Cellular respiration part 1


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Cellular respiration part 1

  1. 1. Energy and CellularRespiration Chapter 7
  2. 2. Cellular Respiration vs.Photosynthesis• Formulas
  3. 3. Cellular Respiration vs. Photosynthesis• Organelles • Mitochondria • Eukaryotic cells • Structure is key − Two membranes − Space between membranes − Matrix makes up inner membrane – Lots of enzymes found here for chemical reactions − Complex folding=many sites for reactions to take place – Maximizes ATP production • Chloroplast • More about this one later…
  4. 4. Energy• Heat (thermal)• Light (solar)• Chemical • Ex.Glucose• What carries energy? • Electrons (little energy packets) • Negatively charged particle • Involved in making bonds between atoms • Electromagnetic spectrum
  5. 5. Why do cells needenergy?• To Do Work!• What kind of work? • Transport • Get things across the membranes • Mechanical • Moving things around the cell/moving the cell itself • Chemical • Building up/breaking down molecules
  6. 6. How is EnergyTransferred?• Think food chain!• First Law of Thermodynamics aka the Law of Conservation of Energy • E cannot be created or destroyed, only transferred (converted)
  7. 7. Kinetic vs. Potential • Stored energy due to an objects position or• Energy of arrangement • Glucose is has LOTS of motion potential energy…look at all of its bonds• Anything moving (electrons) or in motion• Ex. • Climbing stairs • Leg muscles working • As you climb up, you are getting higher, more gravitational pull, increase potential E
  8. 8. Two Types of KineticEnergy• Directed kinetic • Random kinetic energy energy of molecular• Ex. Your body as motion it moves down • Thermal energy slide • Ex. When your body collides with water. Air and water molecules are forced to move and collide at random, transferring energy
  9. 9. • Thermal Energy • Created from Random molecular motion • “Heat” is thermal energy that is transferred from warmer object to cooler object
  10. 10. How do we getEnergy?....Eat food! • Food is composed of organic compounds • Carbohydrates • Fats • Proteins • All rich in E• These organic compounds contain a form of potential energy we call• CHEMICAL ENERGY
  11. 11. Organic compounds• Potential to do work is in the arrangement of • Structures of… atoms in the molecules • Proteins• Amount of potential • Carbohydrates energy depends on the • Fats structure of the molecules• When you break a bond, you release E• Energy now available for muscles to do work
  12. 12. Cells and Cars useCombustion• Cells • Cars • Glucose • Hydrocarbons (in • Oxygen gasoline) • Energy to do • Oxygen work • Energy to do • Transport, mechanical work mechanical, • Releases carbon chemical dioxide and • Releases carbon water dioxide and water
  13. 13. calorie• Amount of energy required to raise the temperature of 1 g of water 1*C• Very tiny• Not practical to measure energy in food• Express in kilocalories (kcal), or Calories, what is on the nutrition label • KHDmdcm
  14. 14. Burning food…• Changes chemical energy to thermal energy (releases heat)• Measure increase of water temperature and definition of calorie to find out how much chemical energy is in food
  15. 15. Find the amount of calories in each food andwhich provides the most energy1 2 3
  16. 16. Energy From Electrons• Atom nucleus • Positive • Attracts/pulls electrons • Potential energy released when nucleus pulls electrons to it (makes bond)• Think of the atomic structure of the following atoms• Oxygen (make up the oxygen molecule in cell resp)• Hydrogen and Carbon (bonded to each other in glucose)• Which has a stronger attraction for electrons?• What happens in cell respiration? • Oxygen molecule reacts with glucose • Carbon and hydrogen leave each other and become bonded to oxygens, creating the carbon dioxide and water produced in cellular respiration• The electrons in hydrogen and carbon are pulled toward the nucleus of the oxygen atoms, thus releasing potential energy• Occurs when you burn sugar, lots of energy released almost instantaneously• In cellular respiration, occurs in controlled steps to prevent a massive release of energy
  17. 17. Electron TransportChain (etc)• Cell respiration releases E in small amounts in the form of ATP molecules• Several steps• Oxygen is only involved in the end• Electrons=energy• Electrons are carried by electron carrier molecules • Electron carrier is a molecule that can accept a pair of high-E electrons and transfer them along with most of their energy to another molecule• Oxygen is the final electron acceptor that joins with hydrogen ions to make water• This transfer of electrons throughout cellular respiration is called the electron transport chain (ETC)• For every transfer of electrons between molecules in the chain, a little E is released
  18. 18. Cellular Respiration• A cellular process (part of metabolism)• Metabolism • Set of chem. rxns through which an organism builds up or breaks down materials as it carries out life’s processes • Catabolic Rxn  breaking molecules down • Anabolic Rxn  building molecule/putting things together• C6H12O6 (aq) + 6O2 (g) → 6CO2 (g) + 6H2O (l)• Glucose reacts with oxygen to produce carbon dioxide and water• REQUIRES OXYGEN • Aerobic
  19. 19. Cellular Respiration: 3parts1. Glycolysis  cytoplasm2. Kreb’s Cycle  Mitochondrian matrix3. Electron Transport Chain  Within the inner mitochondrial membrane
  20. 20. Mitochondrion Electrons carried in NADH Electrons Pyruvic carried in acid NADH and Glucose FADH2 Electron Krebs Transport Glycolysis Cycle Chain MitochondrionCytoplasm
  21. 21. Cellular Respiration CarbonGlucose Dioxide(C6H1206) Electron Krebs (CO2) + Glycolysis Transport Cycle + Oxygen Chain Water (02) (H2O)
  22. 22. Glycolysis summaryENERGY INVESTMENT endergonic invest some ATP -2 ATP G3PENERGY PAYOFF C-C-C-P exergonic harvest a little 4 ATP ATP & a little NADH like $$ in the bankNET YIELD net yield 2 ATP 2 NADH
  23. 23. Glycolysis• Greek word “glukus” sweet• Latin word “lysis” loosening or decomposing• Def: the process in which one molecule of glucose is broken in half, producing two molecules of pyruvic acid (a three-carbon compound)• Takes place outside mitochondria, in cytoplasm of cell• Energy releasing process• Does NOT require oxygen• Requires an investment of 2 ATP molecules at beginning to get it going • These 2 atp’s are like an investment that pays back with interest • In order to earn money from a bank, you have to put $$ in• 4 molecules of ATP produced at the end of Glycolysis• What is the “net” gain? • 2 ATPs
  24. 24. NADH production• 4 high-E e- are removed and passed to two electron carriers called NAD+ (nicotinamide adenine dinucleotide) (each NAD+ carries 2 e-)• Each NAD+ molecule accepts a pair of high-E e-• Once e- are accepted, NAD+ becomes NADH, which will transfer e- to other molecules• NAD+ helps pass energy from glucose to other pathways in the cell
  25. 25. Glycolysis• Glucose, a six-carbon sugar, receives 2 phosphates from the first 2 ATPs invested in Glycolysis• Glucose now becomes fructose 1,6-biphosphate (highly energized)• Fructose 1,6-biphosphate splits to become two molecules of CCC-P (glyceraldehyde 3-P)• Each of these molecules transfers electrons and hydrogen ions to NAD+ molecules that come in• Accepting two e- and hydrogen ion changes NAD+ to NADH, which carry electrons to the next part of Glycolysis• An inorganic phosphate is added to the CCC-P molecule changing it to P-CCC-P (1,3-biphosphoglycerate)• 2 ADP molecules will come in and snatch off the phosphates from P-CCC-P and the molecule has now become PYRUVATE or PYRUVIC ACID• Pyruvate is then sent on to the next phase, the Kreb’s Cycle
  26. 26. Reactants and Products ofGlycolysis• In • 1 glucose • 2 ATP • 2 NAD+• Out • 2 NADH (to ETC) • 4 ATP • 2 Pyruvates (to Kreb’s cycle) • (Net ATPs 2)
  27. 27. Glucose 2 Pyruvic acid To the electron transport chain