Survey
* Your assessment is very important for improving the workof artificial intelligence, which forms the content of this project
* Your assessment is very important for improving the workof artificial intelligence, which forms the content of this project
GCSE Biology Week 5: Cellular Respiration B2 2.1 Respiration releases energy B2 2.4 Aerobic respiration uses oxygen to release energy from glucose B2 2.9 Anaerobic respiration releases energy from glucose B2 2.10 Anaerobic respiration releases less energy than aerobic respiration B2 2.11 A build-up of lactic acid requires extra oxygen to break it down AlllivingcellscarryoutRespiration– EVEN Plants!(Theyphotosynthesize– whenits light,andrespirewhenitsdark!) Respirationisnotbreathing!Breathingis ventilation (breathinginandout)which actuallyprovidestheOxygen(O2) neededforaerobicrespiration. Respirationtakesplaceinthecytoplasm &Mitochondria (rememberwhen labellingyourcellsmitochondriaarethe organellesthatproduceenergy!) *sidenote– youdon’tneedto“revise” this– butitisusefultoknow… mitochondriaactuallyhaveinfolding’s (calledcristae)thatincreasetheirsurface area! Whatdoesanincreasedsurfacearedo? Itincreasestherateofdiffusion! Cellular Respiration: You need ENERGY to live. Energy comes from the digested chemicals from foods – respiration is the process that releases the energy. It is actually a process that occurs in all your CELLS in your body! It is the process of RELEASING ENERGY from GLUCOSE. Respiration is NOT BREATHING! (ventilation) There are 2 types of RESPIRATION: 1. Aerobic – requires Oxygen! Aerobic means “with O2” and aerobic respiration occurs when there is lots of O2 present 2. Anaerobic – does not require Oxygen! 2. Aerobic respiration releases more ENERGY per molecule of GLUCOSE than anaerobic respiration. REMEMBER: RESPIRATION is the process of RELEASING ENERGY from GLUCOSE Mostly you are using AEROBIC RESPIRATION: turning GLUCOSE from your food, and O2 from your LUNGS into CARBON DIOXIDE and WATER. Releasing LOTS of ENERGY in the process! You MUST REMEMBER THIS EQUATION! C6H12O6 + O2 à CO2 + H2O + ENERGY (ATP) AerobicRespirationRecap. Aerobicrespiration usesoxygen (O2)andthemostefficientwayofgetting energy (ATP)fromglucose. Infact,ifwecomparetoanaerobicrespiration,wefindthatforevery1molecule ofGlucose(C6H12O6)aerobicrespiration (withO2)provides20timesmore energythanwouldbeproducedanaerobically(withoutO2)! BloodtransportsO2 andGlucose(C6H12O6)(Food)toourcells,whereenzymes (biologicalcatalyst’s)speeduptheprocessofreleasingenergy. SoWhatistheequationforRespiration? Remember,respirationusesoxygen andfood(glucose)togetenergy!So,wehave:Oxygen+Glucose=Energy Now,asaresultofrespirationcarbondioxide (CO2)isalsoproduced(ourwasteproduct) andsomewaterisproduced(H2O).So,we mustalsoaddtheseproductstoourequation. MakingthefullRespirationequationlooklikethis: Oxygen+Glucoseà Energy+Carbondioxide+Water Nowweshouldalsobeabletowritethis out“Chemically”,So… O2 +C6H12O6 à Energy(ATP)+CO2 +H2O Oxygen (O2)andGlucose (C6H12O6)aretransportedinthe bloodstream(O2 yougetfromventilation– breathingitin) andGlucose(C6H12O6)comesfromyourdiet. Energy (ATP– adenosinetriphosphatethe energymolecule)isusedformanylifeprocesses. Carbondioxide (CO2)isthewasteproduct,andis returnedviathebloodstreamtoyourlungs (ventilation– Breathingitout). Water isalsoabyproductofrespiration,whichis thenlostassweat;someinyoururine;andsome asmoistbreath(ventilation– youbreathout somewater). Thisiswhatisgoingon 1. ATP is the ‘ENERGY CURRENCY’ of living things… 2. ATP is a small molecule that is easily transported around cells. It carries the ENERGY released during RESPIRATION to the places where ENERGY is NEEDED 3. Energy released from both aerobic and anaerobic respiration is used to make ATP The energy released by respiration is used to make ATP (adenosine triphosphate) Your muscles require energy (ATP) from respiration to contract. When you exercise some of your muscles contract more often, and so need more ENERGY! This ENERGY comes from increased respiration! MUSCLES NEED ATP This increase means you need to get more O2 and GLUCOSE into the cells. So… your BREATHING RATE INCREASES to get more O2 into the… Blood. BREATHING RATE INCREASES! Your HEART RATE INCREASES to get GLUCOSE and OXYGENATED BLOOD around the body supplying your muscles quickly, and removes CO2 quickly at the same time! HEART RATE INCREASES How much you RESPIRE is dependent upon what you are doing! e.g. you respire more when doing exercise… ANAEROBIC RESPIRATION: When you do vigorous exercise your body cannot supply enough O2 to your muscles using anaerobic respiration – even though your Heart rate and breathing rate increase as a much as possible! Does NOT use O2 at all! So, your muscles start to respire without O2 – they respire anaerobically. (in addition to aerobic) ANAEROBIC simply means ‘without O2’. It is NOT the best way to use GLUCOSE because it releases much LESS ENERGY. ANAEROBIC = ‘without O2’. During anaerobic respiration GLUCOSE is only PARTIALLY broken down and LACTIC ACID is also produced! You MUST REMEMBER THIS EQUATION! GLUCOSE à LACTIC ACID (+ ENERGY RELEASED) The ADVANTAGE is that you can continue using your muscles! However… The LACTIC ACID produced can build up in the muscles. Oxygen Dept This is why you continue to have an increased BREATHING RATE for a while after you have stopped Exercising. After resorting to anaerobic respiration, your muscles have an O2 DEPT. This is the amount of extra O2 required to break down the built up LACTIC ACID. The Lactic acid is BROKEN DOWN in your MUSCLES and in your LIVER… …so your HEART RATE has to remain HIGH to carry The EXTRA required to Break the LACTIC ACID down. AnaerobicRespirationRecap. Anaerobic=withoutoxygen(O2) Sometimesweneedtoproduceenergyveryquickly– i.e.explosiveactivitieslikesprinting. So,anaerobicrespirationtakesplacewhenthereisn’tenoughoxygen(O2)availabletosupplythe body(e.g.muscles)withtheO2 requiredfor‘normal’aerobicrespiration. Anaerobicrespirationisveryusefulinemergencies!(thinkFightorFlight– whichwe’llcover whenwecoverthenervoussystem).Onthewhole,anaerobicrespirationdoesnotproducesas muchenergyasaerobicrespiration(about20timeslessremember)butisveryrapid.Thisis becauseglucose(C6H12O6)isonlypartiallybrokendown. Whenglucoseisonlypartiallybrokendownanotherwasteproductismade– Lacticacid! Wecanshowthiswithour“wordequation”forAnaerobicrespiration: Glucoseà Lacticacid+Energy(ATP) Thisiswhat’sisgoingon… Glucose (C6H12O6) isdeliveredtothecells(muscles)viathebloodstream. Lacticacid isawasteproduct(thatbuildsupinthemuscles– andleadsto “cramp”) Energy(ATP) onlyasmallamountisproduced– butisenoughforshortterm/ explosiveactivity. Abuildupoflacticacidrequiresextra oxygentobreakitdown. Asyouincreasephysicalactivity (exercise)yourbreathing (ventilation)ratewillalso increase.Thisisbecauseyour cells(yourbody)needsthe extraoxygeninordertorespire (carryoutaerobicrespiration) efficiently,andprovidethe extraenergyneeded. So,asyourbreathing(ventilation) rateincreaseslargeramountsofO2 entersyourbloodstream,yourheart mustaccommodatebyspeedingup, andsupplyingthisoxygenated bloodtoallthecellsandtissues thatrequireit. Thequickeryoubreathe,thequickeryourheartrate! ThissuppliesO2 whereneeded,butastherateof respirationisincreasedsoarethewasteproducts. Todealwiththistherateofdiffusionof(O2 andCO2)atthe Alveoli(inthelungs)andattheMusclecellsincreases. (Rememberthesegasesaremovingdowntheir concentrationgradients). However,thisincreaseddiffusionandsupplyofO2 /removalof waste(CarbondioxideCO2)cannotgoonindefinitely.Asyou performvigorousexercises(likeInsanity,Tapoutorsprintingaway fromcrocodiles)yourbodyisunabletosupplyalltheO2 needed/ quicklyenough. So,yourcellsstarttorespireanaerobically!(but rememberthiscomeswithitsownwasteproduct– Lacticacid).Theupsideisthatyoucancarryon exercisingandusingthosemusclesalittlebitlonger! Becauseyourbreathingrate hasincreasedandyouhave employedanaerobic respirationyouwillbe“out ofbreath”!Thisiscalled oxygendept. Afterallthiscrazyexerciseyou’ll mostlikelybe“outofbreath”! So,youwillhavetorepaytheO2dept.– which iswhyyoubreatheheavilyfollowingvigorous exercise.Thisisgiveaspecialacronym: EPOC Exercise/post-exerciseoxygenconsumption. Thismeansyou’llcontinuetobreathe heavily– takinginlotsofO2 intothe bloodstream,supplyingthecellsand muscles.Yourheartratewillremainhigh todealwiththisextraO2demand.The extraO2 isusedtoconvertLacticacidinto CO2 andH2O– whereyoubreathethem out(andsweatthemout– H2O). *Whenwecoverthecirculatorysystems andrespiratorysystemswewill investigatetheeffectsofexercise,so, howcellularrespiration– i.e.howcells gettheirenergyandutiliseitwillbe revisited. You will also need to remember to connect cellular respiration with Diffusion and active transport! Question time…