2Cellular RespirationHave you ever wondered why exactly you need to breathe? What happens when you stop breathing?
3Cellular respiration is the set of the metabolic reactions and processes that take place in the cells of organisms to convert biochemical energy from nutrients into adenosine triphosphate (ATP), and then release waste products.Mitochondria!
4C6H12O6 + 6O2 -->6 CO2 + 6H2O + 36 ATP C6H12O6 + 6O2 -->6 CO2 + 6H2O + 36 ATP
5Heterotrophs Autotrophs How are they connected? making energy & organic molecules from ingesting organic moleculesglucose + oxygen carbon + water + energydioxideC6H12O66O26CO26H2OATP+oxidation = exergonicAutotrophsWhere’s the ATP?making energy & organic molecules from light energySo, in effect, photosynthesis is respiration run backwards powered by light.Cellular Respirationoxidize C6H12O6 CO2 & produce H2Ofall of electrons downhill to O2exergonicPhotosynthesisreduce CO2 C6H12O6 & produce O2boost electrons uphill by splitting H2Oendergonic+ water + energy glucose + oxygencarbondioxide6CO26H2OC6H12O66O2lightenergy+reduction = endergonic
6O2 or no O2Aerobic Respiration: requires oxygen (air) (breathing) Anaerobic Respiration: does not need oxygen (no air) (breathing)
7AEROBIC = with oxygen, occurs in the presence of oxygen - in mitochondira Without oxygen, another path is taken ....this path is called fermentation, or Anaerobic = without oxygen, in cytosol
82. Kreb's Cycle (Citric Acid Cycle) 3. Electron Transport Chain There are three stages1. Glycolysis2. Kreb's Cycle (Citric Acid Cycle)3. Electron Transport Chain
9GLYCOLYSIScan occur without oxygenGLYCOLYSIS = "glyco - lysis " is the splitting of a 6 carbon glucose into two pyruvates, each having 3 carbonsnet yield of 2 ATP per glucose molecule net yield of 2 NADH per glucose molecule
10What does cellular respiration produce? Does it need light? QODWhat does cellular respiration produce?Does it need light?What does anaerobic mean?What does aerobic mean?What is the equation for cellular respirations?
11Stage 1: Glycolysis: Products: 2 ATP 2 NADH 2 Pyruvic Acids Anaerobic = no O2 neededOccurs in cytoplasmOccurs in all organismsNet of 2ATPProducts:2 ATP2 NADH2 Pyruvic Acids
12Stage 1: Glycolysis: Products: 2 ATP 2 NADH 2 Pyruvic Acids Anaerobic = no O2 neededOccurs in cytoplasmOccurs in all organismsNet of 2ATPProducts:2 ATP2 NADH2 Pyruvic Acids
13Equation for Cellular Respiration: oxidation & reduction REDOX reactions in respirationrelease energy as breakdown organic moleculesbreak C-C bondsstrip off electrons from C-H bonds by removing H atomsC6H12O6 CO2 = the fuel has been oxidizedelectrons attracted to more electronegative atomsin biology, the most electronegative atom?O2 H2O = oxygen has been reducedcouple REDOX reactions & use the released energy to synthesize ATP*Need mitochondria and enzymes to make this happen!O2 is 2 oxygen atoms both looking for electronsLIGHT FIRE ==> oxidationRELEASING ENERGYBut too fast for a biological systemC6H12O66O26CO26H2O36ATP+oxidationreductionor 38
152. Citric Acid or Krebs Cycle Hans KrebsIt is not necessary to know the individual stepsoccur ONLY if oxygen is present and the cell has mitochondria.In this stage of cellular respiration, the oxidation of glucose to CO2 is completed. (this is why we exhale carbon dioxide)
16Acetyl CoA enters Krebs cycle Pre Krebs: The pyruvic acid (C3) loses a C to CO2 and use a H + to form NADH and becomes Acetyl Co-A (C2).Simple put: Pyruvate is converted to Acetly CoAreleases 2 CO2reduces 2 NAD 2 NADH (moves e-)produces 2 acetyl CoAAcetyl CoA enters Krebs cycle
17Products (per glucose) Krebs Cycle OverviewCitric acidAerobicOccurs in the matrix (inner compartment)Products (per glucose)2 ATP6 CO28 NADH2 FADH2.These energy carriers now enter the electron transport chain (ETC).
18Count the C & electron carriers! pyruvateacetyl CoA3C2CNADHNADHcitrate4C6C4C6Creduction of electron carriersThis happens twice for each glucose moleculeCO2Everytime the carbons are oxidized, an NAD+ is being reduced.But wait…where’s all the ATP??NADHx25C4CFADH2CO24C4CNADHATP
193. Electron Transport System: Oxidative Phosphorylation: process in which ATP is formed as a result of the transfer of electrons from NADH or FADH 2 to O 2 by a series of electron carriers.As opposed to photophosphorylation….a) consists of a series of enzymes on the inner mitochondrial membraneb) electrons are released from NADH and from FADH2 and as they are passed along the series of enzymes, they give up energy which is used to fuel a process called chemiosmosiswhich drives ATP synthesisETC
20Does this picture look familiar? You've seen this before in photosynthesis.Products:34 ATPAnimation of the ETC McGraw Hill Animation
22Cytochrome c oxidase complex FADH NADH CoenzymeQNAD dehydrogenaseBc complexCoenzyme cCytochrome c oxidase complexFADHNADHADPATP synthaseMcGraw Hill Animation
23FADH NADH H2O McGraw Hill Animation ADP NAD dehydrogenase Coenzyme Q Bc complexCoenzyme cCytochrome c oxidase complexFADHNADHH2OADPATP synthaseMcGraw Hill Animation
24Cytochrome c oxidase complex FADH NADH CoenzymeQNAD dehydrogenaseBc complexCoenzyme cCytochrome c oxidase complexFADHNADHH2OADPATP synthaseMcGraw Hill Animation
25-net yield of 32 or 34 ATP per glucose molecule - 6 H2O are formed when the electrons unite with O2* at the end of electron transport chain. * We breath because we need oxygen as the final electron acceptor! The resulting ATP is able to leave the mitochondria by the ATP transport protein in the membrane. It goes to wherever it is needed in the cell.Without oxygen to serve as the final electron acceptor, the process shuts down.
26Breakdown of One Glucose Molecule Calculations from each:NADH= 2 or 3 ATP can be madeFADH2= 2 ATP can be made1. Glycolysis – Produces:2 ATP 2 NADH2. Krebs Cycle (including “pre-Kreb’s”) - Produces:2 ATP 8 NADH FADH2Total: 4ATP 10 NADH FADH23. ETC - Produces: x x 230 ATP ATP = 34 ATPTotal: 4ATP + 34 ATP + a grand total of 38 ATP !Theoretical YieldDetermining the exact yield of ATP for aerobic respiration is difficult for a number of reasons.- bacteria may differ in their carriers in the ETC- the number of ATP generated per reduced NADH or FADH2 is not always a whole number.For every pair of electrons transported to the electron transport chain by a molecule of NADH, between 2 and 3 ATP are generated. For each pair of electrons transferred by FADH2, between 1 and 2 ATP are generated.For simplicity, however, we look at the theoretical maximum yield of ATP per glucose molecule oxidized by aerobic respiration.
27Determining the exact yield of ATP for aerobic respiration is difficult for a number of reasons. - bacteria may differ in their carriers in the ETC- the number of ATP generated per reduced NADH or FADH2 is not always a whole number.For every pair of electrons transported to the electron transport chain by a molecule of NADH, between 2 and 3 ATP are generated. For each pair of electrons transferred by FADH2, between 1 and 2 ATP are generated.For simplicity, however, we look at the theoretical maximum yield of ATP per glucose molecule oxidized by aerobic respiration.
29Cellular Respiration Summary 142- Each NADH produces 3 ATP- Each FADH2 produces 2 ATP2 352 6net2 7net34 118NADH910
30Cellular Respiration Summary 2 NADH2 FADH26 NADH- Each NADH produces 3 ATP- Each FADH2 produces 2 ATP2 NADH2 ATP2 ATP net2 ATP net34 ATP possible8 NADH2 FADH26 CO2
31What happens if you don’t get enough oxygen? Fermentation: use of pyruvate to make minimal ATP when there is no O2 = anaerobicThis happens when the Krebs cycle cannot occur due to lack of oxygenBy products of fermentation include lactic acid and alcoholLactic Acid in muscle cells can cause muscle cramps.
32Two Types:Lactic Acid Fermentation: in animals, turns pyruvate into lactic acidAlcoholic Fermentation: in yeast and bacteria, turns pyruvate into ethyl alcohol
34FermentationThis happens when the Krebs cycle cannot occur due to lack of oxygenByproducts of fermentation include lactic acid and alcoholLactic Acid in muscle cells can cause muscle cramps.
35Fermentation Applications of fermentation This happens when the Krebs cycle cannot occur due to lack of oxygenByproducts of fermentation include lactic acid and alcoholLactic Acid in muscle cells can cause muscle cramps.Fermentation is used in making food products and alcohol products. Applications of fermentation
36Aka/ Other Vocab:Oxidative Phosphorylation: (aka ETC of cellular respirations) process in which ATP is formed as a result of the transfer of electrons from NADH or FADH 2 to O 2 by a series of electron carriers. Pre Kreps = Prep Reactions Kreb Cycle= Citric Acid Cycle Why? Substrate Level ATPsynthase= glycolysis and Kreb cycle togetherGTP: Guanosine-5'-triphosphate- GTP is involved in energy transfer within the cell, a GTP molecule is generated by one of the enzymes in the citric acid cycle. This is leads to the generation of one molecule of ATP, since GTP is readily converted to ATP.
38Is the Mitochondrial Genome Still Functional? Evidence of Endosymbiosis:Mitochondrial genomes are very small and show a great deal of variation as a result of divergent evolution. Mitochondrial genes that have been conserved across evolution include rRNA genes, tRNA genes, and a small number of genes that encode proteins involved in electron transport and ATP synthesis.The mitochondrial genome retains similarity to its prokaryotic ancestor, as does some of the machinery mitochondria use to synthesize proteins. In fact, mitochondrial rRNAs more closely resemble bacterial rRNAs than the eukaryotic rRNAs found in cell cytoplasm. In addition, some of the codons that mitochondria use to specify amino acids differ from the standard eukaryotic codons.
39Mitochondrial Disease In school, children with mitochondrial disease often seem to work in “spurts” and then “peter out,” becoming lethargic and finding it difficult to concentrate.It ranges from intermittent difficulty thinking, remembering, moving and acting, to severe handicaps. Some results may be fatigue, muscle weakness and diabetes.What do you think, at the molecular level, is causing these symptoms?
40What are the 3 stages of cellular respiration? 1. 2. 3.
41Food for thought 1. What is the purpose of cellular respiration? 2. Where does cellular respiration occur within the cell?3. What is the waste product of cellular respiration?Would you go to an oxygen bar?
434. Compare Photosynthesis to Respiration a. Where does each occur?b. What are the products of each?c. What compounds are needed to start the processes?d. What is the function of the electron transport chain in each processe. Describe the role of ATPase in both processes.
45Photophosphorylation vs Oxidative Phosphorylation:
46Self Test1. In order to produce energy, cells start with glycolysis. If oxygen is NOT present after glycolysis, what process occurs next? a) Electron Transport Chain b) Krebs Cycle c) Fermentation 2. If oxygen IS present after glycolysis, what process occurs next? a) Electron Transport Chain b) Krebs Cycle c)Fermentation3. A process that does NOT require oxygen is known as what? a) Aerobic b) Anaerobic4. In glycolysis, glucose is broken into 2 molecules of __________________ acid5. Where does the Kreb's cycle occur? _________________6. What gas is a waste product produced in the Krebs cycle? ____
477. What enzyme is used in the electron transport chain to create ATP? a. citric acid b. pyruvate c. ATPase8. Where does glycolyis occur?a. cytoplasm b. mitochondria c. chloroplast9. Which process produces the largest amount of ATP?a. fermentation b. Krebs Cycle c. ETC10. The oxygen required by cellular respiration is reduced and becomes part of which molecule?a. ATP b. CO2 c. H20
48The Mystery of the Seven Deaths Case Study: http://sciencecases.lib.buffalo.edu/cs/files/cellular_respiration.pdfIn this case study, students learn about the function of cellular respiration and the electron transport chain and what happens when that function is impaired. Students play the role of medical examiner as they analyze the autopsy results to determine the cause of the mysterious deaths of these seven victims. Explain the overall purpose of cellular respiration.Describe the intermediate metabolites of cellular respiration.Explain the function and importance of the electron transport chain.Describe the role of oxygen in cellular respiration
49trophic level: each step in a food chain or food web, feeding level Third level ConsumerSecondary ConsumersPrimary ConsumerProducer
5090% is used for metabolic activity and is given off as heat. Tropic levels10% of the energy at one trophic level is available for organisms at the next trophic level.90% is used for metabolic activity and is given off as heat.Tropic levels clip