Ec5d5a25-b30b-45e6-be29-9371ec8453ec%2FRespiration
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School
Langley High**We aren't endorsed by this school
Course
BIO 111
Subject
Biology
Date
Jan 14, 2025
Pages
7
Uploaded by EarlMetalAardvark29
Respiration1RespirationCellular respirationGlucose's carbon-hydrogen bonds can be broken to release energy that is used to make ATP by chemiosmosisGlycolysisdescribe where glycolysis occurs in the cell :Cytoplasmdescribe what kind of reaction glycolysis is :→ anaerobic processStages of Glycolysisphosphorylation 2 ATP molecules release two phosphates which react with glucose to form hexose biphosphatelysis : destabilisation of hexose biphosphate to form 2 triose phosphatesphosphorylation : another phosphate group added to each triose phosphate from phosphate ions in cytoplasmdehydrogenation : oxidation of 2 triose bi-phosphates by dehydrogenation to form 2 pyruvate.formation : formation of 2 reduced NAD , coenzyme NAD accepts removed hydrogen. Formation of 4 ATP by phosphate transfer from triose biphosphate to ADP.
Respiration2After glycolysis :reduced NAD is used in a later stage to synthesise more ATPProducts formed in glycoysis 2 Reduced NAD 2 ATP [overall net ATP yield as 2 ATP used to start glycolysis and 4 ATP made in end - so 422 ATP (net yield) ] 2 Pyruvatedescribe what is meant by “substrate level phosphorylationˮ .formation of ATP without involvement of electron transport chainLinking glycolysis and the Krebs cycleStructure of the mitochondria and the processes that take place :
Respiration3Link reaction / Oxidative decarboxylationthis is the first step in aerobic respiration that links anaerobic glycolysis in the cytoplasms to the aerobic steps of respiration that occurs in mitochondriaStages of the link creation / oxidative decarboxylation pyruvate enters mitochondrial matrix by active transport via specific carrier proteinsoxidative decarboxylation of pyruvate , removal of CO2 and Hydrogen (oxidation)CO2 diffuses way and is removed formation of NADH (reduced) by NAD accepting removed hydrogen atomtwo-carbon acetyl group bound by coenzyme A , forming Acetyl CoA which delivers acetyl group to Krebs cycleNADH used in oxidative phosphorylation for atp synthesisAfter link reaction NADH used in oxidative phosphorylation for ATP synthesisAcetyl CoA delivers acetyl group to Krebs cycle
Respiration4The Krebs cycle :what happens after the link reaction : hydrogen released are picked up by coenzymes NAD and FAD , Reducing them. They are then used to produce large amounts of ATP by chemisomosisName the place in the cell where the Krebs cycle takes place :mitochondrial matrixDescribe what happens at each complete cycle of the Krebs cycle :the breakdown of an acetyl groupStages of the Krebs cycleAcetyl CoA delivers acetyl group to Krebs cycle . The 2-carbon acetylene group combines with 4-carbon oxaloacetate form 6-carbon citratedecarboxylation and dehydrogenation of citrate molecules produces 1 NADH CO2 . 5-carbon compound made.Further decarboxylation and dehydrogenation of 5-carbon compound , regenerating oxaloacetateMore CO2 , 2 more reduced NADs and one reduced FAD is produced. Production of ATP by substrate level phosphorylationthe importance of coenzymes in respirationDescribe the role of coenzymes in respirationrequired to transfer protons , electrons and functional groups between many enzyme catalysed reactions , unable to function without them.examples of coenzymes in respirationNAD and FAD released by breakdown of glucose in respirationDescribe the differences between two named coenzymes , NAD and FAD NAD takes part in all stages of cellular respiration but FAD only accepts hydrogens in Krebs cycleNAD accepts 1 hydrogen but FAD accepts 2 hydrogenreduced NAD oxidised at start of ETC which relies protons and electors while reduced FAD is oxidised along the chainreduced NAD results in formation of 3 ATP but reduced FAD results in formation of 2 ATP
Respiration5Oxidative PhosphorylationAfter the Krebs cycle :Hydrogen atoms collected by coenzymes NAD and FAD are delivered to ETC in cristaes membrane of mithochondriaStages of Oxidative PhosphorylationH atoms are released from reduced NAD and FAD as they're oxidised to NAD and FAD. The H atoms split into protons and electrons.The electrons move along the electron transport chain, losing energy at each carrier.This energy is used by electron carriers to pump protons from the mitochondrial matrix into the intermembrane space.The concentration of protons is now higher in the intermembrane space than in the mitochondrial matrix - this forms an electrochemical gradient.Protons move down the electrochemical gradient, back into the mitochondrial matrix, via ATP synthase.This movement rives the synthesis of ATP from ADP and inorganic phosphate. This process of ATP production is called chemiosmosis.In mitochondrial matrix, at the end of the transport chain, the protons, electrons and oxygen combine to form water. Oxygen is said to be the final electron acceptor
Respiration6Substrate level phosphorylationthe production of ATP by transfer of phosphate group from short-lived , highly reactive intermediate i.e , creatine phosphatewhy does substrate-level phosphorylation differ from oxidative phosphorylationsubstrate level phosphorylation couples the flow of protons down the electrochemical gradient through ATP synthase to phosphorylation of ADP to make ATP.Anaerobic respirationresults in synthesis of smaller amounts of ATP due to absence of/ less oxygen .obligate anaerobes → can't survive in presence of O2 , almost all are prokaryotes and some fungifacultative anaerobes → make ATP by aerobic respiration if O2 is present , but can switch to anaerobic respiration if O2 is absent .i.e yeast.obligate aerobes → only makes ATP in presence of O2 like mammals. They supplement ATP supplies by using anaerobic respiration in addition to aerobic respiration when O2 concentration is low.Fermentationa form of anaerobic respiration where complex organic compounds are broken down into simpler inorganic compound without use of O2 or involvement of electron transport chainproduces less ATP which is synthesised by substrate-level phosphorylation alonewhen there is no oxygen to act as final electron acceptor at end of ETC in oxidative phosphorylation , electron flow stops so synthesis of ATP by chemiosmosis stopsas electron flow along ETC has stopped , NADH and FADH cannot be oxidised as electrons have nowhere to go.so NAD anf FAD can't be regerneated and so the decarboxylation and oxidation of pyruvate and the Krebs cycle stops as there is no co enzymes to accept the removed hydrogen atoms
Respiration7glyolysis also stops due to lack of NAD , but fermentation prevents this .what happens in anaerobic respiration and when there is no oxygen to the formation of ATP when there is no oxygen to act as final electron acceptor at end of ETC in oxidative phosphorylation , electron flow stops so synthesis of ATP by chemiosmosis stopsLactate fermentation in mammals :pyruvate acts as hydrogen acceptor , taking hydrogen from reduced NAD catalysed by lactate dehydrogenase pyruvate converted into lactate and NAD regeneratedcan be used to keep glycolysis going so small amount of ATP still madelactic acid is removed from muscles and taken to liver where it can be converted back into glucosewhy lactate fermentation cannot occur indefinitely:reduced amount of ATP made is not enough to maintain vital processes for long period of timebuild up of lactic acid causes fall in pH , leading to proteins denaturing . Enzymes in respiration will cease to function at low pHAlcoholic fermentation in yeastpyruvate converted to ethanal , catalysed by pyruvate decarboxylaseethanal accepts hydrogen atom from reduced NAD, becoming ehtanolregenerated NAD can then continue to act as coenzyme and glycolysis can continuethis long-term process can happen indefinitely without oxygenethanol is toxic waste product to yeast cells and are unable to survive if accumulatedRespiratory Substrates→ difference in energy values between substancesRQ amount of CO2 produced / amount of O2 consumed and taken inrelative energy valuescarbohydrates 1.0Protein 0.9lipids 0.7