Bio 35 Study Guide

Bio 35 Study Guide - Bio 35 Study Guide #2 rtheus@uci.edu...

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Bio 35 Study Guide #2 rtheus@uci.edu Neural Communication Ions have a negative and positive charge/ an ion formed by losing one electron is represented by the element’s symbol and a plus sign/ an ion formed by losing two electrons is represented by the element’s symbol followed by two positive charges Electric currents: carried by movements of ions across membrane of cells Potential: when opposite ions are separated Electrochemical signaling: Anions: large patients with a negative charge which are synthesized/ they can’t get out of the cell The four ions that induce action potential o Large protein molecule (A-) o Potassium (K+) o Chloride (Cl-) o Sodium (Na+) Calcium ions has a higher concentration outside the cell than inside the cell Potassium moves freely through the membrane of a non-gated ion channels Chemically gated channel- chemical key opens the gate Concentration gradient: occurs when there is a compartment of concentration is high and there is a concentration is low (outside and inside the cell respectfully) o “down the concentration gradient”: ions will move from an area of high concentration to an area of low concentration It does not take energy for an ion to go down the concentration gradient o “up the concentration gradient”: ions move from an area of low concentration to an area of high concentration This takes a lot of energy Electrical forces (voltage gradient): the difference in charge between two regions that allows a flow of current if the two regions are connected. o Opposite charges will be drawn toward each other and the alike ions will repel each other o “down the voltage gradient”:move towards a compartment where there is an opposite charge o A resting neuron is a neuron that is not currently generating an action potential o Resting potential: produced by an unequal distribution of ions between inside and outside of neurons/ electrical charge across the cell membrane in the absence of
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stimulation; a store of energy produced by a greater negative charge on the intracellular side of relative to the extracellular side/ it is a store of energy that can be used as a later time. -70 millibolts: intracellular compartment is more negative inside than outside/ the difference is about -70 millibolts (resting potential- there are ions ready to rush down the concentration gradient into or out of the cell o Because there is an equal distribution of ions inside the axon than outside the cell/ due to semi-permeable membranes Sodium potassium pump: in the membrane, it takes enormous amounts of energy/ responsible for the concentration- moves sodium and potassium in opposite of its gradients (up the concentration gradient) Jack Kevorkian- “assisted suicide” o Potassium chloride screws up the concentration gradient and wipes out resting potential/ puts the neuron at equilibrium o This blocks out the neurons ability to generate an action potential A neuron does not want to be at equilibrium because it can’t generate an action
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This note was uploaded on 12/05/2009 for the course BIO SCI 324324 taught by Professor Dickin-anson during the Spring '09 term at UC Irvine.

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Bio 35 Study Guide - Bio 35 Study Guide #2 rtheus@uci.edu...

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