Human Physiology: From Cells to Systems (MindTap Course List)
9th Edition
ISBN: 9781285866932
Author: Lauralee Sherwood
Publisher: Cengage Learning
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Chapter 4.3, Problem 2CYU
Summary Introduction
To write:
The description of three conformations of a voltage-gated Na+channel and indicate the membrane potential at which each of these conformations exist.
Introduction:
The Voltage-gated membrane channels consist of proteins that have many charged groups. The voltage-gated Na+ channel has 2 gates. They are- 1) Activationgate and 2) Inactivation gate. By opening and closing as a sliding door, the activation gate guards the channel's interior. The inactivation gate is an amino acid sequence with a ball-and-chain-like structure at the opening channel facing the ICF.This door is open when the ball hangs freely at the end of its chain and when the ball binds to the opening of the channel, thus blocking the opening. Both gates must be open to allow Na+ to go through the channel, and both gates must be closed to prevent passage.
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Chapter 4 Solutions
Human Physiology: From Cells to Systems (MindTap Course List)
Ch. 4.1 - Name the two types of excitable tissue.Ch. 4.1 - Prob. 2CYUCh. 4.1 - State the factor responsible for triggering gate...Ch. 4.2 - Prob. 1CYUCh. 4.2 - Prob. 2CYUCh. 4.2 - Prob. 3CYUCh. 4.3 - Draw and label an action potential, indicating the...Ch. 4.3 - Prob. 2CYUCh. 4.3 - Prob. 3CYUCh. 4.3 - Prob. 4CYU
Ch. 4.4 - Explain why synapses operate only in the direction...Ch. 4.4 - Prob. 2CYUCh. 4.4 - Prob. 3CYUCh. 4.4 - Prob. 4CYUCh. 4.5 - Define target cell.Ch. 4.5 - Distinguish among the four types of extracellular...Ch. 4.5 - Outline the three general means by which binding...Ch. 4.5 - Prob. 4CYUCh. 4.6 - Distinguish between cytokines and eicosanoids.Ch. 4.6 - Discuss the roles of phospholipase A2,...Ch. 4.6 - Prob. 3CYUCh. 4.7 - Prob. 1CYUCh. 4.7 - Prob. 2CYUCh. 4.7 - Prob. 3CYUCh. 4.8 - Prob. 1CYUCh. 4.8 - Prob. 2CYUCh. 4 - Conformational changes in channel proteins brought...Ch. 4 - Prob. 2RECh. 4 - Prob. 3RECh. 4 - Prob. 4RECh. 4 - Second-messenger systems ultimately bring about...Ch. 4 - Each steroidogenic organ has all the enzymes...Ch. 4 - Prob. 7RECh. 4 - Prob. 8RECh. 4 - Prob. 9RECh. 4 - Prob. 10RECh. 4 - Prob. 11RECh. 4 - Prob. 12RECh. 4 - Prob. 13RECh. 4 - A common membrane-bound intermediary between the...Ch. 4 - Prob. 15RECh. 4 - Prob. 16RECh. 4 - Prob. 17RECh. 4 - Prob. 18RECh. 4 - Define the following terms: polarization,...Ch. 4 - Prob. 2UCCh. 4 - Prob. 3UCCh. 4 - Prob. 4UCCh. 4 - Compare the four kinds of gated channels in terms...Ch. 4 - Prob. 6UCCh. 4 - Prob. 7UCCh. 4 - Prob. 8UCCh. 4 - Prob. 9UCCh. 4 - Define signal transduction.Ch. 4 - Compare the tyrosine kinase and JAK/STAT pathways.Ch. 4 - Prob. 12UCCh. 4 - Prob. 13UCCh. 4 - Describe how arachidonic acid is converted into...Ch. 4 - Prob. 15UCCh. 4 - Prob. 16UCCh. 4 - Explain how the cascading effect of hormonal...Ch. 4 - Prob. 18UCCh. 4 - Answer the following questions regarding...Ch. 4 - Prob. 2SQECh. 4 - Prob. 3SQECh. 4 - Prob. 1ACRCh. 4 - The rate at which the Na+K+ pump operates is not...Ch. 4 - Which of the following would occur if a neuron...Ch. 4 - Prob. 3TAHLCh. 4 - Assume presynaptic excitatory neuron A terminates...Ch. 4 - Prob. 5TAHL
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- Conformational changes in channel proteins brought about by voltage changes are responsible for opening and closing Na+ and K+ gates during the generation of an action potential. (True or false?)arrow_forwardOne of the important uses of the Nernst equation is in describing the flow of ions across plasma membranes. Ions move under the influence of two forces: the concentration gradient (given in electrical units by the Nernst equation) and the electrical gradient (given by the membrane voltage). This is summarized by Ohms law: Ix=Gx(VmEx) which describes the movement of ion x across the membrane. I is the current in amperes (A); G is the conductance, a measure of the permeability of x, in Siemens (S), which is I/V;Vm is the membrane voltage; and Ex is the equilibrium potential of ion x. Not only does this equation tell how large the current is, but it also tells what direction the current is flowing. By convention, a negative value of the current represents either a positive ion entering the cell or a negative ion leaving the cell. The opposite is true of a positive value of the current. a. Using the following information, calculate the magnitude of Na [ Na+ ]0=145mM,[ Na+ ]i=15mM,Gna+=1nS,Vm=70mV b. Is Na+ entering or leaving the cell? c. Is Na+ moving with or against the concentration gradient? Is it moving with or against the electrical gradient?arrow_forwardSeparately, draw a table using arrows to depict the appropriate magnitude and direction of the forces and ion fluxes at different membrane potentials for a ligand-gated channel that is equally permeable to both ion X+ and ion Y+. The equilibrium potential for ion X+ is -60 mV, and the equilibrium potential for ion Y+ is -20 mV. Which item (a, b, c, or d) best represents the forces and fluxes for a membrane potential of +20 mV? Upwards arrows means outward direction and downwards arrow means inward direction. The length of the arrow determines the magnitude.arrow_forward
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