Bio


Metabolism is All Chemical Changes in Cell


Metabolism consists of anabolism + catabolism


Catabolism involves breakdown of nutrients


nutrients are proteins, carbohydrates, fats; proteins break down into amino acids; carbohydrates break down into glucose; fats break down into glycerol + fatty acids;


Deamination


is removal of amino groups from amino acids to produce urea, primary excretory product of humans


Anabolism


is build-up of larger molecules from small ones; anabolism requires energy; energy supplied by ATP


Cellular Respiration


Respiration


is step-wise release of energy from molecules; aerobic respiration requires O2 and gives off CO2


Relationship between Breathing + Eating + Cellular Respiration


Oxygen is inhaled and Glucose ingested as food carried through blood into cells of digestive tract, then into mitochondria; ATP produced + CO2, which is exhaled from lungs


Overview of Cellular Respiration


Equation:


Glucose + 6 O2 in presence of ADP + P ? 6 CO2 + 6 H20 + ATP (HIGH ENERGY)Almost all organisms on land or in water carry on cellular respiration


NAD+ and FAD are coenzymes involved in cellular respiration


coenzymes are organic non-protein molecules and help enzymes function properly


Phases of Cellular Respiration


Glycolysis + Preparatory Reaction + Citric Acid Cycle + Electron Transport Chain


Glycolysis


takes place within cytoplasm but outside of mitochondria; produces pyruvate and net gain of 2 ATPs


Preparatory Reaction occurs inside mitochondria


pyruvate transported into mitochondria and is oxidized into C2 acetyl group;


Citric Acid Cycle occurs in matrix of mitochondria;


cyclical series of reactions that give off CO2 and produce 1 ATP per cycle; cycle runs twice for each glucose metabolized; therefore, 2 ATPs produced


Electron Transport Chain


is series of carriers that accept electrons (but not H+) removed from glucose; occurs across membrane of cristae; results in 32 or 34 ATPs


Cellular Respiration


involves breakdown of Glucose into CO2 + Water + Energy in form of ATP


Each Glucose metabolized yields 36 or 38 ATPs [2 ATPs from Glycolysis + 2 ATPs from Citric Acid Cycle + 32 or 34 ATPs from Electron Transport Chain]


Glycolysis Outside of Mitochondria


Glycolysis


is breakdown of Glucose (6 carbons) into two Pyruvates (each is 3 carbons)?


Energy-investment steps:


two ATPs used to activate Glucose into two C3 molecules


Energy- harvesting steps


four ATPs synthesized; four ATPs minus two ATPS = NET GAIN of two ATPs


Preparatory Reaction Inside Mitochondria


Occurs in matrix of mitochondria


Preparatory reaction


produces a molecules that can enter Citric Acid Cycle


Preparatory reaction is oxidation reaction


hydrogen atoms removed from Pyruvate


Reactions occurs twice per glucose molecule metabolized


Citric Acid Cycle


Occurs within matrix of mitochondria


Starts with C2 acetyl group carried by Coenzyme A; cycle ends with production of Citrate


Citrate is same as Citric Acid


two citrates produced from each Glucose metabolizedOutput of Citric Acid Cycle: 4 CO2 + 6 NADH + H+ 2 FADH2 + 2 ATP


Electron Transport Chain


Located in cristae of mitochondria


Electrons passed from one carrier to another


energy is used to produce ATP


Cytochromes


are electron carriers in Electron Transport Chain


Chemiosmosis


occurs within Inter-membrane Space of cristae; synthesis of ATPs


Electron Transport Chain


produces net gain of 32 or 34 ATP molecules


Energy Yield and Efficiency of Cellular Respiration


Glycolysis yields


2 ATPs


Citric Acid Cycle yields


2 ATPs


Electron Transport Chain


yields 32 or 34 ATPs


Total energy yield from metabolism of one glucose


is 36 or 38 ATPs


Efficiency of cellular respiration


is 39% of available energy from one glucose


Fermentation


Fermentation


occurs when no Oxygen available


Anaerobic


refers to lack of oxygen


Animals:


When oxygen is not available, two Pyruvates formed from one Glucose is converted into two Lactates + net gain of two ATPs


Yeast or bacteria


pyruvates converted into two alcohols + two CO2 + net gain of two ATPs


Lactate is toxic to cells


Lactate is Lactic Acid; lactic acid in blood lowers pH; makes muscles �burn�


Oxygen debt�


is amount of oxygen needed to convert lactate back into pyruvate