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Energy!!

Energy!!. The work for a cell includes:. reproduction growth making organelles making proteins repair of damaged cell parts movement active transport so, the cells need fuel to do work Food = Fuel. There are 2 ways that organisms can obtain food:.

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Energy!!

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  1. Energy!!

  2. The work for a cell includes: • reproduction • growth • making organelles • making proteins • repair of damaged cell parts • movement • active transport so, the cells need fuel to do work Food = Fuel

  3. There are 2 ways that organisms can obtain food: Autotrophs- organisms that are capable of making their own food ex. Plants use energy from sunlight to produce carbohydrates (photosynthesis) Heterotrophs- organisms that must get energy from food they ingest. ex. All animals and fungi break chemical bonds in large food molecules which releases energy (cellular respiration)

  4. ENERGY FLOW AND CHEMICAL CYCLING IN THE BIOSPHERE • Fuel molecules in food represent solar energy. • Energy stored in food can be traced back to the sun • Animals depend on plants to convert solar energy to chemical energy. • This chemical energy is in the form of sugars and other organic molecules

  5. So who’s doing this? • Both plants and animals perform cellular respiration. • Cellular respiration is a chemical process that harvests energy from organic molecules. • The waste products of cellular respiration, CO2 and H2O, are used in photosynthesis.

  6. Cellular Respiration • The term cellular respiration refers to the biochemical pathway by which cells release energy from the chemical bonds of food molecules and provide that energy for the essential processes of life. • All living cells must carry out cellular respiration. It can be aerobic respiration in the presence of oxygen or anaerobic respiration (no oxygen).

  7. The energy currency of these cells is ATP, and one way to view the outcome of cellular respiration is as a production process for ATP.

  8. Where is it happening? • Glycolysis occurs in the cytosol and the remaining processes take place in mitochondria.

  9. The Overall Equation of Cellular Respiration 36 C6H12O6 + 6O2→ 6CO2 + 6H2O + 38 ATP

  10. Stage One: Glycolysis Stage Two: Kreb’s Cycle Stage Three: Electron Transport Chain Overview of Cellular Respiration

  11. An analogy can be drawn between the process of cellular respiration in our cells and a car. • The mitochondria are the engines of our cells where sugar is burned for fuel and the exhaust is CO2 and H2O.

  12. Stage 1: Glycolysis • Glycolysis breaks a six-carbon glucose into two pyruvic acid molecules. • This happens in the cytoplasm of the cell. • This is the only one of the 3 steps that occurs in BOTH types of cellular respiration (aerobic and anaerobic). • 2 ATP and 2 NADH are produced. • NADH transports H to the third step of cellular respiration where it will be converted into ATP as well.

  13. 2 Pyruvic acid Glucose

  14. Glycolysis: • http://programs.northlandcollege.edu/biology/Biology1111/animations/glycolysis.html • http://programs.northlandcollege.edu/biology/Biology1111/animations/glycolysis.html

  15. Transition Reaction: • Pyruvic acid is converted into usable form acetyl Co-A. • Begins with the removal of a carbon and two oxygens (which form carbon dioxide).When the carbon dioxide is removed, energy is given off, and NAD+ is converted into the higher energy form NADH. • Coenzyme A attaches to the remaining 2-C (acetyl) unit, forming acetyl Co-A. CoA acetic acid Acetyl-CoA (acetyl-coenzyme A) Pyruvic Acid Coenzyme A CO2

  16. Stage 2: Krebs Cycle • The cycle generates 1 ATP per turn of acetyl co-A by phosphorylation. • Most of the chemical energy is transferred during the redox reactions of NAD+ and FAD. • NADH and FADH2 deliver their cargo of high energy electrons to the electron transport chain. • Carbon dioxide is produced as a by-product during the Krebs cycle. What is FADH2? FAD (Flavin adenine dinucleotide) is a cofactor in the enzymes glucose oxidase. FADH and FADH2 are reduced forms of FAD.

  17. Input Output 2 Acetic acid 1 2 CO2 ADP 3 Krebs Cycle 3 NAD 4 FAD 5 6 Figure 6.11

  18. Stage 3: Electron Transport Chain • During the electron transport chain FADH2 and NADH from the first two steps deliver hydrogen ions which are used to convert ADP into ATP. • A total of 32 or 34 ATP is produced. • Happens on the inner membrane of the mitochondria (the cristae).

  19. Chemiosmosis: • The process by which ATP is produced in the inner membrane of a mitochondrion. • The electron transport system transfers protons from the inner compartment to the outer; as the protons flow back to the inner compartment through ATP synthase, the energy of their movement is used to add phosphate to ADP, forming ATP.

  20. Cytochrone a3 : one missense DNA mutation causes this enzyme to become inactive and the electron transport chain does not complete the process of ATP production effeiciently. The person builds up lactic acid and has severe muscle pain and cramping continuously with any kind of exertion, even walking. Treatment: vitamins C and K.

  21. A Road Map for Cellular Respiration Cytosol Mitochondrion High-energy electrons carried mainly by NADH High-energy electrons carried by NADH Glycolysis Krebs Cycle 2 Pyruvic acid Electron Transport Glucose Figure 6.7

  22. Cellular respiration in “real life” • Bacteria are used to produce yogurt, sour cream, pepperoni, and cheese • Both carbon monoxide and cyanide kill by disrupting cellular respiration

  23. When enough oxygen reaches cells to support energy needs • Anaerobic metabolism in our muscles • When the demand for oxygen outstrips the body’s ability to deliver it, the body tries to continue providing energy • Without oxygen, it can only partially break down glucose and only release part of the energy it contains • Aerobic metabolism in our muscles

  24. Anaerobic cellular respiration • Certain organisms accomplish anaerobic cellular respiration (without oxygen). • There are two types: 1) lactic acid fermentation and 2) alcoholic fermentation. • Anaerobic cellular respiration is much LESS efficient. (2ATP in total instead of 36 or 38 ATP).

  25. 1) Lactic acid fermentation • This type of anaerobic cellular respiration is done by our own cells when not enough oxygen is present, also by certain bacteria to produce sour cream, yogourt and pepperoni. Only glycolysis happens, producing 2 ATP and lactic acid. This is much LESS efficient then aerobic cellular respiration.

  26. Lactic acid fermentation When you exercise: • Muscles need energy in order to perform work • Your cells use oxygen to release energy from the sugar glucose • If you exercise too hard, your muscles shut down from a lack of oxygen.

  27. Anaerobic metabolism • Without enough oxygen, muscle cells break down glucose to produce lactic acid • Lactic acid causes the “burn” associated with heavy exercise • Lactic acid is toxic. So if too much lactic acid builds up, the body lets you know through pain – the “burn”

  28. Physical conditioning allows your body to adapt to increased activity • The body can increase its ability to deliver oxygen to muscles • Long-distance runners wait until the final sprint to exceed their aerobic capacity

  29. 2) Alcoholic fermentation • Yeasts (unicellular fungi) and certain bacteria can undergo this type of anaerobic cellular respiration. They convert glucose into alcohol and carbon dioxide. Only 2 ATP are produced (only glycolysis). • We use yeasts to make beer, champagne, and bread!

  30. References http://videos.howstuffworks.com/discovery/29543-assignment-discovery-cellular-respiration-video.htm • http://www.bpcc.edu/sciencealliedhealth/humanphysiologylinks.html

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