Lecture 18 Introduction to Metabolism-BW

Nad and when it accepts it becomes nadh fully

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Unformatted text preview: sons donated to electron trasnport - oxygen fi nal electonr acceptor energy c ontansted in teh gradient drives ATP s ytehsis s tate 2 and 3 aerobic r espiration glysosis can happen with or without oxygen generate the most ATP for the c ell. Loss of electrons Oxygen becomes reduced 3/27/13 MCB 2000 Lecture 18 majoriy linked to ATP s ythesis - Protein s ythesis and Sodium ATPase and Ca ATPase c onsume of half of all ATP made in the c ell Redox reactions and high phosphoryl transfer potential coupled to ATP synthesis: Role of Electron Carriers NAD+ Nicotinamide adenine dinucleotide (NAD+) NAD+ accept Derived from the B vitamin, NADH -elctrsons(B3one proton Niacin isand reduced form) beomes (NADH the ) happens in apirs - loss electrosn have to go s omewhere - NAD+ elctron carrier Loss of electrons 3/27/13 Accepts a hydrogen ion and 2 electrons (hydride ion) Oxygen becomes reduced MCB 2000 Lecture 18 Where the moelcules accept elctrsons Redox reactions and high phosphoryl transfer potential coupled to ATP synthesis: Role of Electron Carriers Flavin adenine dinucleotide (FAD) Derived from the B vitamin, Riboflavin (B2) 2 B v itamin - crucial to the enrgy transporation - precursor. electron carrieres when a molecule is oxidaized Accepts 2 electrons and 2 protons 3/27/13 MCB 2000 Lecture 18 ATP levels are maintained in equilibrium by Adenylate Kinase 2 ADP ATP + AMP ATP regulatory moleucle - not ATP by itself - also mean ADP and AMP - these nutocletides are kept in equilbrium by Adenylate Kinase -Kinase c ontrol the equilbrim between ADP, ATP, and AMP - ATP is normally higher than the other two - turns out that these two molecules are lower s erve as signals for energy status - what is the erngy status of the cell? - lots of ATP? - that means lower amount of ADP and AMP - inversely r elated - the conetratino of ADP are much lower Begin to excersie 20% drop of ATP - but then ADP c oncentration 50% increase- look at AMP with excresise 500 fold increase - increased 5 times - given though c oncentration are still low - but when ATP drops by 20 % c hanging the c onetnration of AMP by 500 foldes. - small c hange in ATP - amp for AMP [ATP] ~ 2-5 mM in cells [AMP] ~ < 0.1 mM C o n se q u e n c e : S m a l l n e t c h a n ge i n A T P r es u l t s i n l a r ge c h a n ge i n A M P. A M P t h us b e com es a sign a l fo r a low e n e r gy st a t e . 3/27/13 MCB 2000 Lecture 18 Energy status can be indicated by Energy Charge Battery fully charged - the cell has lots of ATP - if the battery is low - not much charge - the cell doesnt have much ATP - instead has a lot of ADP and AMP and needs to sythesize ADP. look at the erngy c harge - ratio of conenctartion - and 1/2 ADP - ADP has two ohphate that can be given up ATP only has 1 ATP Energy charge = * Cell range [ATP] + ! [ADP] [ATP] + [ADP] + [AMP] Energy charge = 0 ; all AMP energy high - can use ATP - biosythesize enrgy r eaction only happen when the erngy charge is high if you ahve two hgih of an energy charge - tell you y ou dont need to continue to make ATP - Energy charge = 1 ; all ATP s ythesizing reactions will slow down More AMP down here Cellular range = 0.8-0.95 pathways will osicillate Energy Charge Regulates Metabolism 3/27/13 MCB 2000 Lecture 18...
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