7c final
A genetic condition called epidermolysis bullosa cause the skin to be very fragile and to blister easily. Which one of the following mutations would you expect to be cause epidermolysis bullosa? A mutation in a laminin-binding integrin gene that causes a loss of function in the cytoplasmic domains of the integrin. A mutation in a connexin gene leading to predicted truncation of the protein that leads to abnormal cell division in the epidermis. A mutation in a claudin gene that causes loss of epithelial-barrier function by allowing diffusion of solutes through the intercellular space between the cells.
A mutation in a laminin-binding integrin gene that causes a loss of function in the cytoplasmic domains of the integrin.
Suppose the stereocilia of one hair cell become permanently bent toward the kinocilium. What will most likely happen as a consequence? A single pitch will no longer be perceivable depending on the hair cell's location Many pitches will no longer be perceivable A single pitch will be constantly perceived depending on the hair cell's location Many pitches will be constantly perceived
A single pitch will be constantly perceived depending on the hair cell's location
When people have a few drinks containing alcohol, they often feel the need to urinate. This response suggests interplay between alcohol and antidiuretic hormone (ADH). Which of these statements could explain how alcohol and ADH interact? Alcohol increases the release of ADH. Alcohol decreases the release of ADH. Alcohol inhibits the binding of ADH to receptors in the brain, so individuals "feel" the need to urinate. Alcohol facilitates the binding of ADH to receptors in the brain, so individuals "feel" the need to urinate.
Alcohol decreases the release of ADH.
Aldosterone is a hormone secreted by the adrenal cortex, and insulin is a peptide secreted by the pancreas. Refer to the figures shown. 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? Aldosterone is hydrophilic and, therefore, must enter the aqueous environment of the cytoplasm to have an effect. Insulin is too large to interact chemically with DNA. Aldosterone is too small to bind extracellular receptors on the plasma membrane. Aldosterone is lipid-soluble and, therefore, easily crosses the phospholipid bilayer of the plasma membrane.
Aldosterone is lipid-soluble and, therefore, easily crosses the phospholipid bilayer of the plasma membrane.
Which statement is true? It is necessary to have a nervous system to sense and respond to the environment. All animals have a nervous system, which is necessary to sense and respond to the environment, but not all animals sense and respond to the environment. All animals have a nervous system. All animals have a nervous system and sense and respond to the environment, and a nervous system is necessary to sense and respond to the environment. All animals sense and respond to the environment.
All animals sense and respond to the environment.
If two signaling pathways are activated simultaneously: one may inhibit the other. All of these choices are correct. they may strengthen each other. they may inhibit each other.
All of these choices are correct.
Sensory transduction requires: All of these choices are correct. a change in membrane potential. reaction of a receptor protein with a stimulus. alteration of the conformation of a channel protein.
All of these choices are correct.
What does a ligand-gated channel do? It opens a channel through the plasma membrane when signal molecules bind. All of these choices are correct. It allows ions to move across the plasma membrane. It can be closed and restrict ion flow when signal molecules are absent.
All of these choices are correct.
Which of the answer choices is a cellular response to signal transduction? the release of signaling molecules from the cell a change in the activity of an enzyme a change in the proteins found in the cytosol All of these choices are correct.
All of these choices are correct.
Many birth control pills release a constant amount of synthetic estradiol and progesterone for 21 days, followed by 7 days during which no hormones are ingested. Which of the statements describes the effects of birth control pills? Birth control pills maintain constant levels of estrogens and/or progesterone so that there is no surge in LH and ovulation does not occur. Birth control pills inhibit the development of the uterine lining so that implantation of a fertilized oocyte cannot occu
Birth control pills maintain constant levels of estrogens and/or progesterone so that there is no surge in LH and ovulation does not occur.
If a mutation occurred in the cadherin gene so that the cytoplasmic domain no longer attached to the cytoskeleton, which of the following would occur? Cadherins in desmosomes would no longer be anchored to microfilaments. Cadherins in adherens junctions would no longer be anchored to microtubules. Cadherins in hemidesmosomes would no longer be anchored to intermediate filaments. Cadherins in desmosomes would no longer be anchored to intermediate filaments.
Cadherins in desmosomes would no longer be anchored to intermediate filaments.
Which roles are played by calcium ions in coordinating the activation of a muscle by motor neurons? Select all that apply. Calcium ions enter the motor endplate of the muscle fiber, causing depolarization of the muscle cell. Calcium ions diffuse into the sarcoplasmic reticulum to open actin binding sites for myosin, leading to force generation. Calcium ions are actively pumped into the sarcoplasmic reticulum to cause muscle relaxation by allowing tropomyosin to block actin binding sites. Calcium ions enter the motor neuron axon terminus to stimulate vesicle fusion and neurotransmitter release into the neuromuscular synapse. Calcium ions are released from the sarcoplasmic reticulum and bind with troponin to open actin binding sites for myosin, leading to force generation.
Calcium ions are actively pumped into the sarcoplasmic reticulum to cause muscle relaxation by allowing tropomyosin to block actin binding sites. Calcium ions enter the motor neuron axon terminus to stimulate vesicle fusion and neurotransmitter release into the neuromuscular synapse. Calcium ions are released from the sarcoplasmic reticulum and bind with troponin to open actin binding sites for myosin, leading to force generation.
When a doctor suspects that a patient may have diabetes, she will often have the patient take a glucose challenge test. After the patient drinks a large amount of sugary solution, his blood is drawn, and the circulating levels of glucose in the blood are determined. Review the graph shown. Which curve do you expect from a patient with diabetes? Curve C Curve A Curve B
Curve B
Your core body temperature set point has just decreased. As a result you... Feel cold and shiver None of the answer choices are correct Feel hot and shiver Feel cold and sweat Feel hot and sweat
Feel hot and sweat
The graphs shown represent relationships between circulating levels of luteinizing hormone (LH) and testosterone in normal men. Which of the graphs indicate negative feedback regulation of testosterone on LH? Graph 3 Graphs 1 and 2 Graphs 2 and 3 Graph 1 Graph 4
Graphs 2 and 3
In the figure shown, panel a depicts a photoreceptor and its postsynaptic cell in the dark and panel b depicts both cells in the light. What causes the change observed in this figure? This figure is incorrect; dark and light are reversed. Hyperpolarization of the rod cell in the dark causes release of a neurotransmitter. Hyperpolarization of the rod cell in the light inhibits release of a neurotransmitter. Depolarization of the rod cell in the light inhibits release of neurotransmitter.
Hyperpolarization of the rod cell in the light inhibits release of a neurotransmitter.
A stem cell is fate determined once it has received the Self Renewal signal. As result, which genes are newly expressed? (Check all that apply) ID genes SR genes DIV genes DET genes DIFF (skin) genes DIFF (neural) genes
ID genes DIV genes DET genes
Which of the options is not a general requirement for complex multicellular life? Cells must participate in a network of genetic interactions that regulate cell division. Individual cells must retain a full range of functions, including reproduction. Cells must communicate with one another. Cells must stick together. All of these choices are correct.
Individual cells must retain a full range of functions, including reproduction.
A key difference between hormonal regulation of the reproductive systems of human males versus human females is that: LH is released in males and FSH is released in females. LH and FSH are released only in females. LH and FSH are released cyclically in females, but nearly continuously in males. LH is released continuously in males and FSH is released cyclically in females. LH and FSH are released only in males.
LH and FSH are released cyclically in females, but nearly continuously in males.
Some people have low levels of calcium circulating in the blood, a condition known as hypocalcemia. While for many this disorder has little to no effect, for some it can be life-threatening. How could low levels of calcium harm an individual? Low levels of calcium would cause sustained depolarization of the presynaptic cell. Low levels of calcium would not have any effect on synaptic transmission. Low levels of calcium would result in fewer signals sent between the presynaptic and postsynaptic cell.
Low levels of calcium would result in fewer signals sent between the presynaptic and postsynaptic cell.
magine 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? The peak voltage would be higher. The period of hyperpolarization would be longer. No action potential would be generated. Threshold values would increase. The peak would occur over a longer period of time
No action potential would be generated.
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? No, the somatic nervous system is responsible for voluntary responses and is not subdivided into sympathetic and parasympathetic components. No, although the somatic nervous system controls involuntary responses, it is the autonomic nervous system that is subdivided into parasympathetic and sympathetic components. Yes, this statement is correct. The somatic nervous system has both sympathetic and parasympathetic components and controls involuntary responses. No, although the somatic nervous system does have both sympathetic and parasympathetic subdivisions, it is responsible for voluntary responses.
No, the somatic nervous system is responsible for voluntary responses and is not subdivided into sympathetic and parasympathetic components.
Which statement is true regarding sea anemones? Sponges, not sea anemones, possess what is considered to be the "simplest" nervous system found in animals. Because sea anemones are "simple" organisms, these animals only possess motor neurons; sensory neurons or interneurons are never found in sea anemones. Although sea anemones lack definitive brains, they do possess ganglia that serve a similar function to the paired ganglia of flatworms. None of the other answer options is correct. Although sea anemones possess "net-like" nervous systems, these animals have brains located at their bases (near where they would attach to rocks).
None of the other answer options is correct.
Notch and Delta are both transmembrane proteins involved in cell communication in the developing nervous system of vertebrate animals. What makes Notch different from Delta? Notch is a receptor, and Delta is a signaling molecule. Notch is a signaling molecule, and Delta is a receptor. Notch is required at higher density than Delta to alter cell fate. All of these choices are correct.
Notch is a receptor, and Delta is a signaling molecule.
Why are some mutations of Ras associated with cancer? Ras alters ion flow across the cell membrane. Ras binds to growth factor receptors. Ras is a type of second messenger. Ras activates the MAP kinase signal transduction pathway that regulates cell division.
Ras activates the MAP kinase signal transduction pathway that regulates cell division.
Kisspeptin is a signal protein in humans that initiates the secretion of gonadotropin-releasing hormone (GnRH) from neurons found in the hypothalamus. Endocrinologists are finding that kisspeptin and its receptor are important for sexual maturation at puberty. Neurons that release kisspeptin contain cytosolic estrogen receptors and respond to high levels of estrogen by decreasing kisspeptin secretion. Given what you know about cell signaling and signal molecules, which statement is true? Receptors for kisspeptin would be found on the plasma membrane of cells of the hypothalamus. Kisspeptin synthesis will increase when estrogen levels are high. High levels of GnRH will increase Kisspeptin synthesis. Estrogen activates a receptor tyrosine kinase.
Receptors for kisspeptin would be found on the plasma membrane of cells of the hypothalamus
Sensory cells and sensory neurons allow multicellular animals to sense physical and chemical cues from their environment. What key properties of these cells enable them to perform this function? Select all that apply. Sensory cells and sensory neurons have electrically excitable membranes that change in charge potential in response to binding an environmental signaling molecule. All sensory cells and sensory neurons fire action potentials when they bind a signaling molecule. Sensory cells and sensory neurons have protein receptors linked to intracellular or membrane-based signaling pathways that alter ion channel permeability. Sensory neurons have myelinated dendrites that serve as nerve endings.
Sensory cells and sensory neurons have electrically excitable membranes that change in charge potential in response to binding an environmental signaling molecule. Sensory cells and sensory neurons have protein receptors linked to intracellular or membrane-based signaling pathways that alter ion channel permeability.
Low levels of iodine will cause a decrease in the synthesis of which of the following? (Select all that apply) TSH Thyroglobulin T3 TRH T4
T3 T4
What would happen to this signaling pathway if phosphatases had reduced levels of function? The signal will initiate expression of target genes for TF 2. There would be no change in the response to the signal. P3 will be dephosphorylated in the absence of the signal. Target genes for TF 1 would be expressed in the presence of the signal.
Target genes for TF 1 would be expressed in the presence of the signal.
The figure shows how normal signaling works with a Ras protein acting downstream of a receptor kinase. You examine a cell line in which Ras is always activated even in the absence of a signaling molecule. This causes constant activation of the kinases in the MAP kinase pathway. Which condition would be most likely to turn off this abnormally active signaling pathway? The addition of a drug that prevents the phosphorylation of the receptor kinase. The addition of a drug that increases the binding affinity of Ras for MAP kinase enzymes in the cytoplasm. The addition of a drug that prevents the dimerization of the receptor kinase. The addition of a drug that prevents the final kinase from interacting with its target protein in the nucleus.
The addition of a drug that prevents the final kinase from interacting with its target protein in the nucleus.
One example of a cellular response to a signal is the triggering of cell division. If a mutation occurred in the gene for the signal receptor in this pathway that caused the receptor to reject binding of the signal, what response can be predicted? The signal is not produced. The cell does not divide. The cell divides repeatedly without the signal.
The cell does not divide.
Which of the answer choices is an example of negative feedback altering homeostatic control? The production of oxytocin (a hormone) increases in a pregnant woman's body as oxytocin levels in her body rise. A person's heart rate remains elevated over the course of a long run. A person with a bacterial infection runs a fever and his body temperatures rises and stays elevated for several days. The concentration of salt in a person's urine increases after that person eats a large bag of salty chips.
The concentration of salt in a person's urine increases after that person eats a large bag of salty chips.
Aging can sometimes lead to an increase in the stiffness at the base of the basilar membrane. What affect would this have on a person's hearing? The person would not be able to distinguish the amplitude of a sound. The person would only be able to hear loud sounds. The person would lose the ability to hear low-pitched sounds. The person would lose the ability to hear high-pitched sounds.
The person would lose the ability to hear high-pitched sounds.
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? The signal would still bind the receptor, so there would be no effect. The response of the cell would last longer than it normally would. The response of the cell would be shorter than it normally would.
The response of the cell would last longer than it normally would.
A stem cell continuously expresses the DIV and ID genes. Which of the following could cause this inhibition of differentiation? (Mark all that apply) The skin pathway receptor is not able to autophosphorylate when the skin signal is present. The neural pathway transducer P1 acts as a phosphatase that would target transducer P2 of the skin pathway. The neural pathway transducer P2 is always phosphorylated. The neural signal is over expressed.
The skin pathway receptor is not able to autophosphorylate when the skin signal is present.
Gap junctions are a complex of integral membrane proteins called connexins arranged in a ring. In plasmodesmata, the plasma membranes of the two connected cells are actually continuous. Gap junctions and plasmodesmata have what feature in common? They are both found in plant cells. They both allow direct transport of materials between cells. They both attach to the cytoskeleton. They both are made up of protein subunits located in the plasma membrane.
They both allow direct transport of materials between cells.
Epithelial cells that line the digestive system are responsible for absorption and secretion of materials across the cell's plasma membrane. If a mutation occurred in the claudin gene that make up tight junctions, which of the following would occur? Transport of digestive enzyme-filled vesicles will not occur within cells. Transport of materials will passively occur across the plasma membrane. Transport of materials in between cells will increase. Transport of materials in between cells will decrease.
Transport of materials in between cells will increase.
A cell in a chick embryo is tested to determine whether it is a stem cell of some kind. These tests find: 1. The SR receptor is present 2. DIV genes are on 3. The DIFF (skin) genes are blocked 4. TF of the neural pathway is in the cytoplasm 5. Transducer 2 of the skin pathway is not phosphorylated For the following statement answer True or False: Based on these results, this cell will not differentiate into a neural cell. True False
True
What is the end-result of activating the MAP kinase pathway? synthesis of second messenger molecules ion flow phosphorylation of multiple cytosolic proteins a change in gene expression
a change in gene expression
Which of the answer choices would be considered a cell-surface receptor? a protein that binds a nonpolar steroid hormone and activates transcription a protein that acts as an enzyme that attaches phosphate groups to substrates a protein that forms a channel that allows ions to enter the cell when a ligand binds a protein that causes GDP to be exchanged for GTP in a G protein
a protein that forms a channel that allows ions to enter the cell when a ligand binds
A researcher is using a small molecule inhibitor that prevents phosphorylation as a tool to manipulate a signaling pathway. What is the most likely target of this small molecule inhibitor? a G protein-coupled receptor a ligand-gated ion channel a phosphatase a G protein α subunit a receptor kinase
a receptor kinase
Which type of cell-surface receptor undergoes changes in phosphorylation in response to binding of its ligand? a G protein-coupled receptor both the G protein-coupled receptor and the receptor kinase a receptor kinase a ligand-gated ion channel
a receptor kinase
In the context of cell signaling, to what does the term ligand refer? a type of gated channel the proteins activated as part of a signal transduction pathway a signaling molecule that binds to the receptor the extracellular domain of a receptor protein
a signaling molecule that binds to the receptor
If a skeletal muscle is no longer able to make enough ATP, then: actin and myosin in the sarcomeres will remain bound. actin and myosin in the sarcomeres are in the unbound state. there will be low levels of acetylcholine at the motor endplate. the muscle will be unable to shorten.
actin and myosin in the sarcomeres will remain bound.
Consider the image. Atropine is a poison that blocks nerve action by binding to acetylcholine (Ach) receptors. Where would you expect to find atropine bound on the figure? at letter C at letter D at letter E at letter C, letter D, letter E, and letter F at letter F
at letter E
Which of the answer choices correctly lists the types of cellular communication from shortest to longest distance traveled by the signaling molecule to reach its responding cell? autocrine, paracrine, endocrine autocrine, endocrine, paracrine paracrine, autocrine, endocrine endocrine, paracrine, autocrine
autocrine, paracrine, endocrine
You measure levels of Ca2+ in various locations within a motor neuron and a skeletal muscle fiber when the motor neuron is depolarized, and the muscle fiber is actively shortening. Where do you expect to find higher levels of Ca2+? in vesicles within the motor neuron bound to troponin binding to the receptors at the motor endplate of the muscle cell diffusing into the axon terminus of a motor neuron through specialized channels in the plasma membrane bound to myosin bound to tropomyosin within the sarcoplasmic reticulum
bound to troponin
Kisspeptin is a protein that, in humans, has an important role in initiating secretion of the releasing factor gonadotropin-releasing hormone (GnRH). Endocrinologists are finding that the protein kisspeptin and its receptor are central to sexual maturation at puberty. Neurons that release kisspeptin carry estrogen receptors. If this is a negative feedback system, high levels of estrogen would be expected to: neither increase nor decrease kisspeptin synthesis because steroid hormones do not affect protein synthesis. decrease kisspeptin synthesis. increase kisspeptin synthesis.
decrease kisspeptin synthesis.
Blood glucose begin to increase after a meal. As a result, glucagon levels must _________ while insulin levels must ________ in order to maintain metabolic homeostasis. stay the same; increase decrease; increase decrease; stay the same increase; decrease
decrease; increase
Which scenario would be most likely to result in an action potential within the postsynaptic cell? dendrites: low-frequency excitatory postsynaptic potential (EPSP); cell body: high-frequency inhibitory postsynaptic potential (IPSP) dendrites: high-frequency excitatory postsynaptic potential (EPSP); cell body: high-frequency inhibitory postsynaptic potential (IPSP) dendrites: low-frequency inhibitory postsynaptic potential (IPSP); cell body: high-frequency excitatory postsynaptic potential (EPSP) dendrites: high-frequency inhibitory postsynaptic potential (IPSP); cell body: low-frequency excitatory postsynaptic potential (EPSP)
dendrites: low-frequency inhibitory postsynaptic potential (IPSP); cell body: high-frequency excitatory postsynaptic potential (EPSP)
The first step following platelet-derived growth factor (PDGF) binding of the receptor is: phosphorylation of the receptor. dimerization of the receptor. activation of MAP kinase. activation of gene expression.
dimerization of the receptor.
Mammalian steroid hormones are signaling molecules that function in which type of cell signaling? autocrine paracrine endocrine All of these choices are correct.
endocrine
Which signaling system involves the longest distance between release of a signaling molecule and activation of a receptor? endocrine paracrine contact-dependent autocrine
endocrine
The presence of excess epidermal growth factor (EGF) receptors can result in: excessive cell division. normal cell division. diminished cell division.
excessive cell division.
A cell can only respond to signals from other cells, not from the physical environment. true false
false
Most ligands form covalent bonds with their associated receptors, these complexes are more or less permanent and can only be broken through the hydrolysis of ATP. true false
false
Referring to the graph shown, indicate whether the statement is true or false. The changes in voltage seen at point 2 and point 4 in the figure are caused by similar movements, in the same direction, of the same ions across the membrane. true false
false
The changes in voltage shown in the figure are due to ligand-gated ion channels opening and closing along the axon. true false
false
The magnitude of the action potential is correlated with the strength of the stimulating input. true false
false
The trace (blue) line in the figure is following the voltage change as it moves down the axon. true false
false
Kohler and Lipton first discovered platelet-derived growth factor (PDGF) by observing that fibroblasts: grew better in cell culture blood plasma without the proteins released by platelets. grew at the same rate in cell culture containing either blood plasma or serum. grew better in cell culture containing blood serum containing proteins released by platelets during clotting.
grew better in cell culture containing blood serum containing proteins released by platelets during clotting.
Glutamate is the neurotransmitter released at the rod-bipolar cell synapse. When there is light, the rod membrane potential will ____________ due to _________ of cations through the channel. depolarize; entry hyperpolarize; exit hyperpolarize; entry depolarize; exit
hyperpolarize; exit
You turn on a light so you can get a glass of water. BEFORE you turn on the light, your bipolar cells are __________________. None of the above. (Bipolar cells do not have membrane potentials) hyperpolarized depolarized
hyperpolarized
Finger-like membrane extensions, known as microvilli, are supported by the actin cytoskeleton. Microvilli located at the apical surface of epithelial cells are responsible for: increased communication between cells. increased rates of cell division in response to signaling molecules. increased adhesion to the extracellular matrix to strengthen the tissue. increased surface area for nutrient absorption of digested food.
increased surface area for nutrient absorption of digested food.
Which of the answer choices is an example of the effector's role in maintaining homeostasis? increased sweating on a hot summer day increased body temperature during a workout vasodilation on a cold winter day decrease in body temperature on a cold day
increased sweating on a hot summer day
You turn on a light so you can get a glass of water. At the moment the light turns ON, the amount of GTP bound to the Gα subunit of trimeric G proteins __________. increases decreases does not change
increases
When iodine intake is too low, the anterior pituitary gland: increases thyroxine production. decreases thyroxine production. decreases triiodothyronine production. decreases TSH production. increases TSH production.
increases TSH production.
Which type of protein adds a phosphate group to another molecule? phosphorylase G protein kinase phosphatase
kinase
Shown 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 either U or V is required to activate W, which ligands result in W being active? Select all that apply. None of the other answer options is correct. ligand M ligand L ligand K ligand H
ligand M ligand K ligand H
Imagine you created a toxin such that binds to the sodium-potassium pump. The toxin binds immediately to the sodium-potassium pump at the peak of the action potential but does not alter the function of sodium and potassium channels. Which of the processes would the toxin prohibit in the neuron? Select all that apply. maintaining resting potentialreturning to resting potential after the hyperpolarization phase of an action potentialthe depolarization phase of an action potentialthe hyperpolarization phase of an action potential
maintaining resting potential returning to resting potential after the hyperpolarization phase of an action potential
In a study of tadpole coloration, you noticed that a certain percentage of tadpoles in a population displayed a decreased ability to shift from dark coloration at night to light coloration during the day. These individuals were studied and found to have the normal number of melanophores and these melanophores produced normal amounts of melanin pigment granules. You remember reading that pigment granule transport in melanophores involves the cytoskeleton. Which part of the cytoskeleton would you suggest investigating as a potential source of the faulty color adjustment in these tadpoles? intermediate filaments microtubules microfilaments
microtubules
Macrophage cells undergo a process called phagocytosis in which material is brought into a cell in the form of membrane vesicles and then transported along microtubules toward the cell center. Assuming that the centrosome is near the cell center, you can predict that these vesicles are moving to the _____ end of microtubules using the motor protein _____. minus end; kinesin plus end; kinesin plus end; dynein minus end; dynein
minus end; dynein
Sensory neurons are involved in all of the processes except: muscle contraction. taste. vision. hearing.
muscle contraction.
A receptor that is inside the cell would require a ______ signal molecule that can ______ the plasma membrane. polar; bind to nonpolar; bind to polar; pass through nonpolar; pass through
nonpolar; pass through
Growth factors such as platelet-derived growth factor (PDGF) function in: contact-dependent signaling. autocrine signaling. paracrine signaling. endocrine signaling.
paracrine signaling.
Signal molecules that are ______ usually have their corresponding receptor ______ of the cell. polar; on the surface polar; in the cytoplasm nonpolar; on the surface
polar; on the surface
Which is the correct order for these steps in cell signaling? response, signal transduction, termination receptor activation, signal transduction, response receptor activation, response, signal transduction signal transduction, receptor activation, response
receptor activation, signal transduction, response
In many signaling pathways, once a signaling molecule binds to a receptor, the receptor becomes phosphorylated. This initial phosphorylation step best demonstrates: either cellular response or signal transduction. signal transduction. receptor activation. cellular response. termination.
receptor activation.
For multicellularity to develop, there must be a mechanism of signaling among cells in the multicellular organism. Which of the structures in the cell membrane receives signals from the environment or from other cells? receptors cadherins gap junctions plasmodesmata
receptors
The outward movement of K+ ions from inside a neuron (Mark all that apply) repolarizes the membrane potential establishes resting membrane potential generates inhibitory postsynaptic potentials generates excitatory postsynaptic potentials
repolarizes the membrane potential establishes resting membrane potential generates inhibitory postsynaptic potentials
When an environmental stimulus is received, the signal is usually transmitted through three types of nerve cells. In which order is the signal transmitted through these cells? motor neurons, interneurons, sensory neurons interneurons, sensory neurons, motor neurons motor neurons, sensory neurons, interneurons sensory neurons, motor neurons, interneurons sensory neurons, interneurons, motor neurons
sensory neurons, interneurons, motor neurons
A ______ expresses a gene or genes that direct production of the signaling molecule, and the ______ expresses a gene or genes that direct production of the ______. responding cell; receptor protein; signal protein responding cell; signaling cell; receptor protein signaling molecule; responding cell; signaling cell signaling cell; responding cell; receptor protein
signaling cell; responding cell; receptor protein
When cells communicate by the signaling process, one cell produces a ______ that must be received by the ______ on or in the responding cell. signaling particle; signal enzyme hydrophilic signal; hydrophilic receptor nonpolar signal; nonpolar receptor signaling molecule; signal receptor cell division signal; plasma membrane
signaling molecule; signal receptor
Which of the scenarios will most likely trigger an action potential? Select all that apply. single excitatory postsynaptic potentials (EPSPs) arriving simultaneously at several different synapses (spatial summation) on the postsynaptic cell an excitatory postsynaptic potential (EPSP) and an inhibitory postsynaptic potential (IPSP) arriving simultaneously on the postsynaptic cell (cancellation) multiple excitatory postsynaptic potentials (EPSPs) arriving close in time at a single synapse (temporal summation) on the postsynaptic cell
single excitatory postsynaptic potentials (EPSPs) arriving simultaneously at several different synapses (spatial summation) on the postsynaptic cell multiple excitatory postsynaptic potentials (EPSPs) arriving close in time at a single synapse (temporal summation) on the postsynaptic cell
Type 1 and type 2 diabetes mellitus have different underlying causes. Type 1 diabetes is characterized by a loss of the insulin-producing cells of the pancreas, leading to insulin deficiency. Type 2 diabetes, at least in its early stages, is characterized by a loss of sensitivity to the hormone insulin by cells that normally respond to the hormone. Consider the diagram. Which step labeled in the diagram shown is inhibited in both type 1 and type 2 diabetes (either directly or indirectly)? step c: sensory input to the pancreas step e: glycogen hydrolysis step b: hormone release step a: glycogen synthesis step d: hormone release
step a: glycogen synthesis
Which function is not a role of an interneuron? relaying information from sensory to motor neurons maintaining homeostasis stimulating a muscle to contract conveying information within the internal environment of an animal
stimulating a muscle to contract
Which statement would result in tetanus? stimulating a muscle fiber to contract immediately after it has relaxed stimulating a muscle fiber to contract when it has partially relaxed allowing a muscle fiber to relax for several seconds between twitches stimulating the muscle fiber so frequently that it cannot relax at all
stimulating the muscle fiber so frequently that it cannot relax at all
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 process is this an example? spatial summation action potential temporal summation hyperpolarization
temporal summation
The ability of a specific tissue or organ to respond to the presence of a hormone is dependent on: nothing; all hormones of the body are able to stimulate all cell types because hormones are powerful and nonspecific. the membrane potential of the cells of the target organ. the presence of the appropriate receptors on the cells of the target tissue or organ. the location of the tissue or organ with respect to the circulatory path.
the presence of the appropriate receptors on the cells of the target tissue or organ
Some researchers have suggested that obesity is due to a change in "set point" in the brain that is related to the number of calories a person needs. People whose set point has increased eat more than they need and gain weight. Permanently raising the set point would involve a permanent change in which of the answer choices? the stimulus the effector the response the sensor
the sensor
Dilated pupils, inhibited digestive activity, increased respiratory rate, and release of glucose from the liver are all signs of activity of: both divisions of the autonomic nervous system. the sympathetic division of the autonomic system. the parasympathetic division of the autonomic system. the somatic nervous system.
the sympathetic division of the autonomic system.
How does an "activated" receptor transfer information into the cell? by decreased phosphorylation of the receptor by altering the ligand-binding site of the receptor through a conformational change of the receptor by increased translation of the receptor
through a conformational change of the receptor
Signaling molecules involved in paracrine and autocrine signaling: travel by diffusion. remain attached to the plasma membrane. travel in the circulatory system.
travel by diffusion.
Although animal nervous systems differ in complexity, their nerve cells are still remarkably similar. true false
true
An excitatory postsynaptic potential (EPSP) of sufficient strength to reach threshold occurred at point 1 on the figure. true false
true
Signaling pathways have been conserved in a wide range of organisms. true false
true
The ability of cells to adhere to one another is fundamental to multicellularity. true false
true
When compared to the leg muscles of an Olympic sprinter, the muscles of an Olympic marathoner would likely show a greater proportion of oxidative slow-twitch fibers. true false
true
Many of the signaling pathways used for signaling between cells in complex multicellular organisms first evolved in: unicellular prokaryotes. simple multicellular eukaryotes. unicellular eukaryotes. simple multicellular prokaryotes. complex multicellular prokaryotes.
unicellular eukaryotes.
Refer to the figure shown. The transduction of sound waves to changes in membrane potential takes place: in the oval window, which vibrates at the same frequency as the original sound. when stereocilia bend against the tectorial membrane, causing hair cell depolarization. as the vibrations received by the outer ear cause the eardrum to vibrate. in the basilar membrane as it vibrates at different locations. within the tectorial membrane as it is stimulated by the hair cells.
when stereocilia bend against the tectorial membrane, causing hair cell depolarization
