2. Complete the following table summarizing the 4 major types of xenobiotic receptor targets discussed in class and their generalized characteristics. lon channel Cellular localization Effect of agonist binding to the receptor Major effector molecules or downstream targets (if required) Example mechanism of receptor down- or up-regulation Cell membrane Neuromuscular junctions and neuronal synapses G-coupled Protein Receptor Receptor Tyrosine Kinase Nuclear Receptor Receptor changes conformation, intracellular domain recruits/activates G- protein DNA hormone response element – regulates transcription of targeted genes Provide a specific example of this type of receptor Nicotinic acetylcholine receptor Down-regulation: continued activation leads to auto- phosphorylation of intracellular domains, promoting ubiquitination that targets receptors for proteosomal degradation

2. Complete the following table summarizing the 4 major types of xenobiotic receptor targets discussed in class and their generalized characteristics. lon channel Cellular localization Effect of agonist binding to the receptor Major effector molecules or downstream targets (if required) Example mechanism of receptor down- or up-regulation Cell membrane Neuromuscular junctions and neuronal synapses G-coupled Protein Receptor Receptor Tyrosine Kinase Nuclear Receptor Receptor changes conformation, intracellular domain recruits/activates G- protein DNA hormone response element – regulates transcription of targeted genes Provide a specific example of this type of receptor Nicotinic acetylcholine receptor Down-regulation: continued activation leads to auto- phosphorylation of intracellular domains, promoting ubiquitination that targets receptors for proteosomal degradation

Biology (MindTap Course List)

11th Edition

ISBN:9781337392938

Author:Eldra Solomon, Charles Martin, Diana W. Martin, Linda R. Berg

Publisher:Eldra Solomon, Charles Martin, Diana W. Martin, Linda R. Berg

Chapter6: Cell Communication

Section6.4: Signal Transduction

Problem 6LO: Trace the sequence of events in signal transduction for each of the following second messengers:...

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Similar questions

Outline the three general means by which binding of a water soluble extracellular chemical messenger to its matching surface membrane receptor brings about the desired intracellular response.
Which of the following is incorrect about pathways activated by G-proteincoupled receptors? a. The extracellular signaling molecule is the first messenger. b. When activated, plasma membrane-bound G protein canswitch on an effector. c. Second messengers enter the nucleus. d. ATP converts to cAMP to activate protein kinases. e. Protein kinases phosphorylate molecules to change cellularactivity.
In the propagation of a nerve impulse: a. the refractory period begins as the K+ channel opens, allowing K+ ions to flow outward along their concentrationgradient. b. Na+ ions flow out of the axon with their concentration gradient. c. positive charges lower the membrane potential to its lowestaction potential. d. gated K+ channels open at the same time as the activationgate of Na+ channels closes. e. the depolarizing stimulus lowers the membrane potential toopen the Na+ gates.
What type of receptor requires an effector protein to initiate a signal? biogenic amine ionotropic receptor cholinergic system metabotropic receptor
Which of the following does not contribute to propagation of action potentials? a. As the area outside the membrane becomes negative, itattracts ions from adjacent regions; as the inside of the membrane becomes positive, it attracts negative ions from nearby in the cytoplasm. These events depolarize nearby regions of the axon membrane. b. The refractory period allows the impulse to travel in only one direction. c. Each segment of the axon prevents the adjacent segments from firing. d. The magnitude of the action potential stays the same as it travels down the axon. e. Up to a limit, increasing the intensity of the stimulus increases the number of action potentials.
What does a ligand-gated channel require in order to open? increase in concentration of Na+ ions binding of a neuro transmitter increase in concentration of K+ ions depolarization of the membrane
View the University of Michigan Webscope (http://openstaxcollege.org/l/nervefiber) to see an electron micrograph of a cross-section of a myelinated nerve fiber. The axon contains microtubules and neurofilaments, bounded by a plasma membrane known as the axolemma. Outside the plasma membrane of the axon is the myelin sheath, which is composed of the tightly wrapped plasma membrane of a Schwann cell. What aspects of the cells in this image react with the stain that makes them the deep, dark, black color, such as the multiple layers that are the myelin sheath?
Which of the following is probably going to propagate an action potential fastest? a thin, unmyelinated axon a thin, myelinated axon a thick, unmyelinated axon a thick, myelinated axon
Visit this site (http://openstaxcollege.org/l/neurolab) to see a virtual neurophysiology lab, and to observe electrophysiological processes in the nervous system, where scientists directly measure the electrical signals produced by neurons. Often, the action potentials occur so rapidly that watching a screen to see them occur is not helpful. A speaker is powered by the signals recorded from a neuron and it pops each time the neuron fires an action potential. These action potentials are firing so fast that it sounds like static on the radio. Electrophysiologists can recognize the patterns within that static to understand what is happening. Why is the leech model used for measuring the electrical activity of neurons instead of using humans?
You learned in this chapter that Na+/K+ active transport pumps in the plasma membrane of the axons are responsible for creating the imbalance between Na+ and K+ inside and outside of the neuron that produces the resting membrane potential. In early research studying the role of ions and the involvement of active transport of ions in neural signaling, investigators used the giant axon of a squid as a model. The diameter of a giant axon is far greater than that of a mammalian axon, which enabled researchers to isolate it easily and use it in in vitro experiments. In one early experiment, researchers investigated the active transport of Na+ out of the axon in response to the presence of cyanide. Experimentally they hooked up a section of axon to a syringe, immersed the axon in artificial seawater, introduced radioactive 22Na (as 22NaCl) into the axon, and then quantified the transport of 22Na out through the axons plasma membrane. The rate of 22Na transport out of the axon was determined by measuring the radioactivity released into the fluid sur- rounding the axon over a period of time. The Figure shows the results of the experiment. What is the effect of cyanide on Na1 transport out of the squid axon? How do the data show the effect? Source: P. C. Caldwell et al. 1960. The effects of injecting energy-rich phosphate compounds on the active transport of ions in the giant axons of Loligo. The Journal of Physiology 152:561590. Cengage Learning 2017
A common membrane-bound intermediary between the receptor and the effector protein within the plasma membrane is the __________________.
A _______________ is a drug that causes temporary paralysis by blocking the transmis- sion of nerve stimuli to the muscles. neuromuscular blocker skeletal muscle relaxant