. Increase. When dietary iodine is too low, thyroglobulin accumulates and the thyroid becomes enlarged.
125
Feedback inhibition of GnRH will _________ follicular development.
A. Activate
B. Inhibit
C. Not affect
B. Inhibit. Inhibition of GnRH will suppress the release of FSH, which is necessary for promoting the development of new follicles.
126
The most common oral contraceptives are a combination of an estrogen and a progesterone. Which phase of the uterine cycle is mimicked by taking an oral contraceptive?
A. Early to mid-follicular phase
B. Late follicular phase
C. Early to mid-luteal phase
D. Late luteal phase
C. Early to mid-luteal phase
127
The most common oral contraceptives are a combination of an estrogen and a progesterone. Taking an oral contraceptive therefore _________ the level of LH circulating in the bloodstream.
A.Increases
B. Decreases
C.Does not change
B. Decreases
128
Which of the following would occur if the LH surge were suppressed?
A. Ovulation
B. An increase in progesterone
C. Both A and B
D. None of the above
D. None of the above
129
Atrazine inhibits the production of testosterone and enhances production of estrogen in frogs.
True or False: Atrazine acts as an aromatase inhibitor.
False
130
Aromatase activity is expected to be highest during which phase of the uterine cycle?
A. Early to mid-follicular phase
B.Late follicular phase
C.Early to mid-luteal phase
D.Late luteal phase
A. Early to mid-follicular phase
Androgens produced by theca cells will be converted to estrogens by aromatase in granulosa cells.
High levels of estrogen lead to positive feedback and the LH surge.
131
Aromatase deficiency results from autosomal recessive inheritance of mutations in
the CYP19A1\* gene. This condition would be characterized by ________ levels of \_\_\_\_\_\_\_\_\_.
CYP19A1 is the gene that codes for the enzyme aromatase
A. Increased; estrogen
B. Reduced; progesterone
C. Increased; testosterone
D. Reduced; testosterone
C. Increased; testosterone
132
What is a muscle fiber?
A single cell of muscle.
133
The basic contractile unit of a muscle is called the:
Sarcomere
134
Meniere's Disease is linked to an excessive volume of endolymph fluid. Where in the ear is endolymph found?
A. Outer ear
B. Middle ear
C. Inner ear
D. B and C
E. A, B, and C
C. Inner ear
135
Although the exact cause of Meniere’s Disease remains a mystery, which of the following could most reasonably be caused by a build up of excessive endolymph fluid?
A. Auditory canal becomes blocked
B. Hair cell function is altered
C. Stapes can no longer vibrate
D. Tympanic membrane is ruptured
B. Hair cell function is altered
136
Suppose the stereocilia of one hair cell become permanently bent. What will most likely happen as a consequence?
A. A single pitch will be constantly perceived
B. A single pitch will no longer be perceivable
C. A or B depending on the hair cell’s location
D. A or B depending on the bending’s direction
D. A or B depending on the bending’s direction
137
If a hair cell bends toward the kinocilium, K+ channels will open and the cell will \_\_\_\_\_\_\_\_\_.
A. Depolarize
B. Hyperpolarize
C. Stay at the same membrane potential
A. Depolarize
138
If a hair cell bends toward the kinocilium...
A. It generates action potentials
B. It releases neurotransmitters
C. Both A and B
D. Neither A nor B
B. It releases neurotransmitters
139
During an auditory hallucination, sound is perceived without an auditory stimulus. Based on what you learned about the brain last week, stimulation in which lobe of the brain would be most likely to generate an auditory hallucination?
A. Frontal lobe
B. Occipital lobe
C. Parietal lobe
D. Temporal lobe
D. Temporal lobe
140
Cutting the auditory nerve could treat the symptoms of:
A. Tinnitus (Meniere’s disease) only
B. Auditory hallucinations (epilepsy) only
C. Neither
D. Both
A. Tinnitus (Meniere’s disease) only
141
You wake up in the middle of the night. As you look around the dark room, your pupils ________ to let in ________ light.
A. Constrict; more
B. Constrict; less
C. Dilate; more
D. Dilate; less
C. Dilate; more
142
Rods and Cones hyperpolarize in response to light. Select A or B for the image that represents your rod cells in the dark.
A
143
True or False: You turn on a light so you can get a glass of water. BEFORE you turn on the light, the Effector Enzyme is activated.
False
144
You turn on a light so you can get a glass of water. At the moment the light turns ON, the concentration of cGMP inside your rods and cones \_\_\_\_\_\_\_\_.
A. Increases
B. Decreases
C. Does not change
B. Decreases
145
True or False: You turn on a light so you can get a glass of water. At the moment the light turns on, the Sodium (Na+) enters the cell.
False
146
You turn on a light so you can get a glass of water. At the moment the light turns ON, the amount of neurotransmitters released by your rods and cones \_\_\_\_\_\_\_\_.
A. Increases
B. Decreases
C. Does not change
B. Decreases
147
In the dark your rod cells are releasing neurotransmitter on to the bipolar cells. In the dark, your bipolar cells are \_\_\_\_\_\_\_\_\_.
A. Hyperpolarized
B. Depolarized
C. At resting membrane potential
A. Hyperpolarized
148
You turn on a light so you can get a glass of water. At the moment the light turns on, your bipolar cells will ______ firing action potentials.
A. Start
B. Stop
C. None of the above. (Bipolar cells do not fire Action potentials)
C. None of the above. (Bipolar cells do not fire Action potentials)
149
You turn on a light so you can get a glass of water. At the moment the light turns on, your bipolar cells will ______ retinal ganglion cells.
A. Excite
B. Inhibit
C. None of the above. (Bipolar cells do not communicate to retinal ganglion cells )
A. Excite
150
You turn on a light so you can get a glass of water. At the moment the light turns on, your retinal ganglion cells will \_\_\_\_\_firing action potentials.
A. Start
B. Stop
C. None of the above. (retinal ganglion cells do not fire action potentials)
A. Start
151
Black widow spider venom causes explosive release of ACh. At the site of a black widow spider bite, muscle membrane potential will \_\_\_\_\_\_\_\_\_\_.
A. Become more positive
B. Become more negative
C. Not change
A. Become more positive
152
Organophosphates inhibit the activity of the enzyme acetylcholinesterase (AChE). Exposure to organophosphates will therefore __________ muscle stimulation by motor neurons.
A. Increase
B. Decrease
C. Not change
A. Increase
153
Where does the cycle start?!? When a muscle is completely relaxed (no contraction is occurring), at which point is the cycle paused?
B
154
True or False: In a muscle affected by Botox, Ca2+ channels in the SR will be mostly open.
False
155
True or False: In a muscle affected by Botox, myosin will be primarily bound to ATP.
False, no calcium released from sarcoplasmic reticulum.
156
True or False: In a muscle affected by Botox, tropomyosin will be bound to actin.
True
157
True or False: In a muscle affected by Botox, the cell will become hyperpolarized.
False
158
You accidentally inoculate (infect) yourself with Clostridium tetani.
In the diagram shown here, which neuron will eventually contain tetanus toxin.
Use the labels (A-E) as answer choices.
C, affects the INHIBITORY interneuron
159
You accidentally inoculate (infect) yourself with Clostridium tetani.
In the diagram shown here, which nerve fiber
is no longer receives IPSPs.
Use the labels (A-E) as answer choices.
D
160
A competitive track star at UCLA is training for an upcoming meet. In the first 50 m of the 800 m race, which muscle fiber type is the runner using?
A. Fast-twitch muscle fibers
B. Slow-twitch muscle fibers
A. Fast-twitch muscle fibers
161
You are doing an experiment on a new class of G protein−coupled receptor. You make several cell lines that each express the receptor, the corresponding G protein, and adenylyl cyclase. Each cell line has different mutations in these components. You decide to measure cyclic AMP (cAMP) in the cells of each cell line to understand the effect of each of these mutations. Below is a list of mutations. For each, indicate whether the amount of cAMP in the cells will increase, decrease, or stay the same.
A mutation in the G protein−coupled receptor that prevents it from binding to the G protein. The amount of cAMP in cells will:
A. increase
B. stay the same
C. decrease
C. decrease
162
A mutation in the α unit of the G protein that prevents it from binding to adenylyl cyclase but not the receptor. The amount of cAMP in cells will:
A. increase
B. decrease
C. stay the same
B. decrease
163
A mutation in the α subunit of the G protein that prevents the release of bound GDP. The amount of cAMP in cells will:
A. decrease
B. stay the same
C. increase
A. decrease
164
A mutation in the α subunit of the G protein that prevents the release of bound GTP. The amount of cAMP in cells will:
A. increase
B. decrease
C. stay the same
A. increase
165
A mutation of the G protein−coupled receptor that removes the extracellular domain of the receptor. The amount of cAMP in cells will:
A. decrease
B. stay the same
C. increase
A. decrease
166
A mutation of the G protein−coupled receptor that allows it to bind the α subunit of the G protein in the absence of ligand. The amount of cAMP in cells will:
A. decrease
B. increase
C. stay the same
B. increase
167
Phosphatases are a family of enzymes that remove phosphate groups from specific proteins; these phosphate groups had been added to the proteins by protein kinases. Vanadate is an inhibitor of phosphatases in eukaryotic cells. What effect would vanadate have on the response of cells to signals received by receptor kinases?
A. The response of the cell would be shorter than it normally would.
B. The response of the cell would last longer than it normally would.
C. The signal would still bind the receptor, so there would be no effect.
B. The response of the cell would last longer than it normally would.
168
Many mutations in receptor kinases that lead to cancer allow the receptor to dimerize and become activated, even in the absence of signaling molecules. An example is a mutant form of the EGF receptor kinase called Her2/neu. An antibody that prevents dimerization of Her2/neu receptor kinases is being tested for its effectiveness in preventing cancer. At which stage does this drug work?
A. It prevents the termination of the signal.
B. It prevents the receptor from becoming activated.
C. It prevents the signaling cell from producing the signal.
D. It prevents the receptor from binding to the signal.
B. It prevents the receptor from becoming activated.
169
Suppose that frog embryos are genetically manipulated so that the epidermal cells expressed both E-cadherin and N-cadherin on their cell surface. The neuronal tissue and epidermal tissues are collected from the embryos and treated as illustrated in Figure 10.12b. Which of the following would you predict would happen now that N-cadherin is also present on the surface of the epidermal cells?
A. The genetically modified epidermal cells would adhere to each other and to neuronal cells.
B. The genetically modified epidermal cells would adhere to each other, and not to the neuronal cells, because they would still be epidermal cells regardless of the presence of an additional cell adhesion protein on their surface.
C. The genetically modified epidermal cells would adhere to neuronal cells and would no longer adhere to epidermal cells.
A. The genetically modified epidermal cells would adhere to each other and to neuronal cells.
Instructional Guidance: This question assesses understanding of cadherin function using an experimental example similar to the one described in the chapter.
170
In order for a tumor cell to metastasize, which of the following would you expect to happen?
A. an increase of cadherin expression and a decrease in integrin expression
B. an increase in both cadherin and integrin expression
C. a decrease in cadherin expression and an increase of integrin expression
D. a decrease in both cadherin and integrin expression
C. a decrease in cadherin expression and an increase of integrin expression
171
Aldosterone, in the figure below, is a hormone secreted by the adrenal cortex, and insulin is a peptide secreted by the pancreas. When aldosterone contacts a target cell, it binds to an intracellular receptor and migrates to the nucleus; insulin binds to extracellular receptors on the plasma membrane. What is the MOST likely reason for this difference?
A. Insulin is too large to interact chemically with DNA.
B. Aldosterone is hydrophilic and, therefore, must enter the aqueous environment of the cytoplasm to have an effect.
C. Aldosterone is too small to bind extracellular receptors on the plasma membrane.
D. Aldosterone is lipid-soluble and, therefore, easily crosses the phospholipid bilayer of the plasma membrane.
D. Aldosterone is lipid-soluble and, therefore, easily crosses the phospholipid bilayer of the plasma membrane.
172
Please study the table below.
Each pair of phrases in the same row shows a valid comparison between the anterior and posterior pituitary EXCEPT:
A.
D.
C.
B.
C.
Instructional Guidance: This question requires factual recall of adrenal–pituitary pathways.
173
Ligand-gated ion channels are found within the postsynaptic neuron's cell membrane. Why are ligand-gated ion channels critical to how synapses communicate information? (Select all that apply.)
A. Ligand-gated ion channels are found within a neuron's dendrites but not its axon.
B. Ligand-gated ion channels open more rapidly than voltage-gated ion channels.
C. Ligand-gated ion channels enable specific neurotransmitters released by presynaptic neurons to exert either excitatory or inhibitory effects on the postsynaptic cell.
D. Ligand-gated ion channels allow the postsynaptic cell to control, through intracellular signaling, to which neurotransmitters the postsynaptic cell responds.
A. Ligand-gated ion channels are found within a neuron's dendrites but not its axon.
C. Ligand-gated ion channels enable specific neurotransmitters released by presynaptic neurons to exert either excitatory or inhibitory effects on the postsynaptic cell.
174
Voltage-gated ion channels underlie the function of electrically excitable cells, such as nerve and muscle cells. Which of the following statements is TRUE about voltage-gated ion channels?
A. Voltage-gated ion channels vary in terms of how rapidly they respond to changes in membrane potential.
B. Voltage-gated ion channels involve a conformational change of the transmembrane protein in response to membrane voltage that changes the channel's permeability to ion flow through the channel.
C. All of these choices are correct.
D. Voltage-gated ion channels open and close in response to changes in membrane potential.
C. All of these choices are correct.
175
Imagine you genetically engineered a neuron to produce voltage-gated Na+ and K+ channels that opened at the same time in response to a change in voltage. How would that change the recording shown in the figure?
A. The period of hyperpolarization would be longer.
B. Threshold values would increase.
C. No action potential would be generated.
D. The peak voltage would be higher.
E. The peak would occur over a longer period of time.
C. No action potential would be generated.
176
The magnitude of the action potential is correlated with the strength of the stimulating input.
A. True
B. False
B. False
177
Which of the following is an example of the effector's role in maintaining homeostasis?
A. vasodilation on a cold winter day
B. decrease in body temperature on a cold day
C. increased body temperature during a workout
D. increased sweating on a hot summer day
D. increased sweating on a hot summer day
Instructional Guidance: This helps students evaluate different situations and determine the appropriate response. In doing so they can determine what the response of the effector is once stimulated by the hypothalamus.
178
Sometimes after falling backward and hitting their heads, people may say that they are “seeing stars.” Which area of the brain was affected?
A. parietal lobe
B. cerebellum
C. occipital lobe
D. frontal lobe
C. occipital lobe
179
After suffering a stroke, a patient may be unable to speak. The stroke has affected the _____ of the brain.
A. occipital lobe
B. parietal lobe
C. frontal lobe
D. cerebellum
C. frontal lobe
180
How can the cells within your body become different cell types? (Select all that apply.)
A. Cells differentiate as they divide by mitosis.
B. The cells are in different local environments.
C. The cells have different genes.
D. The cells' genes are regulated.
B. The cells are in different local environments.
D. The cells' genes are regulated.
181
Zebrafish embryos change the color of the melanophore cells in their skin to a darker shade by:
A. dynein motor proteins moving pigment granules outward from the center of the cell.
B. kinesin motor proteins moving pigment granules outward from the center of the cell.
C. kinesin motor proteins moving pigment granules inward toward the center of the cell.
D. dynein motor proteins moving pigment granules inward toward the plus end of microtubules.
E. dynein motor proteins moving pigment granules inward toward the center of the cell.
B. kinesin motor proteins moving pigment granules outward from the center of the cell.
182
Which one of the following properly groups a cell junction with a cytoskeletal element and a cell adhesion molecule?
A. desmosome, intermediate filament, cadherin
B. hemidesmosome, microfilament, cadherin
C. adherens junction, microfilament, integrin
D. hemidesmosome, intermediate filament, cadherin
A. desmosome, intermediate filament, cadherin
183
Which of the following is NOT an essential element involved in communication between all cells?
A. second messenger
B. responding cell
C. receptor protein
D. signaling molecule
A. second messenger
184
During the signal transduction process, the signal often triggers a signal transduction cascade. For example, an activated receptor activates hundreds of protein A. Each activated protein A activates hundreds of protein B and so on until a cellular response occurs. What purpose does this cascade serve?
A. The cascade makes signaling easier to shut off or terminate.
B. Having several intermediates allows for greater control of the response.
C. Having a cascade allows the cell to respond to different signals.
D. The cascade serves to amplify the signal, so one activated receptor can have a significant response.
D. The cascade serves to amplify the signal, so one activated receptor can have a significant response.
185
Shown here are four ligands (M, H, K, and L) and their corresponding receptors along with three genes (U, V, and W) whose activity the receptor controls through signal transduction. The arrows indicate gene activation, the T-bars indicate gene repression.
If both U and V are required to activate W, which ligand (or ligands) result in W being active?
A. ligand K
B. None of the answer options is correct.
C. ligand H
D. ligand L
E. ligand M
E. ligand M
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