Cellular Respiration ch 8

Cellular Respiration Have you ever wondered why exactly you need to breathe? What happens when you stop breathing?

Cellular 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!

C 6 H 12 O 6 + 6O 2 -->6 CO 2 + 6H 2 O + 36 ATP

How are they connected? glucose + oxygen  carbon + water + energy dioxide C 6 H 12 O 6 6O 2 6CO 2 6H 2 O ATP  +++ Heterotrophs + water + energy  glucose + oxygen carbon dioxide 6CO 2 6H 2 O C 6 H 12 O 6 6O 2 light energy  +++ Autotrophs making energy & organic molecules from light energy making energy & organic molecules from ingesting organic molecules Where ’ s the ATP? oxidation = exergonic reduction = endergonic

O 2 or no O 2 Aerobic Respiration: requires oxygen (air) (breathing) Anaerobic Respiration: does not need oxygen (no air) (breathing)

AEROBIC = 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

There are three stages 1. Glycolysis 2. Kreb's Cycle (Citric Acid Cycle) 3. Electron Transport Chain

net yield of 2 ATP per glucose molecule net yield of 2 NADH per glucose molecule GLYCOLYSIS GLYCOLYSIS = "glyco - lysis " is the splitting of a 6 carbon glucose into two pyruvates, each having 3 carbons can occur without oxygen

Stage 1: Glycolysis: Anaerobic = no O 2 needed Occurs in cytoplasm Occurs in all organisms: prokaryote and eukaryote Net of 2ATP Products: 2 ATP 2 NADH 2 Pyruvic Acids

Stage 1: Glycolysis: Anaerobic = no O 2 needed Occurs in cytoplasm Occurs in all organisms: prokaryote and eukaryote Net of 2ATP Products: 2 ATP 2 NADH 2 Pyruvic Acids

Equation for Cellular Respiration: oxidation & reduction REDOX reactions in respiration – release energy as breakdown organic molecules break C-C bonds strip off electrons from C-H bonds by removing H atoms – C 6 H 12 O 6  CO 2 = the fuel has been oxidized electrons attracted to more electronegative atoms – in biology, the most electronegative atom? – O 2  H 2 O = oxygen has been reduced – couple REDOX reactions & use the released energy to synthesize ATP C 6 H 12 O 6 6O 2 6CO 2 6H 2 O 36ATP  +++ oxidation reduction or 38 *Need mitochondria and enzymes to make this happen!

Mitochondria: power house Label on your paper

QOD continued from cell respiration summary 1.What does cellular respiration produce? 2.Does it need light? 3.What does anaerobic mean? 4.What does aerobic mean? 5.What is the equation for cellular respirations?

2. Citric Acid or Krebs Cycle - occur ONLY if oxygen is present and the cell has mitochondria. - In this stage of cellular respiration, the oxidation of glucose to CO 2 is completed. (this is why we exhale carbon dioxide) It is not necessary to know the individual steps Hans Krebs

Pre Krebs: The pyruvic acid (C 3 ) loses a C to CO 2 and use a H + to form NADH and becomes Acetyl Co-A (C 2 ). Simple put: Pyruvate is converted to Acetly CoA – releases 2 CO 2 – reduces 2 NAD  2 NADH (moves e - ) – produces 2 acetyl CoA Acetyl CoA enters Krebs cycle

Citric acid Krebs Cycle Overview Products (per glucose) 2 ATP 6 CO2 8 NADH 2 FADH 2. These energy carriers now enter the electron transport chain (ETC). Aerobic Occurs in the matrix (inner compartment)

4C6C4C 2C6C5C4C CO 2 citrate acetyl CoA Count the C & electron carriers! 3C pyruvate reduction of electron carriers This happens twice for each glucose molecule x2x2 CO 2 NADH FADH 2 ATP

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…. ETC 3. Electron Transport System:

Does this picture look familiar? You've seen this before in photosynthesis. Animation of the ETCAnimation of the ETC McGraw Hill AnimationMcGraw Hill Animation Products: 34 ATP

McGraw Hill Animation ew0/chapter9/animations.html#

McGraw Hill Animation NAD dehydrogenase Coenzyme Q Coenzyme c Bc complex Cytochrome c oxidase complex ATP synthase FADH NADH ADP

McGraw Hill Animation NAD dehydrogenase Coenzyme Q Coenzyme c Bc complex Cytochrome c oxidase complex ATP synthase FADH NADH H2OH2O ADP

McGraw Hill Animation NAD dehydrogenase Coenzyme Q Coenzyme c Bc complex Cytochrome c oxidase complex ATP synthase FADH NADH H2OH2O ADP

Breakdown of One Glucose Molecule Calculations from each: NADH= 2 or 3 ATP can be made FADH 2 = 2 ATP can be made 1. Glycolysis – Produces: 2 ATP2 NADH 2. Krebs Cycle (including “ pre-Kreb ’ s ” ) - Produces: 2 ATP 8 NADH 2FADH 2 Total:4ATP10 NADH 2 FADH 2 3. ETC - Produces:x 3 x 2 30 ATP 4 ATP = 34 ATP Total: 4ATP + 34 ATP + a grand total of 38 ATP ! Theoretical Yield For simplicity, however, we look at the theoretical maximum yield of ATP per glucose molecule oxidized by aerobic respiration.

Determining 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.

-net yield of 32 or 34 ATP per glucose molecule - 6 H 2 O are formed when the electrons unite with O 2 * 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.

Cell Respiration Lab

1 2 6net NADH Cellular Respiration Summary net Each NADH produces 3 ATP - Each FADH 2 produces 2 ATP

2 NADH 2 ATP net 2 ATP 2 NADH 6 NADH 8 NADH Cellular Respiration Summary 2 FADH 2 6 CO 2 2 ATP net 34 ATP possible - Each NADH produces 3 ATP - Each FADH 2 produces 2 ATP

What happens if you don’t get enough oxygen? Fermentation: use of pyruvate to make minimal ATP when there is no O 2 = anaerobic By products of fermentation include lactic acid and alcohol Lactic Acid in muscle cells can cause muscle cramps. This happens when the Krebs cycle cannot occur due to lack of oxygen

Fermentation Byproducts of fermentation include lactic acid and alcohol Lactic Acid in muscle cells can cause muscle cramps. This happens when the Krebs cycle cannot occur due to lack of oxygen

Two Types: 1.Lactic Acid Fermentation: in animals, turns pyruvate into lactic acid 2.Alcoholic Fermentation: in yeast and bacteria, turns pyruvate into ethyl alcohol

Lactic Acid Fermentation Alcoholic Fermentation

Fermentation is used in making food products and alcohol products. Applications of fermentation Fermentation Byproducts of fermentation include lactic acid and alcohol Lactic Acid in muscle cells can cause muscle cramps. This happens when the Krebs cycle cannot occur due to lack of oxygen

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 together Aka/ Other Vocab: GTP: 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.

Why is it called the citric acid cycle?

Is 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.

Mitochondrial 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?

What are the 3 stages of cellular respiration?

Food 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?

4. 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 process e. Describe the role of ATPase in both processes.

Photosynthesis – Respiration Cycle

Photophosphorylation vs Oxidative Phosphorylation:

Self Test 1. 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)Fermentation 3. A process that does NOT require oxygen is known as what? a) Aerobic b) Anaerobic 4. In glycolysis, glucose is broken into 2 molecules of __________________ acid 5. Where does the Kreb's cycle occur? _________________ 6. What gas is a waste product produced in the Krebs cycle? ____

7. What enzyme is used in the electron transport chain to create ATP? a. citric acid b. pyruvate c. ATPase 8. Where does glycolyis occur? a. cytoplasm b. mitochondria c. chloroplast 9. Which process produces the largest amount of ATP? a. fermentation b. Krebs Cycle c. ETC 10. The oxygen required by cellular respiration is reduced and becomes part of which molecule? a. ATP b. CO 2 c. H 2 0

The Mystery of the Seven Deaths Case Study: In 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

trophic level: each step in a food chain or food web, feeding level Producer Third level Consumer Secondary Consumers Primary Consumer

Tropic levels 10% 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 60369