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CELLULAR RESPIRATION All living organisms need energy.

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Presentation on theme: "CELLULAR RESPIRATION All living organisms need energy."— Presentation transcript:

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2 CELLULAR RESPIRATION All living organisms need energy

3 Cellular Respiration Harvesting Chemical Energy ATP

4 INTRODUCTION TO CELLULAR RESPIRATION Introduction: All living organisms need energy Respiration: the life process by which organisms convert the chemical energy stored in food to a form of energy more easily utilized by the cell Process of Cell Respiration: a biochemical process used by cells to release energy from organic molecules (food) such as glucose ~this energy is stored in the molecule ATP ~ ATP = adenosine triphosphate or A~P~P~P ~ the process is controlled by enzymes

5 Harvesting energy stored in food Cellular respiration – breaking down food to produce ATP in mitochondria using oxygen – “aerobic” respiration – usually digesting glucose but could be other sugars, fats, or proteins C 6 H 12 O 6 6O 2 ATP6CO 2 6H 2 O  + ++ glucose + oxygen  energy + carbon + water dioxide O2O2 food ATP

6 What do we need to make energy? The “Furnace” for making energy – mitochondria Fuel – food: carbohydrates, fats, proteins Helpers – oxygen – enzymes Product – ATP Waste products – carbon dioxide then used by plants – water O2O2 food ATP Make ATP! Make ATP! All I do all day… And no one even notices! enzymes CO 2 H2OH2O

7 Mitochondria are everywhere!! animal cells plant cells

8 Can’t store ATP  too unstable  only used in cell that produces it  only short term energy storage  carbohydrates & fats are long term energy storage Using ATP to do work? A working muscle recycles over 10 million ATPs per second ATP ADP work Whoa! Pass me the glucose & oxygen! Adenosine DiPhosphate Adenosine TriPhosphate

9 make energy A Body’s Energy Budget eat food synthesis (building) energy needed even at rest activity temperature control { growth reproduction repair { storage glycogen (animal starch) fat { ATP 1 2 3

10 Aerobic Cellular Respiration Aerobic = with oxygen Occurs in the mitochondria The use of oxygen releases more energy per glucose molecule than anaerobic = without oxygen Uses oxygen but releases carbon dioxide and water SUMMARY EQUATION:

11 Breathing and cellular respiration are closely related Bloodstream Lungs O2 CO2 O2 BREATHING Muscle cells carrying out CELLULAR RESPIRATION Sugar + O2  ATP + CO2 + H2O

12 Oxidation-Reduction Reactions Redox for short Oxidation= loss of electrons (or H+) Reduction= gain of electrons (or H+) OIL RIG: Oil = Oxidation is loss Rig = Reduction is gain ~chemical reaction which involve a partial or complete transfer of electrons form one reactant to another ~ a coupled reaction Cell Respiration is a redox process that transfers hydrogen form sugar to oxygen oxidation C 6 H 12 O 6 + 6O 2 --  6CO 2 + 6H 2 O + ATP( energy) reduction

13 Hydrogen carriers such as NAD + shuttle electrons in redox reactions Enzymes remove electrons from glucose molecules and transfer them to a coenzyme / electron carriers[ NADH & FADH 2 ]

14 Redox reactions release energy when electrons “fall” from a hydrogen carrier to highly electronegative oxygen NADH ( & FADH2) delivers electrons to a series of electron carriers in an electron transport chain – As electrons move from carrier to carrier, their energy is released in small quantities Energy released and now available for making ATP ELECTRON CARRIERS of the electron transport chain

15 STAGES OF CELLULAR RESPIRATION Respiration occurs in three main stages GLYCOLYSISKREBS CYCLE ELECTRON TRANSPORT CHAIN High-energy electrons carried by NADH Mitochondrion Cytoplasmic fluid

16 1. Glycolysis: [Glyco=sweet, sugar lysis = to split] ~process in which one molecule of glucose is broken in half, producing 2 molecules of pyruvic acid, a 3-carbon compound ~ takes place in cytoplasm ~ makes 2 ATP {part of anaerobic respiration too] ~NO OXYGEN NEEDED ~ 2 molecules of NADH are formed Glucose Pyruvic acid

17 2. Krebs Cycle Each pyruvic acid molecule is broken down to form CO 2 and a two-carbon acetyl group, which enters the Krebs cycle [Transition phase] The Krebs cycle completes the oxidation of organic fuel, generating many NADH and FADH 2 molecules 2 turns per glucose molecule Occurs in mitochondria Produces 2 ATP 6 NADH & 2 FADH 2 KREBS CYCLE Acetyl CoA CO2

18 3. Electron Transport Chain In the electron transport chain, the carrier molecules NADH and FADH 2 give up electrons that pass through a series of reactions. Oxygen is the final electron acceptor forming water. This sets up a H+ (proton) gradient Allow the protons to flow through ATP synthase which synthesizes ATP (ADP + Pi = ATP) Produces 32 ATP Occurs in the inner mitochondrial membrane the electron transport chain adds 32 ATP molecules

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20 What if oxygen is missing? No oxygen available = can’t complete aerobic respiration Anaerobic respiration – also known as fermentation alcohol fermentation lactic acid fermentation – no oxygen or no mitochondria (bacteria) – can only make very little ATP – large animals cannot survive O2O2 yeast bacteria

21 Fermentation is an anaerobic alternative to aerobic respiration Process operates by means of chemical reactions catalyzed by enzymes in cytoplasm of cell Primary mode of energy production for some bacteria and fungi (yeast) use glycolysis alone to produce small amounts of ATP Important in production of foods such as cheese, buttermilk, yogurt, alcohol, (wine/beer) and bread 2 types: 1. alcohol & 2. lactic acid

22 Anaerobic Respiration Fermentation – alcohol fermentation yeast – glucose  ATP + CO 2 + alcohol – make beer, wine, bread – lactic acid fermentation bacteria, animals – glucose  ATP + lactic acid – bacteria make yogurt – animals feel muscle fatigue O2O2 Tastes good… but not enough energy for me!

23 Alcoholic Fermentation glucose -> pyruvic acid-> 2 ethyl alcohol + 2 CO 2 2ATP GLYCOLYSIS FERMENTATION

24 Lactic Acid Fermentation Glucose->pyruvic acid -> 2 lactic acid 2ATP GLYCOLYSIS FERMENTATION ~ used to make cheese and yogurt ~ in humans during strenuous exercise not enough oxygen from blood “oxygen debt” ~ lactic acid accumulates in muscle; leads to fatigue and pain Will be converted back to pyruvic acid in liver Both types a of fermentation are considered inefficient, only produce 2ATP from glycolysis

25 Cells use many kinds of organic molecules as fuel for cellular respiration Polysaccharides Fats Proteins Sugars Cellular respiration

26 Comparing Cellular Respiration & Photosynthesis Cell RespirationPhotosynthesis


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