Exam 1 Bio360 ASU-Animal Phys
Based on the "Cool mice live longer" article, which of the following body temperatures might lead to a longer life? 36.5 degrees Celsius 37.0 degrees Celsius 37.5 degrees Celsius
36.5 degrees Celsius
Which of the following is an example of an organism being in homeostasis? Select all the correct answers. There may be more than one true statement (3 pts) Part A A mouse with a fever that has an elevated core body temperature that is equal to its hypothalamic setpoint temperature An ASU student sweating on the way to class because her core body temperature is higher than her setpoint temperature A child experiencing a fever seizure that is sweating because his core body temperature is higher than its setpoint temperature A dog shivering in cold weather to increase body temperature, but that currently has a core body temperature that is lower than the setpoint temperature A hoary marmot in torpor that has a decreased core body temperature that is equal to its decreased hypothalamic setpoint temperature A rabbit with a fever that is shivering because its core body temperature is lower than its setpoint temperature
A mouse with a fever that has an elevated core body temperature that is equal to its hypothalamic setpoint temperature A hoary marmot in torpor that has a decreased core body temperature that is equal to its decreased hypothalamic setpoint temperature
What is the main difference between the concepts of "steady-state" and "equilibrium?" A steady-state system is dynamic, whereas a system in equilibrium is not. A system in equilibrium is also in homeostasis, whereas a steady-state system can never be homeostatic. There is no movement of materials within a steady-state system, but materials move freely in an equilibrium. Steady-state systems are inherently unstable and will eventually collapse while systems in equilibrium are stable.
A steady-state system is dynamic, whereas a system in equilibrium is not.
Which event causes cross bridge detachment? nervous input ends release of ADP and inorganic phosphate from the myosin head release of calcium from troponin ATP binding to the myosin head
ATP binding to the myosin head
How/when does the myosin head cock back to store energy for the next cycle? The power stroke cocks the myosin head. when ADP is released from the myosin head After the myosin head detaches, energy from ATP hydrolysis is used to re-cock the myosin head. The sliding of the actin myofilament during the power stroke re-cocks myosin heads that have previously delivered their power stroke.
After the myosin head detaches, energy from ATP hydrolysis is used to re-cock the myosin head.
Based on the "Cool mice live longer" article, what might be ways to live longer? Not eat as much Cool our body temperatures down 0.5 degrees Celsius Not produce as many free radicals All of the above
All of the above
Brown fat is found in infants. functions in nonshivering thermogenesis. is innervated by the sympathetic nervous system. contains a rich vascular supply. All of these answers are correct.
All of these answers are correct.
What is the trigger for ACh release into the synaptic cleft of a neuromuscular junction? An action potential at the axon terminal opens voltage-gated Ca2+ channels. Contraction of nearby muscle cells stimulates the release of ACh from surrounding neurons of the same motor unit. Acetylcholinesterase opens vesicles, allowing ACh to diffuse into the cleft. Stimulation of the presynaptic membrane releases ACh via a cAMP second messenger system.
An action potential at the axon terminal opens voltage-gated Ca2+ channels.
What happens if a graded stimulus is of sufficient strength to reach threshold at the trigger zone? The graded stimulus moves through the cell more quickly. The cell becomes more permeable to Cl-. An action potential occurs. The membrane is hyperpolarized.
An action potential occurs.
Skeletal muscle moves a bone at a joint, such as flexing the forearm at the elbow. How is the opposite action produced (i.e., extension at the elbow)? The muscle that produces flexion extends to produce extension. An antagonistic muscle produces the opposite movement. An antagonistic neuron secretes a different neurotransmitter onto the same muscle to produce the opposite skeletal movement. The muscle that produces flexion relaxes to produce extension.
An antagonistic muscle produces the opposite movement.
Which two properties determine the conduction velocity in a mammalian neuron? The voltage-gated K+ ion channel concentration and axon diameter. The leak resistance of the membrane and myelination Axon diameter and the leak resistance of the membrane Myelination and voltage-gated Na+ channel concentration
Axon diameter and the leak resistance of the membrane
Bats use their TRPV1 receptors to detect the warmth of blood in their prey. Given that finding, which of the following mutations would be evolutionarily advantageous for the prey (but not the bat)? Note: there may be more than one correct answer. Bats that had a mutation in their TRPV1 receptors so that the bats can't sense capsaicin (the active ingredient in chili peppers), but could still sense temperature Prey that had a mutation in their TRPV1 receptors so that the prey can't sense temperature Prey that had a mutation in their TRPV1 receptors so that the prey can't sense capsaicin (the active ingredient in chili peppers), but could still sense temperature Bats that had a mutation in their TRPV1 receptors so that the temperature threshold for receptor activation is 10 degrees higher than normal Prey that had a blood temperature that was 1 degree lower than the threshold temperature of the bat's TRPV1 receptors Bats that had a mutation in their TRPV1 receptors so that the bats can't sense temperature
Bats that had a mutation in their TRPV1 receptors so that the temperature threshold for receptor activation is 10 degrees higher than normal Prey that had a blood temperature that was 1 degree lower than the threshold temperature of the bat's TRPV1 receptors Bats that had a mutation in their TRPV1 receptors so that the bats can't sense temperature
Sarin nerve gases block acetylcholinesterase, an enzyme that breaks down acetylcholine. People exposed to sarin nerve gases have convulsions and muscle twitches due to too much muscle contraction. Which of the following are possible treatments for symptoms at the neuromuscular junction following exposure to sarin nerve gases? Select all the correct answers. There may be more than one true statement. Part A Block acetylcholine signaling with monoclonal antibodies specific to acetylcholine receptors Decrease the release of acetylcholine from pre-synaptic terminal Decrease the number of acetylcholine receptors on post-synaptic terminal Treat patients with physostigmine to block acetylcholinesterase Increase the number of acetylcholine molecules in the synapse Treat patients with acetylcholine receptor antagonists that bind to acetylcholine receptors at the neuromuscular junction
Block acetylcholine signaling with monoclonal antibodies specific to acetylcholine receptors Decrease the release of acetylcholine from pre-synaptic terminal Decrease the number of acetylcholine receptors on post-synaptic terminal Treat patients with acetylcholine receptor antagonists that bind to acetylcholine receptors at the neuromuscular junction
What is the role of calcium in the cross bridge cycle? Calcium binds to myosin, causing the myosin head to release from the actin myofilament. Calcium binds to troponin, altering its shape. Calcium binds to active sites on actin, forming the cross bridge. Calcium binds to troponin, exposing the active site on troponin.
Calcium binds to troponin, altering its shape.
Define an action potential
Rapid and uniform electrical signal conducted down a cell membrane.
Torpor is a regulated lowering of the setpoint in the hypothalamus. Which of the following would be the best way for a bear to regain homeostasis after the setpoint in the hypothalamus is lowered? Note: only one correct answer Non-shivering thermogenesis Induce a higher metabolic rate Shivering Induce a lower metabolic rate Increase blood flow to the skin
Induce a lower metabolic rate
Where do most action potentials originate? Nodes of Ranvier Axon terminal Cell body Initial segment
Initial segment
Based on the "Cool mice live longer" article, how did the researchers make heat in the brain? Put the mice in a hot room to warm up their body temperature Inserted a gene called "uncoupling protein 2" that led to heat being made in an area of the brain called the hypothalamus Inserted a hot piece of metal into the brains of the mice
Inserted a gene called "uncoupling protein 2" that led to heat being made in an area of the brain called the hypothalamus
How would the absolute refractory period be affected if voltage-gated sodium channels remained inactivated? There is only ONE correct answer. Part A It would be shorter than normal It would be the same whether the channels remained inactivated or not It would be longer than normal
It would be longer than normal
How would the absolute refractory period be affected if voltage-gated sodium channels remained inactivated? It would be longer than normal. It would be the same whether the channels remained inactivated or not. It would be shorter than normal. None of the answers are correct.
It would be longer than normal.
If you blocked IL-1 from binding to its receptor by administering an IL-1 monoclonal antibody, which of the following would be true? Select all the correct answers. There may be more than one true statement (4 pts) Part A It would likely result in an elevated setpoint temperature in the hypothalamus It would likely result in taking a few days longer to fight off pathogens than if IL-1 had not been blocked from binding to its receptor It would likely result in decreased symptoms in patients with periodic fever syndromes It would likely result in fewer prostaglandin E2 (PGE2) molecules being made It would likely result in more frequent fever seizures in people who had previously had a fever seizure It would likely result in more LPS being made by the body It would likely result in an elevated core body temperature It would likely result in less COX-2 being made
It would likely result in taking a few days longer to fight off pathogens than if IL-1 had not been blocked from binding to its receptor It would likely result in decreased symptoms in patients with periodic fever syndromes It would likely result in fewer prostaglandin E2 (PGE2) molecules being made It would likely result in less COX-2 being made
Sodium and potassium ions can diffuse across the plasma membranes of all cells because of the presence of what type of channel? Sodium-potassium ATPases Ligand-gated channels Voltage-gated channels Leak channels
Leak channels
Why is the resting membrane potential (Vm) approximately - 70 mV for most cells? Most membranes are 40 times more permeable to K+ than to Na+. Most cells contain a large concentration of Cl- making them negatively charged. The large concentration of proteins in the interstitial space draws Na+ out of the cell making it negatively charged. Most membranes are 10 times more permeable to Na+ than to K+.
Most membranes are 40 times more permeable to K+ than to Na+.
Tysabri is a treatment for multiple sclerosis. It is a monoclonal antibody that blocks immune cells from getting through the blood brain barrier. If a patient with multiple sclerosis is treated with tysabri, given the mechanism of tysabri, which of the following is possible? Select all the correct answers. There may be more than one true statement. Multiple sclerosis symptoms decrease Fewer immune cells get into the brain Myelinated neurons rearrange voltage-gated Na+ channels so they can regenerate action potentials more often Patient dies from an opportunistic infection caused by a virus Multiple sclerosis symptoms do not decrease More immune cells get into the brain
Multiple sclerosis symptoms decrease Fewer immune cells get into the brain Patient dies from an opportunistic infection caused by a virus Multiple sclerosis symptoms do not decrease
Which of the following is the most likely mechanism to explain the fact that birds cannot sense capsaicin? There is only ONE correct answer. (1pt) Mutated TRPA1 receptors in birds that result in more positive ions than normal coming into the cell Mutated TRPV1 receptors in birds that result in more positive ions than normal coming into the cell Mutated TRPA1 receptors in birds that result in fewer positive ions than normal coming into the cell Mutated capsaicin that binds to TRPV1 receptors in birds and prevents normal capsaicin from binding Mutated capsaicin that cannot bind to TRPV1 receptors in birds Mutated TRPV1 receptors in birds that result in fewer positive ions coming into the cell
Mutated TRPV1 receptors in birds that result in fewer positive ions coming into the cell
Which is the smallest structure? Muscle fiber Myofibril Myofilament Myosin
Myosin
BMD (2,3-butanedione 2-monoximime) inhibits myosin, such that ATP can bind to myosin but myosin is unable to hydrolyze the bound ATP. What effect would BMD have on the cross bridge cycle? Myosin heads would remain attached to actin, unable to perform the power stroke. Tropomyosin would not move, and the active sites on actin would not be exposed. Myosin heads would remain attached to actin, unable to detach. Myosin heads would remain detached, unable to cock.
Myosin heads would remain detached, unable to cock.
Which structural protein of skeletal muscle also acts as an enzyme? Na+/K+ ATPase Actin filaments Myosin heavy chains Tropomyosin
Myosin heavy chains
What would be the effect of ACh binding to its receptor on the postsynaptic muscle cell? Ca2+ would leak out of the cell as Na+ flowed into the cell. Only Na+ would flow into the cell. Ca2+ would flow into the cell as Na+ flowed out of the cell. Na+ would flow into the cell and K+ would flow out of the cell.
Na+ would flow into the cell and K+ would flow out of the cell.
What prevents the Na+ and K+ gradients from dissipating? Na+ and K+ leaks Na+ cotransporter Na+-K+ ATPase H+-K+ ATPase
Na+-K+ ATPase
what's similar and different about neurons synapsing on to other neurons compared to neurons synapsing on to muscle cells?
Neuron to neuron communication between the synapses are simpler than cell to cell communication between synapses in that the ion channels are the only method of communication that is occurring. cell-to cell communication uses chemicals as well as electrical signalling in order to coordinate function and maintain homeostasis. In cell-to cell communication, neurotransmitters are used in cell-to cell communication as well Ca++which is used to trigger exocytosis of synaptic vesicle contents.
What characterizes repolarization, the second phase of the action potential? Once the membrane depolarizes to a threshold value of approximately -55 mV, it repolarizes to its resting value of -70 mV. As the membrane repolarizes to a negative value, it goes beyond the resting state to a value of -80 mV. Once the membrane depolarizes to a peak value of +30 mV, it repolarizes to its negative resting value of -70 mV. Before the membrane has a chance to reach a positive voltage, it repolarizes to its negative resting value of approximately -70 mV.
Once the membrane depolarizes to a peak value of +30 mV, it repolarizes to its negative resting value of -70 mV.
Choose the correct example of signal amplification. A chemical signal is converted into a mechanical signal. An electrical signal is converted into a mechanical signal. One hormone-producing cell alters the activity of more than one target cell. One hormone molecule causes the activation of more than one second messenger molecule.
One hormone molecule causes the activation of more than one second messenger molecule.
Which of the following is the largest level of organization? Atoms Tissues Organs Molecules
Organs
For dogs, which are endotherms, what is most likely to cause the hypothalamic setpoint to change within a short period of time? There is only ONE correct answer. Non-shivering thermogenesis in brown adipose tissue Shivering thermogenesis in muscles Sensory neurons that sense cool environmental temperatures Environmental temperatures that are warmer than the core body temperature Release of pyrogens from cells in the body
Release of pyrogens from cells in the body
Ions are unequally distributed across the plasma membrane of all cells. This ion distribution creates an electrical potential difference across the membrane. What is the name given to this potential difference? Threshold potential Resting membrane potential (RMP) Positive membrane potential Action potential
Resting membrane potential (RMP)
According to the author of the article "The importance of stupidity in scientific research," which of the following would lead to more scientific discoveries? Scientists becoming more comfortable with being stupid Scientists taking fewer risks in their research projects Scientists getting the right answer for their experiments the first time they did them Scientists only working on projects that they understand fully
Scientists becoming more comfortable with being stupid
The binding of a single ligand to its receptor can activate many second messengers. Which characteristic of signal transduction systems is this? Signal conversion Signal amplification Signal specificity Signal initiation
Signal amplification
According to the article "The importance of stupidity in scientific research," which of the following best describes absolute stupidity? Bright people who might be working in areas that don't match their talents Other students in the class actually read the material, think about it and ace the exam, whereas you don't Not being intelligent enough to study science Stupidity that is inherent in our efforts to push our way into the unknown
Stupidity that is inherent in our efforts to push our way into the unknown
According to the "Feel the burn" article, which of the following is true? Note: there can be more than one correct answer. TRP channels are located on neurons Some TRP channels can be activated by specific temperatures TRP channels are proteins TRP channels are cation channels that allow calcium to come into the cell Members of the family of TRP channels can be activated by molecules such as menthol, spearmint, mustard, cinnamon, or garlic.
TRP channels are located on neurons Some TRP channels can be activated by specific temperatures TRP channels are proteins TRP channels are cation channels that allow calcium to come into the cell Members of the family of TRP channels can be activated by molecules such as menthol, spearmint, mustard, cinnamon, or garlic.
Which of the following would you predict to happen immediately if you took an Emperor penguin from Antarctica and tried to keep it as a pet in your backyard in Phoenix in 115 degree weather. There may be more than one correct answer. That emperor penguin would experience hyperthermia That emperor penguin would experience hypothermia That emperor penguin would mutate to decrease its insulation That emperor penguin's TRPV1 receptors in sensory neurons would sense heat That emperor penguin's hypothalamic setpoint temperature would decrease That emperor penguin would evolve a lower core body temperature
That emperor penguin would experience hyperthermia That emperor penguin's TRPV1 receptors in sensory neurons would sense heat
Definition of homeostasis.
The ability of an organism to maintain relatively constant internal conditions despite variability in external conditions.
What is the best definition for "homeostasis?" The environment inside a cell, regulated by proteins and ions, with the ability to produce energy. The ability of living systems to maintain a relatively constant internal environment. The chemical reactions that maintain life The ability of a system to return to an unstretched state.
The ability of living systems to maintain a relatively constant internal environment.
What role does tropomyosin play in the cross bridge cycle? Tropomyosin binds to calcium, causing muscle relaxation. The displacement of tropomyosin exposes the active sites of actin, allowing cross bridges to form. Tropomyosin pushes the myosin head away, causing cross bridge detachment. Tropomyosin moves the actin filament relative to the myosin filament.
The displacement of tropomyosin exposes the active sites of actin, allowing cross bridges to form.
If I decrease the extracellular conc. of Na+ example: 150 to 50 But the Intracellular conc Remains the same, How does the manipulation affect the equilibrium potential of Na+? The equilibrium potential of Na+ is now the same as before we manipulated the extracellular Na+ concentration The equilibrium potential of Na+ is now lower (more negative) The equilibrium potential of Na+ is now greater (more positive)
The equilibrium potential of Na+ is now lower (more negative)
On average, the resting membrane potential is -70 mV. What does the sign and magnitude of this value tell you? The outside surface of the plasma membrane is much more negatively charged than the inside surface. There is no electrical potential difference between the inside and the outside surfaces of the plasma membrane. The inside surface of the plasma membrane is much more positively charged than the inside surface. The inside surface of the plasma membrane is much more negatively charged than the outside surface.
The inside surface of the plasma membrane is much more negatively charged than the outside surface.
Which is the best example of integration in physiology? The association of fond memories with the smells of a favorite meal The interaction of nervous and endocrine signals to regulate blood flow to the small intestines The immune system responding to bacteria multiplying in the submucosal layer of the skin Air is carried into alveoli in the lungs where oxygen can diffuse through the respiratory membrane into the blood.
The interaction of nervous and endocrine signals to regulate blood flow to the small intestines
What are the thermal adaptations of Jack rabbits found in the Sonoran desert Lepus californicus?
The large ears of this hare help it to lose heat and thereby cooling its body temperature. They can adjust the amount of blood that flows through their ears in order to control their body heat on the hot desert days.
Why is an action potential conducted in only one direction, from an axon hillock to an axon terminal? The membrane channels upstream are refractory and cannot open. The number of voltage-gated ion channels increases along the length of the axon. The channels are progressively easier to open down the length of the axon. Second messengers activate channels sequentially.
The membrane channels upstream are refractory and cannot open.
What characterizes depolarization, the first phase of the action potential? The membrane potential changes from a negative value to a positive value. The membrane potential changes to a much more negative value. The membrane potential changes to a less negative (but not a positive) value. The membrane potential reaches a threshold value and returns to the resting state.
The membrane potential changes from a negative value to a positive value.
What happens to the resting membrane potential when the axonal membrane suddenly becomes 20 times more permeable to sodium than to potassium? Use the Goldman-Hodgkins-Katz equation to justify your answer. The membrane potential decreases (more negative) The membrane potential stays the same The membrane potential increases (more positive)
The membrane potential increases (more positive)
What event triggers the generation of an action potential? The membrane potential must depolarize from the resting voltage of -70 mV to a threshold value of -55 mV. The membrane potential must return to its resting value of -70 mV from the hyperpolarized value of -80 mV. The membrane potential must hyperpolarize from the resting voltage of -70 mV to the more negative value of -80 mV. The membrane potential must depolarize from the resting voltage of -70 mV to its peak value of +30 mV.
The membrane potential must depolarize from the resting voltage of -70 mV to a threshold value of -55 mV.
According to the "Feel the burn" article, what happened in mice that had the TRPV1 channel "knocked out" (genetically removed)? Note: there could be more than one correct answer. The mice were unable to sense cold temperatures The mice were unable to sense hot temperatures The mice had lower than normal responses to hot temperatures, but still responded to hot temperatures The mice had lower than normal responses to capsacin (the active ingredient in chili peppers), but still responded to capsacin The mice were unable to sense capsacin (the active ingredient in chili peppers)
The mice had lower than normal responses to hot temperatures, but still responded to hot temperatures The mice were unable to sense capsacin (the active ingredient in chili peppers)
If myelin were added to a neuron that was normally unmyelinated, which of the following is most likely given your understanding of how myelin influences conduction speeds? There is only ONE correct answer. Part A The neuron would signal slower to the next neuron The neuron would signal at the same speed to the next neuron The neuron would signal faster to the next neuron
The neuron would signal faster to the next neuron
The resting membrane potential depends on two factors that influence the magnitude and direction of Na+ and K+ diffusion across the plasma membrane. Identify these two factors. The presence of concentration gradients and Na+-K+ pumps The presence of concentration gradients and leak channels The presence of a resting membrane potential and leak channels The presence of concentration gradients and voltage-gated channels
The presence of concentration gradients and leak channels
What determines whether or not a particular cell will respond to a particular hormone? The target cell must have access to the bloodstream. The target cell must lack enzymes that can destroy the hormone. The target cell must be near the source of the hormone. The target cell must have a receptor that specifically binds to that hormone
The target cell must have a receptor that specifically binds to that hormone
During contraction, what prevents actin myofilaments from sliding backward when a myosin head releases? There are always some myosin heads attached to the actin myofilament when other myosin heads are detaching. The cross bridge remains in place, preventing the actin myofilament from sliding. The actin myofilament can only move in one direction relative to the myosin filament. Calcium blocks the active sites on actin.
There are always some myosin heads attached to the actin myofilament when other myosin heads are detaching.
The plasma membrane is much more permeable to K+ than to Na+. Why? There are many more voltage-gated K+ channels than voltage-gated Na+ channels. Ligand-gated cation channels favor a greater influx of Na+ than K+. The Na+-K+ pumps transport more K+ into cells than Na+ out of cells. There are many more K+ leak channels than Na+ leak channels in the plasma membrane.
There are many more K+ leak channels than Na+ leak channels in the plasma membrane.
What are the thermal adaptations of the flat bark beetle Cucujus clavipes puniceus?
These beetles survive extremely cold weather by producing an antifreeze protein that binds to sites where ice would form in the winter, producing glycerol that drives the freezing point down, and by losing water in their bodies before winter so they don't freeze.
What are the thermal adaptations of the Alaskan Upis beetle Upis ceramboides?
These beetles survive extremely cold weather by using a biological anti-freeze or a chemical called xylomannan.
What are the thermal adaptations of Artic hares Lepus arcticus?
These hares have thicker fur coats and have a low surface area to volume ratio to conserve body heat. A feature that is evident of this is their shortened ears.They sometimes dig shelters in snow and huddle together to share warmth.
What are the thermal adaptations of African penguins Spheniscus demersus?
These penguins have thick fat layers for insulation and orientate themselves with their backs to the sun so that their feet, flippers and oral surfaces are shaded, thereby facilitating radiation and convective heat loss. Physiological responses to heat stress include panting (evaporative cooling) and moderate hyperthermia.
What are the thermal adaptations of Emperor penguins Aptenodytes forsteri?
These penguins use a lot of feathers for insulation, with around 100 feathers per square inch on their bodies.. These penguins also have a layer of sub-dermal fat that can impede their mobility. An extra layer of insulation is formed by separate shafts of downy filaments between feathers and skin. These penguins are able to maintain their core body temperature without altering their metabolism over a wide range of temperatures.
According to the video "How simple ideas lead to scientific discoveries," the scientists he described in the video changed the world because of which of the following reasons. They had better educational backgrounds than the average person They were more curious than the average person They were born smarter than the average person They were from wealthier families than the average person
They were more curious than the average person
How does troponin facilitate cross bridge formation? Troponin controls the position of tropomyosin on the thin filament, enabling myosin heads to bind to the active sites on actin. Troponin moves away from the active sites on actin, permitting cross bridge formation. Troponin gathers excess calcium that might otherwise block actin's progress. Troponin hydrolyzes ATP, which provides the energy necessary for cross bridges to form.
Troponin controls the position of tropomyosin on the thin filament, enabling myosin heads to bind to the active sites on actin.
According to the NPR podcast about vampire bats, which of the following is true? Vampire bats use TRP receptors (which are also called TRP channels) to detect heat - to find the warmer patch of skin that has more blood vessels Vampire bats use TRP receptors (which are also called TRP channels) to detect predators that they need to avoid Vampire bats use TRP receptors (which are also called TRP channels) to detect moving prey
Vampire bats use TRP receptors (which are also called TRP channels) to detect heat - to find the warmer patch of skin that has more blood vessels
According to the article about tarantula venom, which of the following is true? Note: there could be more than one correct answer Venom from tarantulas activate the same neurons that sense the "hot" ingredient in chili peppers, capsaicin Venom from tarantulas activate a different receptor than the receptor that senses the "hot" ingredient in chili peppers, capsaicin Venom from tarantulas activate different neurons than those neurons that sense the "hot" ingredient in chili peppers, capsaicin Venom from tarantulas activate the same receptor that senses the "hot" ingredient in chili peppers, capsaicin
Venom from tarantulas activate the same neurons that sense the "hot" ingredient in chili peppers, capsaicin Venom from tarantulas activate the same receptor that senses the "hot" ingredient in chili peppers, capsaicin
What opens first in response to a threshold stimulus? Voltage-gated Na+ channels Ligand-gated Cl- channels Ligand-gated cation channels Voltage-gated K+ channels
Voltage-gated Na+ channels
What is the first change to occur in response to a threshold stimulus? Voltage-gated Na+ channels change shape, and their activation gates open. Voltage-gated Na+ channels change shape, and their inactivation gates close. Voltage-gated K+ channels change shape, and their activation gates open. Voltage-gated Ca2+ channels change shape, and their activation gates open.
Voltage-gated Na+ channels change shape, and their activation gates open.
During the hyperpolarization phase of the action potential, the membrane potential drops lower (more negative) than resting membrane potential. From what you now know after completing the first two questions, what can you predict about the permeability of the axon during hyperpolarization? When compared to the axon at rest, the axon during hyperpolarization is more permeable to sodium than to potassium When compared to the axon at rest, the axon during hyperpolarization has the same permeability to sodium and potassium When compared to the axon at rest, the axon during hyperpolarization is more permeable to potassium than to sodium
When compared to the axon at rest, the axon during hyperpolarization is more permeable to potassium than to sodium
uring the hyperpolarization phase of the action potential, the membrane potential drops lower (more negative) than resting membrane potential. From what you now know after completing the first two questions, what can you predict about the permeability of the axon during hyperpolarization? When compared to the axon at rest, the axon during hyperpolarization is more permeable to sodium than to potassium When compared to the axon at rest, the axon during hyperpolarization has the same permeability to sodium and potassium When compared to the axon at rest, the axon during hyperpolarization is more permeable to potassium than to sodium
When compared to the axon at rest, the axon during hyperpolarization is more permeable to potassium than to sodium
When thinking about a physiological process from an evolutionary perspective, which of the following is NOT a consideration. There is only ONE correct answer. Part A Whether the physiological process affects a female organism's survival during the time in her life when she is able to have offspring Whether the physiological process affects a female organism's survival after she is no longer able to have children Whether there are selective pressures from the environment that affect the physiological process Whether the physiological process affects the female organism's reproductive fitness
Whether the physiological process affects a female organism's survival after she is no longer able to have children
Ion concentrations are first significantly affected after ________ action potential(s). one a few hundred a few dozen a few thousand a few million
a few thousand
The time during which an excitable membrane cannot respond to further stimulation regardless of the stimulus strength is the resting membrane potential. absolute refractory period. barrier period. relative refractory period.
absolute refractory period.
The all-or-none principle states that all stimuli great enough to bring the membrane to threshold will produce action potentials of identical magnitude. only sensory stimuli can activate action potentials. only motor stimuli can activate action potentials. the greater the magnitude of the stimuli, the greater the intensity of the action potential. all stimuli will produce identical action potentials.
all stimuli great enough to bring the membrane to threshold will produce action potentials of identical magnitude.
The classic steps for identifying an endocrine gland include removing the suspected gland, replacing the hormone, and which other step? blocking the hormone receptor imaging the suspected area blocking hormone action creating a state of hormone excess
creating a state of hormone excess
Increasing the amount of myelination _______. increases the time between action potentials increases the time between action potentials only for small-diameter axons decreases the time between action potentials has no effect on the time between action potentials
decreases the time between action potentials
The part of the neuron that receives most of the incoming signals is the __________. axon soma cell body dendrite
dendrite
Where in the cross bridge cycle does ATP hydrolysis occur? during the cocking of the myosin head during the removal of calcium from troponin during the movement of tropomyosin to expose the active sites on actin during the power stroke
during the cocking of the myosin head
Processes that cannot be predicted simply from understanding the functions of the individual components of the system are known as ________ properties. gradient emergent retrospective variable
emergent
The absolute refractory period of an action potential ensures one-way travel down an axon and allows a neuron to ignore a second signal sent that closely follows the first. only allows a neuron to ignore a second signal sent that closely follows the first. only ensures one-way travel down an axon. only prevents summation of action potentials. ensures one-way travel down an axon, allows a neuron to ignore a second signal sent that closely follows the first, and prevents summation of action potentials.
ensures one-way travel down an axon, allows a neuron to ignore a second signal sent that closely follows the first, and prevents summation of action potentials.
Voltage-regulated channels are located in the membranes of axons only. in the membranes of dendrites only. within the cytosol only. in the membranes of dendrites, in the membranes of axons, and on the neuron cell body. on the neuron cell body only.
in the membranes of dendrites, in the membranes of axons, and on the neuron cell body.
Cells regulate their level of activity by regulating the amount of proteins present in the cell at any given time, so an up regulation of enzymes would be expected to decrease the rate of reactions catalyzed by the enzymes. have no effect on the rate of reactions catalyzed by the enzymes. decrease the level of productivity of chemical reactions that rely on them. increase the cell's response that is produced by the reaction catalyzed by the enzyme. both decrease the level of productivity of chemical reactions that rely on them and decrease the rate of reactions catalyzed by the enzymes.
increase the cell's response that is produced by the reaction catalyzed by the enzyme.
The most rapid intracellular responses to signals result from activation of receptors that are also __________. ion channels second messengers enzymes amplifiers
ion channels
When neurotransmitter molecules bind to receptors in the plasma membrane of the receiving neuron, the receiving neuron becomes more positive inside. ion channels in the plasma membrane of the receiving neuron open. ion channels in the plasma membrane of the sending neuron open. vesicles in the synaptic terminal fuse to the plasma membrane of the sending neuron. the receiving neuron becomes more negative inside.
ion channels in the plasma membrane of the receiving neuron open.
A stronger stimulus to a neuron results in ________. greater frequency of graded potentials and larger voltage changes in the action potentials produced in response larger voltage changes in both graded and action potentials larger voltage changes in graded potentials and greater frequency of action potentials produced in response larger voltage changes in the graded potentials, but no changes in action potentials
larger voltage changes in graded potentials and greater frequency of action potentials produced in response
Cell membranes are mainly constructed from ________. lipids and carbohydrates nucleic acid and proteins carbohydrates and proteins lipids and proteins
lipids and proteins
Because of their shape, muscle cells are also known as ________. tubules muscle fibers fascicles myofibrils
muscle fibers
Thick filaments are composed of ________. actin myosin titin nebulin
myosin
What, specifically, is a cross bridge? myosin binding to actin tropomyosin covering the active sites on actin calcium binding to troponin ATP binding to the myosin head
myosin binding to actin
Compared to the outside surface, the inside of a resting cell membrane is positively charged. continuously reversing its electrical charge. electrically neutral. positively charged whenever the sodium-potassium pump is active. negatively charged.
negatively charged.
A molecule that carries information across a synaptic cleft is a receiving neuron. synapse. synaptic cleft. neurotransmitter. sending neuron.
neurotransmitter.
As the charge on the membrane of a typical neuron approaches 0 from -70 mV, the cell is only repolarizing. only hyperpolarizing. hyperpolarizing and becoming more difficult to stimulate only becoming more difficult to stimulate. only depolarizing.
only depolarizing.
A given hormone affects ________. all cells in the body, because hormones are secreted into blood, which is then transported everywhere only specific target cells, because hormones are delivered only to those cells only specific target cells, because nontarget cells lack the appropriate receptors all cells in the body, but different types of cells produce different responses to the hormone
only specific target cells, because nontarget cells lack the appropriate receptors
Nociceptors are responsible for the perception of itch only. pain and skin stretch. skin stretch only. pain only. pain and itch.
pain and itch.
Oxytocin is a hormone that is released in response to cervical dilation. It in turn causes more uterine contractions that will further dilate the cervix. What type of feedback loop does oxytocin trigger? positive feedback nociceptive feedback negative feedback local control
positive feedback
Which of the following is NOT a function of membrane proteins? anchor or stabilize the cell membrane bind to ligands act as transport molecules for various solutes produce energy regulate the passage of ions
produce energy
Most skeletal muscles move bones. They do this by _____ on the bone, to _____ the joint angle. pushing; increase or decrease pulling; decrease pushing; increase pulling; increase or decrease
pulling; increase or decrease
Chemicals known as ________ are fever-producing cytokines that are part of the normal immune response. adipocytokines free radicals ketone bodies pyrogens
pyrogens
Homeothermic refers to regulating body temperature within a narrow range. warm relationships with others of the same gender. shivering. natural treatments or remedies.
regulating body temperature within a narrow range.
The period of time during which an excitable membrane can respond again, but only if the stimulus is greater than the initial stimulus is the resting membrane potential. relative refractory period. absolute refractory period. excessive period.
relative refractory period.
Which of the following is NOT involved in creating the resting potential of a neuron? diffusion of sodium ions into the cell diffusion of potassium ions out of the cell resting membrane permeability for sodium ions greater than potassium ions resting membrane permeability for potassium ions greater than sodium ions
resting membrane permeability for sodium ions greater than potassium ions
The production of heat from rhythmic tremors of skeletal muscle is referred to as ________ thermogenesis. conductive diet-induced shivering convective
shivering
Each of the following is a function of proteins except one. Identify the exception. transport storage of genetic information catalyst carrying of messages support and structure
storage of genetic information
Heat loss is promoted by sweating and dilation of cutaneous blood vessels. sweating, dilation of cutaneous blood vessels, and nonshivering thermogenesis. nonshivering thermogenesis. sweating. dilation of cutaneous blood vessels.
sweating and dilation of cutaneous blood vessels.
The small space between the sending neuron and the receiving neuron is the calcium channel. synaptic terminal. neurotransmitter. vesicle. synaptic cleft.
synaptic cleft.
The inward extensions of the sarcolemma are called _____, and they conduct _____ into the interior of the muscle cell. t-tubules; the action potential t-tubules; calcium myofibrils; action potential myofibrils; calcium
t-tubules; the action potential
Protein specificity is the degree to which a protein is attracted to a ligand. the degree to which a protein is attracted to a ligand and the ability of a protein to bind a certain ligand or a group of related ligands. the ability of a protein to bind a certain ligand or a group of related ligands. the activation of a specific protein that is needed to perform a particular function. the degree to which a protein-ligand complex initiates a response.
the ability of a protein to bind a certain ligand or a group of related ligands.
If a signal from a sending neuron makes the receiving neuron more negative inside, the sending neuron becomes more negative inside. the sending neuron becomes more positive inside. the receiving neuron immediately generates an action potential. the receiving neuron is less likely to generate an action potential. the receiving neuron is more likely to generate an action potential.
the receiving neuron is less likely to generate an action potential.
When calcium ions enter the synaptic terminal, they cause an action potential in the sending neuron. they cause vesicles containing neurotransmitter molecules to fuse to the plasma membrane of the sending neuron. the inside of the receiving neuron becomes more negative. neurotransmitter molecules are quickly removed from the synaptic cleft. the inside of the receiving neuron becomes more positive.
they cause vesicles containing neurotransmitter molecules to fuse to the plasma membrane of the sending neuron.
The calcium-binding protein in muscle contractile units is _____. troponin actin myosin tropomyosin
troponin
Which of the following does NOT influence the time necessary for a nerve impulse to be conveyed by a particular neuron? whether axon is sensory or motor presence or absence of a myelin sheath length of the axon presence or absence of nodes of Ranvier diameter of the axon
whether axon is sensory or motor