Endothelins are 21-amino acid vasoconstricting peptides produced primarily in the endothelium. They have an important role in vascular homeostasis. Endothelin activates G protein-coupled receptors (GPCRs) ETA or ETB on a target cell. Which subunit of heterotrimeric G protein is released when the receptor is activated? a.) gamme b.) beta c.) alpha

Endothelins are 21-amino acid vasoconstricting peptides produced primarily in the endothelium. They have an important role in vascular homeostasis. Endothelin activates G protein-coupled receptors (GPCRs) ETA or ETB on a target cell. Which subunit of heterotrimeric G protein is released when the receptor is activated? a.) gamme b.) beta c.) alpha

Human Physiology: From Cells to Systems (MindTap Course List)

9th Edition

ISBN:9781285866932

Author:Lauralee Sherwood

Publisher:Lauralee Sherwood

Chapter4: Principles Of Neural And Hormonal Communication

Section: Chapter Questions

Problem 5RE: Second-messenger systems ultimately bring about the desired cell response by inducing a change in...

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A) Please explain what a G protein coupled receptor is. Please explain how G protein interacts with this receptor. B) Please explain the kind of reactions that follow binding a specific ligand to a G protein coupled receptor. What do these reactions do in the cell? C) How do these reactions work in the cell. What is the function of these reactions in the cell? How do the reactions proceed?
The Structure of the acetylcholine receptor is shown below: A. Knowing the amino acid sequence of this protein, what tool would you use to identify the membrane-spanning region? Explain how it works.
It is important for the cell to be able to terminate responses, and diminish responsiveness to prevent overstimulation. Cells have different mechanisms for this. One such mechanism is receptor down regulation. a.) Down regulation describes a decrease in the availability of hormones or neurotransmitters that bind to receptors on the surface of target cells, making the cells less likely to be stimulated. b.) Down regulation describes glycosylation of receptor proteins receptors on the surface of target cells in order to decrease the selectivity of ligand binding, making the cells less sensitive to a hormone or neurotransmitter. c.) Down regulation describes a decrease in the number of receptors on the surface of target cells, making the cells less sensitive to a hormone or neurotransmitter.
taw a graph representing the changes in membrane potential across the axonal membrane before, during, and after an action potential, On your graph, use a highlighter to clearly indicate for which portions of your graph the letter corresponding to each cellular event listed below belongs. List of cellular events: A) All K* channels open B) All Nat channels close C) The Na*/K* ATPase cotransporter transports Nat and K* across the membrane. D) All Na* channels open E) The threshold value of membrane potential is attained. F) All K* channels close G) Some Nat channels open Your graph: o pe cffecton
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1. Ionotropic GABA receptors are ligand-gated Cl channels which open during GABA-ergic signaling. a) Describe how under normal circumstances the opening of these channels leads to an IPSP. Do this in the context of Eci. b) Some cells in the body express a Na*/K+/2Cl cotransporter which pumps Cl- into the ICF. Where these pumps are present, the same GABA receptor is actually excitatory. Again, in the context of Ea describe how the same receptor would be excitatory in cells which actively pump Cl- into the ICF. You do not need to repeat information you provided in part (a)
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1)The concept of saturation is defined as? a) The ability of a receptor to bind only one type or a limited number of structurally related types of chemical messengers. b) The degree to which receptors are occupied by messengers. c) A decrease in the total number of target-cell receptors for a given messenger d) The increased responsiveness of a target cell to a given messenger 2. Phosphodiesterase activity produces one of the following actions a) Breakdown cAMP b) Increases cAMP c) Increases PKC activity d) Increases cytosolic IP3 levels 3. Phospholipase C leads to one of the following? a) Increase in cAMP b) Breakdown of cAMP c) Increase in cytosolic levels of IP3 and DAG d) A decrease in cytosolic Ca++ concentration
Explain the role, using diagrams wherever possible, of G protein coupled receptors mediating the following physiological effects. a. Positive inotropic and positive chronotropic effects in the heart b. Vasoconstriction in vascular smooth muscle cells.
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The fight-or-flight reaction prepares an animal to Pesponu Lu a threatening situation, by either fighting or running away. One aspect of this response is changes in blood flow such that the skeletal muscles and heart receive higher blood flow (vessels dilate) while digestive organs receive less (vessels constrict). A) Which signal molecule(s) is/are involved in this response, and how do they produce these changes in blood vessels? Briefly explain how this example illustrates how different cells are able to use the same ligands in different ways.
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