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RESPIRATION (has two meanings...) * the life function which involves the transfer of potential (stored) chemical energy into a form that an organism can use--CELLULAR RESPIRATION * the exchange of gases (namely CO2 and O2) between the organism and the environment--ORGANISMAL RESPIRATION I. Cellular Respiration * energy is released from glucose (a carbohydrate...a monosaccharide) * this energy is converted by enzymes (a protein...a polypeptide) to a more usable form called ATP ATP = adenosine triphosphate * all cells carry out cellular respiration * all cells use ATP triphospate= 3 phosphates * ATP = ENERGY!!! the bonds between the phosphates are high energy bonds * when these bonds are broken (that is, when ATP is hydrolyzed) lots of energy is released that can be used by the organism THE REACTION... ATP + H2O <====> ADP + P + * ATP (adenosine triphosphate) is hydrolyzed (split with water) to form ADP (adenosine diphosphate) and energy diphosphate--2 phosphates THE ATP-ADP CYCLE * ATP and ADP are constantly converting back and forth with the help of the the ATP/ADP cycle is described here enzyme ATP-ase ATP ---> ADP releases energy ADP ---> ATP needs energy okay...back to cellular respiration Respiration * cellular respiration (releasing the chemical energy of glucose to form ATP which is used for energy) can happen with or without oxygen (O2) ANAEROBIC RESPIRATION--does not use O2 AEROBIC RESPIRATION--uses O2; most organisms carry out aerobic respiration A) Anaerobic Respiration (Fermentation) * the breakdown of glucose without oxygen * some organisms like bacteria (KINGDOM--Monera) and yeast (KINGDOM-Fungi) do not have the necessary enzymes to use oxygen * other cells use anaerobic respiration (fermentation) when no O2 is present * the enzymes for anaerobic respiration (fermentation) are found in the cytoplasm * during anaerobic respiration (fermentation) glucose is broken down to either lactic acid or alcohol/CO2 depending on the organism LACTIC ACID--muscle fatigue in animals; also produced by bacteria; used to make cheese, buttermilk and yogurt ALCOHOL and CO2--produced by yeast; used in baking and brewing The reaction of anaerobic respiration (fermentation)... * it takes 2 ATP molecules of energy to break down glucose, which gives off 4 ATP...this means there is a NET GAIN of 2 ATP for anaerobic respiration (fermentation) glucose ------> 2 lactic acid both sets of end products can be used to get more energy) glucose ------> 2 alcohol + 2 CO2 The process of breaking down glucose to start cellular respirstion is called... watch the basics of glycolysis GLYCOLYSIS So, glycolysis (the breakdown of glucose) results in the formation of 2 pyruvic acid and a net gain of 2 ATP. The pyruvic acid is then converted to either lactic acid or alcohol and carbon dioxide without the production of any more ATP. B) Aerobic Respiration Respiration * the breakdown of glucose with oxygen * the energy from glucose is released gradually in a series of enzyme controlled steps (the electron transport chain) * the enzymes for aerobic respiration are found in the mitochondria THE OVERALL PICTURE... glucose + oxygen -----> water + carbon dioxide + ATP C6H12O6 + O2 ------> H2O + CO2 + 36 ATP a brief review of aerobic respiratio see the basic reactants and products of aerobic respiration ...this reaction is essentially the reverse of photosynthesis! * organisms that can perform aerobic respiration only do so when there is oxygen present...otherwise, they carry out anaerobic respiration (fermentation) THE 2 PHASES OF AEROBIC RESPIRATION 1) The anaerobic phase: * the first step of aerobic respiration is GLYCOLYSIS (the breakdown of glucose)(REMEMBER: this step does not require OXYGEN!!!) *this step yields (gives) a net gain of 2 ATP 2) The aerobic phase: * here, pyruvic acid (now with oxygen available) is broken down slowly in a complex chain of events called the Krebs Cycle where hydrogen ions are kicked out * during this cycle, 34 more ATP are produced...for a net gain of 36 ATP that is from both steps combined" oxygen picks up the hydrogen and forms water... O2 + 4H ----> 2H2O * the carbon from the pyruvic acid is kicked out as carbon dioxide