Section Handout #1

# Section Handout #1 - Hanna Shim [email protected]/* <![CDATA[ */!function(t,e,r,n,c,a,p){try{t=document.currentScript||function(){for(t=document.getElementsByTagName('script'),e=t.length;e--;)if(t[e].getAttribute('data-cfhash'))return t[e]}();if(t&&(c=t.previousSibling)){p=t.parentNode;if(a=c.getAttribute('data-cfemail')){for(e='',r='0x'+a.substr(0,2)|0,n=2;a.length-n;n+=2)e+='%'+('0'+('0x'+a.substr(n,2)^r).toString(16)).slice(-2);p.replaceChild(document.createTextNode(decodeURIComponent(e)),c)}p.removeChild(t)}}catch(u){}}()/* ]]> */ OH...

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Hanna Shim [email protected] OH: Tuesday 4-5PM @ Roma BIPN 100 Hand-Out #1 Sign-Preserving (or Sign- Conserving) Connection Sign-Inverting Connection Two variables linked by this kind of connection will move in the same direction Two variables link by this kind of connection will move in opposite directions i.e.: A –>B; if A increases, B will increase and if A decreases, B will decrease i.e.: A –>B; if A increases, B will decrease and if A decreases, B will increase Positive Feedback Negative Feedback Displays an even number of sign- inverting connections (even number of negative signs with the LOOP; remember that arrows have to point in one direction and that the loop needs to be closed for one variable to have an effect on another) Displays an odd number of sign- inverting connections (odd number of negative signs within the LOOP) Homeostasis The maintenance of relatively constant conditions in the body Achieved most commonly through negative feedback Common in the body “Allostasis” describes the controlled regulation at a new value (kinda like “homeostasis” after body conditions have changed; i.e. fever) Driving force = V m – E x V m = the transmembrane (or membrane) potential [may or may not be the resting potential; needs to be measured] E x = the equilibrium potential of an ion “x” [can be calculated using the Nernst equation] *If a particular ion channel is open, the ion will move in the direction which allows

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## This note was uploaded on 04/11/2008 for the course BIPN 100 taught by Professor French during the Spring '07 term at UCSD.

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Section Handout #1 - Hanna Shim [email protected] OH...

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