Cellular Respiration - Weebly

12/7/2018Cellular RespirationHow do living things usechemical reactions to get energy from food?Version November 20171www.modelbasedbiology.comHow do we get our energy from food?www.modelbasedbiology.com1

12/7/2018The connection between food and energy We’ve figured out that we somehow getenergy from food and that it has to dowith chemical reactions where matter isrearranged.Draw an energy diagram that representsthe rearrangement of food in our bodiesin Doodle Box A.Remember to label INPUTS(reactants food) and OUTPUTS (products),and write what we know about them.3www.modelbasedbiology.comThe chemical reaction inside of us We know that we get energy from foodthrough some kind of chemical reaction.We know the reaction has differentreactants and products (molecules arerearranged) and that energy is released.But what are the reactants and products?What atoms are they made up of?What do we know or wonder about thespecific reaction in our bodies?4www.modelbasedbiology.com2

12/7/2018How do we get the energy from food?Hmmm.How do we actually get energy from food?EnergyLet’s explore a bit y.comFood is our fuel .INPUTS(gas & ?)USES(vroom‐vroom)OUTPUTS(emissions)How does a car get energy from it’s fuel?What’s the reaction?(Or at least, what is the reaction logy.com3

12/7/2018Food is essentially our fuel.We talk about: “Burning calories” “Burning carbs” “Burning Fat”But we are stilltrying to figure out:How do we getenergy from food?Does this help?www.modelbasedbiology.comLet’s see what burning (oxidizing) food looks like!DEMOwww.modelbasedbiology.com4

12/7/2018What makes something a fuel?What do these substances have in common in terms ofenergy?What do they have in common in terms of matter?Record your ideas in Doodle Box E.9www.modelbasedbiology.comWhat makes something a fuel?Paraffin (WAX):Heptane(gasoline)Methane(natural gas)PropaneFuelLots of Carbon-Hydrogen-Oxygen!COAL:What else do these fuels need inorder to burn (release their energy)?What is the other reactant whensomething burns?O2What else do WE need to take inbesides our fuel (food!)?WOOD:O2!So O2 is definitely one of thereactants in our energy- releasingreactions.www.modelbasedbiology.com5

12/7/2018What exactly is burning?ENERGYFUELWhat other reactant dowe need again? Recordin Doodle Box F.Following the conservation of matter, whatare the likely products? Record in Doodle F.(Do you see any products when stuff burns?)11www.modelbasedbiology.comWhat exactly is burning?ENERGYFUEL O2Record this definitionfor burning in Doodle F.CO2 H2OCO2 H2OCarbon fuel (C, H, some O) O2ENERGY12www.modelbasedbiology.com6

12/7/2018What happens when we eat food?CO2 H2OCarbon fuel (C, H, some O) O213ENERGYHow does our definition of fuel and burning fitour understanding of what might be happeningwith carbs, proteins and fats in our body?Write your ideas in Doodle Box G.What questions do we still have?Record these in Doodle Box G too.Be prepared to share out to the class.www.modelbasedbiology.comClass Driving QuestionWhat is the reaction in our cells andhow in the body is it the same as anddifferent from burning?Write this question in Doodle Box H.14www.modelbasedbiology.com7

12/7/2018Investigation:What is the connection betweenincreased energy demand (exercise) and athe rate of burning (output of CO2)?www.modelbasedbiology.comBurning for EnergyWe’ve seen that we produce more CO2 whenwe exercise.So there’s a connection between exercise andthe rate of the reaction that gives us energy.But is there a connection betweenexercise and matter? What happens toour mass when we exercise?www.modelbasedbiology.com8

12/7/2018www.modelbasedbiology.comWhat we’ve figured out so far FOOD O2And now we know that:FOOD is made ofproteins, fats andcarbohydrates.ENERGY for LIFECO2 H2OLet’s try to narrow it down. Which of these moleculesprovide our energy? In other words, which is our “fuel”?www.modelbasedbiology.com9

12/7/2018www.modelbasedbiology.comLet’s step back What happens to thathamburger or veggie burgerafter we eat it ?What is the burger made of ?absorbedintobloodstreamRecall what we knowabout the components offood.digestive tractWhat’shappening whileit’s in com10

12/7/2018FOODFatsProteinsCarbohydratesDigestion breaks them down to GLUCOSEFATTY ACID &GLYCEROLAMINO ACIDSFirst, breaks into its component polymers.Do you think it stops there?No, the “polymers” get broken into “monomers”.Then THOSE monomers are absorbed in to bloodstream.www.modelbasedbiology.comMatter and Molecules: Carbs, Fats, ProteinsNprotein(zoomed in on amino acid chain)carbohydratefat moleculeHCOwww.modelbasedbiology.com11

12/7/2018PolymersMonomersamino acidsprotein(zoomed in on amino acid chain)glucosecarbohydrate glycerolfat moleculefatty acidswww.modelbasedbiology.comRecord these ideas in Doodle Box K.amino acidsprotein(zoomed in on amino acid chain)glucosecarbohydrate glycerolfat moleculefatty acidswww.modelbasedbiology.com12

12/7/2018Which monomer is the fuel?Which one (or ones) do you think isour fuel? Why?amino acidsglucosefatty acids glycerolwww.modelbasedbiology.comWhat’s the carbon‐containing fuel?glucoseOur bodies work to supplyGLUCOSE to all of our cells,every minute of every day! People who have difficulty regulating the amount of glucosein their blood and the amount that gets into the cells have acondition called diabetes. Our brains in particular require a very consistent supply ofglucose. Muscles have a need for lots of glucose all at once, so theystore it right in the tissue. They even store extra oxygenwhich makes them red!www.modelbasedbiology.com13

12/7/2018The importance of glucose Our brains use about 50%of the energy we requireeach and every day!The Human BrainThe evolution of increased bloodsupply and delivery of glucose toour brains is thought to be a keystep in human evolution.It allowed our brains tobecome larger thanmost mammals (but weburn more energy!)www.modelbasedbiology.comThe importance of glucose When we exercise, we don’t eat as we do it.We also don’t have to eat right before weexercise So where is the fuel coming from in thatmoment when we are running, jumping, orswinging a bat?Complete the reading about glucose andexercise and answer the questions at the end.www.modelbasedbiology.com14

12/7/2018The importance of glucose When we exercise, our musclesand heart (a muscle!) increasetheir “demand” for glucose.MusclesWe actually store glucose in muscle!Why is muscle red?Glycogenglucose units!www.modelbasedbiology.comThe importance of glucose When we exercise, our musclesand heart (a muscle!) increasetheir “demand” for glucose.MusclesWe store oxygen in muscle too!Why is muscle red?An iron group “holds” the oxygen.Myoglobin(a protein)This is the same structure is seen inblood cells that carry oxygen!(hemoglobin protein)www.modelbasedbiology.com15

12/7/2018The importance of glucose www.modelbasedbiology.comWe have a reaction!C6 H12O6 6 O2“Cellular Respiration”Glucose and OxygenENERGY for LIFE6 CO2 6 H2OCarbon Dioxide and Waterwww.modelbasedbiology.com16

12/7/2018Where does cellular respiration happen?In our cells,in the MITOCHONDRIA.Nearly all cells have mitochondria,but muscle cells have tons ofmitochondria (so they can use allof that glucose and oxygen theyare storing)!www.modelbasedbiology.comBurning gives a lot of energy!CARBON FUEL O2LOTS OFENERGY!WaxWoodCO2 H2OCoalWhat form does the energy take in burning?(What evidence do we have for energy?)www.modelbasedbiology.com17

12/7/2018Burning FOOD gives a lot of energy!C6 H12O6 O2LOTS OFENERGY!glucoseCO2 H2OThe calories from glucose in a bowl of cereal is the same type ofenergy as we saw in the burning gummy bear demonstration! www.modelbasedbiology.comBurning FOOD gives a lot of energy!If we think that carbs give us this muchenergy, what’s the problem if this ishappening inside our cells? www.modelbasedbiology.com18

12/7/2018What is the problem with having areaction like this happen in a cell?In combustion reactions, the fuel molecules arerearranged all at once, in one big step, so all of theenergy is released at once!www.modelbasedbiology.comBreak it up!C6H12O6 6O2Many smallrearrangements,each releasing asmaller amount ofenergy!6CO2 6H2Owww.modelbasedbiology.com19

12/7/2018But wait The energy from burning fuel is released as heat and light.Can cells use HEAT to do the work of life?Some helps heat our bodies, yet most is lost to the environment.BUT cells can’t use heat to do work.How can a cell move energy from the mitochondria to where it’s needed?These problems are solved by a little molecule calledATPAdenosine TriphosphateThink of it as the transport molecule for energy in the cell!www.modelbasedbiology.comATP transports usable energy inside the cell!ATP is a molecule that starts as ADP.When it comes in contact with an energy-releasing reaction, it gets energized and transformsinto ATP. ADP ATPATP captures energy released when glucose is rearranged.This is the only kind of energy a cell can use directly to do work.ATP moves the energy from mitochondria to wherever it may be needed in the cell.www.modelbasedbiology.com20

12/7/2018ATP Structurewww.modelbasedbiology.comRemember: Releasing energy from food is a multi‐stepprocess. Each step re‐arranges the atoms,creates new molecules and releases someenergy.You are not responsible for knowing theenzymes involved in all of the step and theintermediate molecules that are built.www.modelbasedbiology.com21

12/7/2018Anaerobic vs. AerobicOxygen is the key but what’s thedifference?www.modelbasedbiology.comSome living things get usable energy fromfood (matter) without oxygen at all.They were likely the first to evolve. Theycan live of this relatively low ATP output.We still have the ability to do this, but thisis just part of the equation. (and a step inthe process you DO have to know)www.modelbasedbiology.com22

12/7/2018Fermentation ReactionsGlucoseYou get these two ATPwith or without oxygen.ATPATPPyruvate (2)TheHappensparty movesinto thethe CytosolMitochondriaWithout oxygen,you don’t get any more.If oxygen present, go toCellular RespirationFermentationIn HumanMuscle CellsFermentationIn YeastCarbonDioxide (2)Ethanol (2)Lactic Acid (2)www.modelbasedbiology.comFermentation ReactionsGlucoseYou get these two ATPwith or without oxygen.ATPATPPyruvate (2)FermentationIn HumanMuscle CellsATPATPATPATPATPATP ATP ATPATPATPATPATPATPATPATPATPATPATPATPATPATPATPATP ATP ATPATPATPATP ATPATPATPATPATPIf oxygen present, go toATPATPCellular RespirationFermentationIn YeastCarbonDioxide (2)Lactic Acid (2)Ethanol (2)www.modelbasedbiology.com23

12/7/2018Fermentation TypesLactic Acid FermentationProduces a 3‐carboncompound calledLACTIC ACID.www.modelbasedbiology.comFermentation TypesAlcoholic FermentationProduces a 2‐carboncompound calledETHYL ALCOHOL.www.modelbasedbiology.com24

12/7/2018www.modelbasedbiology.com Fermentation is an anaerobic process –happens in the absence of oxygen Cellular Reparation is an aerobic process –requires oxygenwww.modelbasedbiology.com25

12/7/2018OK Now What?If you don’t have enough oxygen, aerobicrespiration can’t occur, but fermentationcan.C6H12O6 6O26CO2 6H20www.modelbasedbiology.comOK Now What?If you have oxygen, aerobic respiration can occur.C6H12O6 6O26CO2 6H20A lot of Energy(ATP)www.modelbasedbiology.com26

12/7/2018ATP “captures” the energy from the burning of glucose!C6H12O6 6O2ATP x 2xThe 36 ATPmolecules are thenable to transportenergy about the cell!36Each small rearrangementreleases a small amount ofUSABLE energy to an ADPmolecule, transforming it toenergy-carrying ATP!In the rearrangement ofglucose and oxygen tocarbon dioxide and water,we produce 36 ATP thisway.ATP x 346CO2 6H2O 36 ATP in totalx36www.modelbasedbiology.comATP transports usable energy inside the cell.ADP is continually being made into ATP in ourmitochondria. ATP then delivers energy to other parts ofthe cell to do “work”.Then what happens to it?www.modelbasedbiology.com27