At which of the following steps in a signaling pathway can amplification of the signal occur? Select all that apply. O Adenylate cyclase produces cyclic AMP. An extracellular signal molecule binds and activates a cell-surface receptor. An activated G protein activates adenylate cyclase, the enzyme that produces cyclic AMP. O Cyclic AMP activates a protein kinase (A-kinase). A-kinase phosphorylates target proteins.

At which of the following steps in a signaling pathway can amplification of the signal occur? Select all that apply. O Adenylate cyclase produces cyclic AMP. An extracellular signal molecule binds and activates a cell-surface receptor. An activated G protein activates adenylate cyclase, the enzyme that produces cyclic AMP. O Cyclic AMP activates a protein kinase (A-kinase). A-kinase phosphorylates target proteins.

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

Section: Chapter Questions

Problem 1TYU: During signal transduction (a) the cell converts an extracellular signal into an intracellular...

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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
__________ are molecules released from a signaling cell that have effects on target cells. a. Hormones b. Neurotransmitters c. Local signaling molecules d. Pheromones e. a and b f. all of the above
During signal transduction (a) the cell converts an extracellular signal into an intracellular signal that leads to a change in some cell process (b) a signaling molecule directly activates or represses several genes (c) each enzyme catalyzes production of one molecule of product (d) enzymes in the signal cascade remain active until the last component of the pathway alters a cellular process (e) the signal is terminated by cyclic AMP
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.
How is an extracellular signal converted to an intracellular signal in signal transduction? Give a specific example.
A drug binds to a receptor and causes an immediate change in the electrical signaling or excitability of that cell, without activating another signaling molecule. What type of receptor is this drug most likely binding to? G-protein coupled receptor (GPCR) Ligand-gated ion channel Enzyme-coupled receptor Intracellular receptor Voltage-gated ion channel
For a signal to be sent down an axon of a nerve cell, an action potential must be generated. This is done by.. Select one: a. G-protein coupled receptors bind ligand, a phosphorylation cascade occurs, this causes a change in charge of the membrane due to the addition of phosphates allowing Na+ channels to open. b. Ligand-gated K+ channels open, allowing K+ to rush out of the cell and depolarize that part of the membrane. This change in charge opens neighboring voltage-gated channels. c. Ligand-gated Na+ channels open, allowing Na+ to rush in. This then depolarizes that region of the membrane resulting in opening neighboring voltage-gated channels. d. Receptor tyrosine kinases have two Na+ molecules bind, this opens voltage-gated channels allowing the “signal” to pass down the axon.
All cells of a multicellular organism may not respond in the same wayto a particular ligand (signaling molecule) that binds to a cell surfacereceptor. The difference in response may be due toa. the type of receptor for the ligand that the cell expresses.b the affinity of the ligand for the receptor in a given cell type.c. the type of signal transduction pathways that the cell expresses.d. the type of target proteins that the cell expresses.e. all of the above.
The secondary messenger cyclic AMP (cAMP) is involved in many different signaling pathways, including the G protein-coupled receptor (GPCR) pathway. Which of the following describes an advantage of using cAMP as a secondary messenger in cell signaling? It conserves energy because cAMP can be converted to ATP. It increases signaling specificity because protein kinase A, the direct effector of cAMP, has few substrates. It prolongs the signal because cAMP is chemically stable and persists for a long time after ligand dissociation. It amplifies the signal because one molecule of activated adenylyl cyclase can produce many molecules of cAMP.
Except for?, all of the following signals may trigger receptor conformational changes without reaching the plasma membrane. o a. Receptors for steroid hormones. Tyrosine kinase receptors are a kind of receptor that binds to tyrosine phosphatase. Voltage-gated ion channels (OC). G protein-coupled receptors (GPCRs).
Which of the following is not correct about a second messenger system? A. The activating hormone interacts with a receptor site on the plasma membrane. B. The activating hormone activates an enzyme, most often adenylate cyclase C. Activated adenylate cyclase catalyzes the transformation of AMP to cyclic AMP D. Cyclic AMP causes the activation of protein kinase E. None of these are correct.
An extracellular signaling molecule binds to cell surface receptor. This cell surface receptor changes shape and activates a trimeric G-protein. What kind of receptor is this? a) Ion-channel coupled receptor b) Receptor Tyrosine Kinase c) G-Protein coupled receptor d) All of the other answers are correct e) Enzyme-coupled receptor