Cellular Respiration

Cellular RespirationHave you ever wondered whyexactly you need to breathe? Whathappens when you stop breathing?

Cellular respiration isthe set of themetabolic reactionsand processes thattake place in the cellsof all organisms toconvert biochemicalenergy from nutrientsinto adenosinetriphosphate (ATP –cell energy), and thenrelease wasteproducts.

Respiration FormulaC6H12O6 6O2 -- 6 CO2 6H2O 36 ATPLook familiar?

The best respiration occurs in thepresence of oxygen - called AEROBICWithout oxygen,fermentation, oranaerobic respiration,is used, but it’s not asgood (We’ll comeback to this )

There are three stages in Aerobic Respiration1. Glycolysis2. Kreb's Cycle (aka Citric AcidCycle)3. Electron Transport Chain andOxidative Phosphorylation

GLYCOLYSIScan occur withoutoxygenGLYCOLYSIS "glyco - lysis " is the splitting of a 6carbon glucose into two 3-Carbon pyruvates- net yield of 2 ATP and 2 NADH perglucose molecule (4 total produced ATP –2 used ATP 2 net produced ATP)

2. Citric Acid or Krebs CycleIt is notnecessary toknow theindividual stepsa) occurs in the mitochondriab) an aerobic process; will proceed only in the presence of O2

- net yield of 2 ATP, 6NADH and 2 FADH2,which are all sent to ETCc) in this stage of cellularrespiration, the oxidationof glucose to CO2 iscompleted.(this is why and when weexhale carbon dioxide)

3. ETC and Ox Phos:a) consists of a series ofenzymes on the innermitochondrial membraneb) electrons are released fromNADH and FADH2 and passedalong a series of enzymes,giving up energy which is usedto fuel chemiosmosisc) Makes ATP with ATPSynthetase (just like the ETC inPhotosynthesis, just differentnames)

c) Total net yield of 32-34 ATP per glucosed) 6 H2O are formed when the electrons unite with O2* at theend of electron transport chain.* Note: This is the function of oxygen in living organisms!Without oxygen to serve as the final electron acceptor, theprocess shuts down.

Does this picture look familiar?You've seen this before inphotosynthesis.Animation of the ETCMcGraw Hill Animation

What about no oxygen situations?Anaerobic Respiration, AKA - FermentationThis happens when the Krebscycle cannot occur due to lackof oxygen; purpose is toregenerate NAD soglycolysis can continueTwo types of fermentation –lactic acid (animals) andalcoholic (yeast/bacteria)Byproducts include lacticacid and alcohol-Note: Lactic Acid in musclecells causes musclecramps.

Fermentation is used inmaking food products andalcohol products.

What are the 3 stagesof cellular respiration?1.2.3.

Food for thought1. 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 toan oxygen bar?

4. Compare Photosynthesis to Respirationa. 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 eachprocesse. Describe the role of ATPase in both processes.

Self Test1. In order to produce energy, cells start with glycolysis. If oxygen isNOT present after glycolysis, what process occurs next?a) Electron Transport Chain b) Krebs Cycle c) Fermentation2. 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) Aerobicb) Anaerobic4. In glycolysis, glucose is broken into 2 molecules ofacid5. 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 tocreate ATP?a. citric acidb. pyruvatec. ATPase8. Where does glycolyis occur?a. cytoplasmb. mitochondriac. chloroplast9. Which process produces the largest amount of ATP?a. fermentationb. Krebs Cyclec. ETC10. The oxygen required by cellular respiration is reduced andbecomes part of which molecule?a. ATPb. CO2c. H20

The Mystery of the Seven DeathsCaseStudy: lar respiration.pdfIn this case study, students learn about the function of cellular respiration andthe electron transport chain and what happens when that function is impaired.Students play the role of medical examiner as they analyze the autopsy resultsto 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