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Cellular Respiration (CRs)

Cellular respiration is essential for all living organisms as it is the process by which cells release energy needed for various activities. There are two types of cellular respiration - aerobic and anaerobic. This process is vital for everyday life and provides the energy required for cell functions such as chromosome movement, active transport, and muscle contraction. ATP and glucose are the cellular currency for energy transfer, with ATP being the loonies and glucose being the 100 dollar bill. The overall efficiency of energy transfer in cellular respiration is low, but the loss of energy as thermal energy is used by some organisms to maintain body temperature. Aerobic respiration takes place in the presence of oxygen and produces CO2, H2O, and 36 ATP, while anaerobic respiration occurs in the absence of oxygen and produces ethanol or lactic acid and 2 ATP. This process occurs in the cytoplasm and mitochondria of cells.

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Cellular Respiration (CRs)

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  1. Cellular Respiration (CRs)

  2. Why is CRs Important?

  3. Cellular Respiration All living organisms undergo CRs CRs is the process cells use to release ENERGY needed for all kinds of work There are TWO types of CRs AEROBIC CRs and ANAEROBIC CRs Each of these types produces different end PRODUCTS IS ESSENTIAL TO EVERYDAY LIFE – ALL ACTIVITIES THAT YOUR BODY PERFORMS REQUIRES some form of Cellular Respiration

  4. What Do Cells need ENERGY for? • Cells require ENERGY in the form of ATP • Energy demands of cells are very diverse • Chromosome movement (cell division) • Active Transport of Materials • Large scale movement – muscle contraction A SINGLE human cell contains approx ONE BILLION ATP MOLECULES!!!!

  5. Cells, ATP and GLUCOSE • GLUCOSE is a high energy molecule that is small enough to diffuse into our blood (“blood sugar”) • BENEFICIAL/USEFUL form of energy storage in cells • Breaking bonds consumes energy and RELEASES energy • CRs = overall (NET) energy RELEASE

  6. Efficiency of CRs • Overall efficiency of energy transfer is quite LOW (~36%) • BUT the loss of energy in the transfer as THERMAL energy is used by some organisms to maintain body temperature!! • Meaning that about 36% of the energy in a SINGLE glucose molecule is converted into ATP – energy available for the cell

  7. ATP and GLUCOSE = CELLULAR CURRENCY ANALOGY 1 dollar = loonie 100 dollars = 100 dollar BILL *** Compare how MANY of each *** $100 = 100 loonies/1 bill Which would be more useful in a vending machine???? ATP is like the loonies GLUCOSE is like the 100 dollar bill Cell is like the vending machine RELATION TO EFFICIENCY: like exchanging your 100 dollar bill and getting 36 loonies!!!!

  8. Cellular Respiration • Takes place in the cytoplasm and mitochondria

  9. Plant/Animal Cell Review!!!!

  10. Membrane StructurePhospholipid Bilayer

  11. Mitochondria

  12. Room Set Up Walls of the classroom = cell membrane Green Tape = mitochondrial membranes Black/Yellow tape at front of room = channel proteins Back of room (by back door) = cytoplasm Rest of room (inside green tape) = mitochondria

  13. What activity are these people doing?

  14. Types of Cellular Respiration • Aerobic CRs – takes place in the presence of OXYGEN • PRODUCTS = CO2 , H2O, 36 ATP • 4 Stages: • Stage 1: Gylcolysis • Stage 2: Pyruvate Oxidation • Stage 3: Krebs Cycle • Stage 4: ETC and Chemiosmosis

  15. Types of Cellular Respiration • Anaerobic CRs – takes place in the absence of OXYGEN • Two Types • PRODUCTS = ethanol (C2H5OH), CO2, 2 ATP • PRODUCTS = lactic acid (C3H6O3), 2 ATP • 2 Stages: • Stage 1: glycolysis • Stage 2: fermentation http://www.science.nelson.com/ABbio20-30/teacher/protect/otr/Bio2030OTR/attachments/i_AnimationSimulation/energy_releasing.html

  16. Background Info • ATP = ADP + phosphate • Reduction and Oxidation (REDOX) reactions involve the transfer of electrons “LEO GER” • Lose Electron Oxidation • Gain Electron Reduction *** NADH = NAD+ + electrons *** FADH2= FAD + electrons BOTH MOLECULES ARE ELECTRON CARRIERS IN THEIR REDUCED FORM

  17. Glycolysis • The first stage in any CRs reaction • Means “sugar splitting” • Takes the 6 carbon glucose molecule and “splits” it into two 3 carbon pyruvate molecules • Takes place in the CYTOPLASM http://www.nelson.com/ABbio20-30/teacher/protect/otr/Bio2030OTR/attachments/i_AnimationSimulation/glycolysis.html

  18. Glycolysis • Begins with a single glucose molecule • This chain then SPLITS into PGAL (phosphogluteraldehyde) • 2 NAD+ are reduced from the PGAL by taking e- and H+ from each to form 2 NADH and releasing 2 additional H+ into the cytoplasm • Total of 2 ATP are produced by removing phosphates from the carbon molecule

  19. The two 3 carbon chains have formed PYRUVATE molecules – the LAST step in glycolysis • PYRUVATE = C3H4O3

  20. In aerobic respiration the 2 NADH produced from glycolysis are converted into FADH2 http://www.youtube.com/watch?v=nKgUBsC4Oyo http://www.youtube.com/watch?v=AFLu6lhF1YI&feature=related

  21. Try it out!!I need 14 volunteers 6 carbons “atoms” 2 ATP “molecules” 2 ADP “molecules” 2 NAD+ “molecules” 2 FAD “molecules”

  22. Aerobic Respiration • Involves the use of OXYGEN • The following steps are involved in aerobic respiration • Pyruvate oxidation • Krebs Cycle • ETC and Chemiosmosis

  23. Pyruvate OxidationPreparation for Krebs Cycle Three changes to pyruvate occur • A CO2 portion is removed • NAD+ is reduced to NADH • Coenzyme A attaches to the 2-carbon molecule forming acetyl-CoA http://www.nelson.com/ABbio20-30/teacher/protect/otr/Bio2030OTR/attachments/i_AnimationSimulation/prep_and_krebs.html

  24. Coenzyme A acts like an “escort”, leading the acetyl group to the Krebs cycle • Once the acetyl group has entered the Krebs cycle – it is released and is free to “pick up” another acetyl group

  25. The Krebs Cycle • Starts when acetyl-CoA binds with the 4 carbon starting molecule (oxaloacetate) • 2 CO2 are removed (6C → 5C → 4C)

  26. The Krebs Cycle • 3 NAD+ molecules are reduced to 3 NADH • 1 FAD+ is reduced to 1 FADH2 • 1 ADP is phosphorylated to 1 ATP http://www.nelson.com/ABbio20-30/teacher/protect/otr/Bio2030OTR/attachments/i_AnimationSimulation/prep_and_krebs.html

  27. The Krebs Cycle • TOTAL OUTPUT OF KREBS CYCLE FROM ONE GLUCOSE ** Remember the cycle occurs TWICE for one glucose ** (2 cycles) • 6 NADH • 2 FADH2 • 4 CO2 • 2 ATP

  28. LETS PLAY!!!

  29. Electron Transport Chainand Chemiosmosis

  30. Electron Transport Chainand Chemiosmosis • High energy electron carriers NADH and FADH2 donate their electrons to the ETC • As electrons move through the ETC they release energy causing H+ to move out of the matrix • Oxygen is the final electron acceptor in the chain – without oxygen the entire ETC reaction cannot occur!! • This energy causes H+ ions to move from the intermembrane space into the mitochondrial matrix through ATP synthase complex to attempt to restore the H+ balance • This process releases energy which is used to phosphorylate ADP into ATP!!! • CHEMIOSMOSIS

  31. Electron Transport Chain and Chemiosmosis • REMEMBER Every NADH donating electrons creates enough energy release to form 3 ATP Every FADH2 donating electrons creates enough energy release to form 2 ATP

  32. Electron Transport Chainand Chemiosmosis

  33. Total ATP created from ONE GLUCOSE in aerobic respiration http://www.nelson.com/ABbio20-30/teacher/protect/otr/Bio2030OTR/attachments/i_AnimationSimulation/energy_harvest.html

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