Agenda. Cellular Respiration: A 3 part story. ph Cellular Respiration (aerobic) Anaerobic Respiration

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1 Agenda ph ellular Respiration (aerobic) Glycolysis Krebs ycle Electron Transport hain Anaerobic Respiration ph Our friend, the water molecule In a beaker of water, a very small number of water molecules may dissociate Dissociate: to break apart into ions What ions might we get? H O H + and OH - (ions) H + OH - ph ph is a measure of the amount of ions in solution ph The ph scale ranges from 0 to 14 ph 7 is called neutral At neutral ph, the amount of equals the amount of OHpH An AID is defined as a compound that donates to solution Hl (will dissociate almost completely, donating lots of to an aqueous solution ellular Respiration: A 3 part story A BASE is defined as a compound that accepts from solution Or donates OH- which then accepts 1

Glycolysis: the splitting of sugar First step in cellular respiration Occurs in the cytoplasm The enzymes involved are dissolved in cytoplasm!

2 Glycolysis: the splitting of sugar First step in cellular respiration Occurs in the cytoplasm The enzymes involved are dissolved in cytoplasm! INUT: glucose, a 6 carbon sugar Small amount of added to start reaction OUTUT: molecules of pyruvic acid (a 3 carbon molecule) small amount of NADH! yruvic Acid NADH Glycolysis splits a six-carbon glucose into threcarbon molecules AD Glucose is first energized with a phosphate. It has become momentarily less stable, energized. Glycolysis splits a six-carbon glucose into threcarbon molecules Small amount of energy INUT A high-energy 6 carbon, glucoslike molecule AD enzyme Glycolysis splits a six-carbon glucose into threcarbon molecules Small amount of energy INUT AD enzyme What is the cab carrying? NADH yruvic Acid YIELDS: NADH Glycolysis Occurs in the ytosol and does not require oxygen! Glycolysis generates a small amount of Glycolysis yruvic Acid YIELDS: NADH Direct phosphate transfer, enzyme mediated

3 Glycolysis generates NADH The book s version NADH What is meant by a high Later! energy electron? If an electron was swiped or transferred to NADH from glucose, what happened to glucose during glycolysis? Was it oxidized or reduced? Glucose yruvic acid High Energy Electrons in the form of NADH and FADH ellular Respiration NAD+ reduced NAD + + e H +!NADH FADH art : Krebs ycle art : Krebs ycle Where is this occuring? What is a cycle? Scary picture! Focus on outputs!! = 6 4 3

art : Krebs ycle NUMEROUS OXIDATION STES 6 arbon molecule is oxidized to molecules of O 6 art : Krebs ycle Oxidiation steps produce energy in the form of, NADH, FADH And the starting material (4

4 art : Krebs ycle NUMEROUS OXIDATION STES 6 arbon molecule is oxidized to molecules of O 6 art : Krebs ycle Oxidiation steps produce energy in the form of, NADH, FADH And the starting material (4 carbon molecule) is regenerated 4 Where are the cabs (with e - s) going?? NADH and FADH shuttle high energy electrons to an Electron Transport hain art 3: Electron Transport hain Where is this located, EXATLY?? What molecule sits at the bottom of the chain? Hint: the molecule at the bottom is waiting, and is very hungry for electrons Electron Transport hain in the Inner Mitochondrial Membrane? 4

5 OXYGEN Why is oxygen so important for cellular respiration? What function does the oxygen we BREATHE in have in this process? High energy electrons When high energy electrons are obtained by a protein, the protein may become energized These energized proteins have the capacity to do work! The work they will do? Transport against its concentration gradient I m feeling low on energy. I couldn t possibly do any WORK Before receiving I m energized, and ready to do some WORK AFTER receiving Assorted ions Assorted ions As electrons are passed down the ET, is pumped into the intermembrane space The work that is done is the pumping of ions across the inner mitochondrial membrane AGAINST a concentration gradient! 5

Synthase This cellular work, has set up a gradient across the inner

membrane space) do the ions want to diffuse?

diffuses through Synthase, a membrane protein that functions like our

htm Synthase is a mini-machine! http://protist.biology.washington.

mov Synthase captures the kinetic energy of diffusion, and transforms it

6 Synthase This cellular work, has set up a gradient across the inner mitochondrial membrane Which way (into the matrix, or into the inner membrane space) do the ions want to diffuse? The hydrogen ions will diffuse (rapidly) down their concentration gradient diffuses through Synthase, a membrane protein that functions like our paddle wheel htm Synthase is a mini-machine! 00/movies/cartoonsynthase.mov Synthase captures the kinetic energy of diffusion, and transforms it to synthesize from AD and. MOVIE TIME Energetic Summary of ellular Respiration an we generate under anaerobic conditions? How? Aerobic= oxygen present Anaerobic= without oxygen 6

Does glycolysis require oxygen? Krebs ycle Does glycolysis produce?

Without oxygen, NADH cannot drop off its high energy electrons at the

electron carrier) fills up Anaerobic Respiration: Lactic Acid

electrons to alternate substrates Why do we continue to breath heavily

Anaerobic Respiration: Alcohol Fermentation Aerobic cellular

7 Does glycolysis require oxygen? Krebs ycle Does glycolysis produce? If so, how much? Without oxygen, NADH cannot drop off its high energy electrons at the ET Since oxygen is not pulling electrons down the ET, NADH (the electron carrier) fills up Anaerobic Respiration: Lactic Acid Fermentation In the absence of oxygen, NADH donates its high energy electrons to alternate substrates Why do we continue to breath heavily even after we ve STOED exerting ourselves? Anaerobic Respiration: Alcohol Fermentation Aerobic cellular respiration utilizes OXYGEN as the final electron acceptor Anaerobic Respiration Are you thankful for yeast now?? Anaerobic respiration can occur with an alternate electron acceptor! 7

8 Evolutionary Implications of Anaerobic Respiration Glycolysis is the most widespread metabolic pathway on Earth Glycolysis evolved very early eople can t live on glucose alone!! OUT? 3.5 bya= bacterial fossils.7 bya= O accumulates Does glycolysis require membrane bound organelles? Eukaryotic cells?? arbon fuel can come from macromolecules other than glucose Food cyanide olysaccharides Fats roteins Sugars Glycerol Fatty acids Amino acids Glycolysis Acetyl- oa Krebs ycle Amino groups Electron Transport Why is cyanide poisonous? How does cyanide actually KILL people, at the molecular level?? 8

Respiration. Respiration. How Cells Harvest Energy. Chapter 7

Respiration. Respiration. How Cells Harvest Energy. Chapter 7 How Cells Harvest Energy Chapter 7 Respiration Organisms can be classified based on how they obtain energy: autotrophs: are able to produce their own organic molecules through photosynthesis heterotrophs: