CELLULAR RESPIRATION A cell gains useful energy (Oxygen consumed as a reactant along with organic fuel) To perform their tasks cells require E from outside sources To perform their tasks cells require E from outside sources Harvest energy stored in food with help of enzymes Harvest energy stored in food with help of enzymes The Mitochondria house most of the metabolic equipment The Mitochondria house most of the metabolic equipment

ATP is the central character ATP is the central character ATP regenerates its supply from ADP ATP regenerates its supply from ADP Glucose and other organic fuels are broken down gradually in a series of steps, each one catalyzed by a coenzyme Glucose and other organic fuels are broken down gradually in a series of steps, each one catalyzed by a coenzyme Coenzyme: small organic non-protein molecules that carry chemical groups between molecules. Ie…….. Coenzyme: small organic non-protein molecules that carry chemical groups between molecules. Ie……..

NAD+ => NADH NAD+ => NADH Redox Reactions Transfer of electrons or degree of electron sharing in covalent bonds Transfer of electrons or degree of electron sharing in covalent bonds Loss of electron – Oxidation Loss of electron – Oxidation By oxidizing glucose, respiration takes energy out of storage and makes it available for ATP synthesis By oxidizing glucose, respiration takes energy out of storage and makes it available for ATP synthesis

Electron Transport Chain Consists of several molecules, mostly proteins built into the inner membrane of mitochondrian Consists of several molecules, mostly proteins built into the inner membrane of mitochondrian NADH (top) NADH (top) Oxygen (bottom) Converts the chemical energy stored in food to a form that can be used to make ATP

Cellular Respiration is a cumulative funcion of metabolic stages: Cellular Respiration is a cumulative funcion of metabolic stages:Glycolsis Krebes Cycle Electron Transport Chain & Oxidation Phosphorylation

Glycolysis Splitting of sugar Splitting of sugar Breaks down glucose into two moleucules of a compound called pyruvate Breaks down glucose into two moleucules of a compound called pyruvate Glucose is a six carbon sugar Glucose is a six carbon sugar Oxidized to 2 pyruvate Oxidized to 2 pyruvate Occurs outside the Mitochondria Occurs outside the Mitochondria

No CO2 is released whether or not oxygen is present No CO2 is released whether or not oxygen is present 10 steps 10 steps Yields 2 ATP Yields 2 ATP

..\Illustrations\Krebes Cycle.jpg..\Illustrations\Krebes Cycle.jpg

Krebes Cycle Glycolysis releases less than ¼ of the chemical energy stored in Glucose Most remains in the 2 Pyruvate If O2 is present, Pyruvates enter the Mitochondrian First converted to Acetyl CoA junction between Glycolysis and the Krebes Cycle Catalyzed the release of 1 Co2

8 Steps Step 1 Acetyl CoA 6-carbon citrate Acetyl CoA 6-carbon citrate Step 2 Molecule of water removed then added back Citrate -> Isocitrate Molecule of water removed then added back Citrate -> Isocitrate

Step 3 CO2 molecule is lost CO2 molecule is lost Removing 5 carbon compound ie oxidized Removing 5 carbon compound ie oxidized Reducing NAD+ to NADH Reducing NAD+ to NADH Step 4 Catalyzed by a multienzyme complex Catalyzed by a multienzyme complex CO2 is lost CO2 is lost

Remaining 4-carbon compound is oxydized the transfer of electron to NAD+ -> NADH Remaining 4-carbon compound is oxydized the transfer of electron to NAD+ -> NADH Then is attached to CoenzymeA by an unstable bond Then is attached to CoenzymeA by an unstable bond Step 5 Substrate level phosphorylation (addition of a phosphate group) occurs in the step Substrate level phosphorylation (addition of a phosphate group) occurs in the step CoA is displaced & transferred to GDP -> GTP CoA is displaced & transferred to GDP -> GTP GTP donates a phosphorate group to ADP - > ATP GTP donates a phosphorate group to ADP - > ATP

Step 6 Oxidative step Oxidative step 2 hrydrogens are transferred to FAD - > FADH2 2 hrydrogens are transferred to FAD - > FADH2 Step 7 Bonds in the substrate are rearranged by the addition of a water molecule Bonds in the substrate are rearranged by the addition of a water molecule

Step 8 Produces another molecule of NADH Produces another molecule of NADH Prepares Acetyl CoA for another turn in the cycle Prepares Acetyl CoA for another turn in the cycle

Electron Transport Chain Electrons removed during glycolysis and the krebes cycle are transferred by NADH to the first molecule of the Electron Transport Chain Electrons removed during glycolysis and the krebes cycle are transferred by NADH to the first molecule of the Electron Transport Chain Function is to ease electron from food to oxygen Function is to ease electron from food to oxygen

SO WHAT DOES ALL THIS MEAN? Cellular Shock Inadequate tissue perfusion anaerobic metabolism Inadequate tissue perfusion anaerobic metabolism Cellular energy source is glucose Cellular energy source is glucose Glycolysis -- Pyruvic Acid CO2 + H20 the E Glycolysis -- Pyruvic Acid CO2 + H20 the E Hypoxia -> Glycolysis -> Pyruvic acid -> lactic acid -> cellular death -> tissue death - > organ failure -> death Hypoxia -> Glycolysis -> Pyruvic acid -> lactic acid -> cellular death -> tissue death - > organ failure -> death