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CELLULAR RESPIRATION

CELLULAR RESPIRATION. Cellular respiration is defined as the controlled release of energy from organic compounds to form ATP ( Adenosin Tri-Phosphate ) When ATP is split into ADP (adenosine diphosphate ) and phosphate, energy is released. Cell respiration. ADP + phosphate. ATP.

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CELLULAR RESPIRATION

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  1. CELLULAR RESPIRATION

  2. Cellular respiration is defined as the controlled release of energy from organic compounds to form ATP (Adenosin Tri-Phosphate) • When ATP is split into ADP (adenosine diphosphate) and phosphate, energy is released Cell respiration ADP + phosphate ATP Active cell process

  3. Glycolisis • The main organic compounds from which energy is released are carbohydrates (glucose) and lipids. These are the substrates. • The chain of reactions that take place in the cytoplasm of the cell to convert glucose to pyruvate is called glycolysis. • As a result, a small amount of ATP is produced. glucose  pyruvate ADP ATP Occurs in almost all organisms, in aerobic or anaerobic cell respiration

  4. Anaerobic cell respiration • Under anaerobic conditions, pyruvate can go through one of the following paths: pyruvate  lactate Occurs in humans and some bacteria in anaerobic cell respiration pyruvate  ethanol +CO2 Occurs in yeast in anaerobic cell respiration • No more ATP is produced • These substances are toxic in excess

  5. Aerobic cell respiration • In the presence of oxygen, the pyruvate produced by glycolysis can be oxidized to release more energy. • In eukaryotic cells this occurs in the mitochondrion. • During this process more ATP is produced. • Carbon dioxide and water are also produced. MITOCHONDRION Glucose glycolysispyruvate Oxygen H2O CO2

  6. Checking our knowledge • Cell respiration is: • Taking air into our lungs • Removing carbon dioxide from the lungs • Use of ATP in cells • Controlled release of energy in cells • What are the products of glycolysis? • Glucose • Glucose and ATP • ATP and pyruvate • Glucose, ATP and pyruvate • Which substances are produced by yeast in anaerobic cell respiration? • Carbon dioxide and lactate • Carbon dioxide and ethanol • Lactate and ethanol • Carbon dioxide, lactate and ethanol • Where is pyruvate used and produced in a cell respiring aerobically? • Cytoplasm / cytoplasm • Cytoplams / mitochondrion • Mitochondrion /cytoplasm • Mitochondrion / mitochondrion

  7. HL ONLY

  8. Questions for the group activity • GROUP 1 (2) Glycolysis: • Describe the complete process of glycolysis • Where glycolysis take place? • What is the net production of ATP of this process? Why? • Explain why NAD is needed for glycolysis • GROUP 2: (3) Krebs cycle • Describe the Krebs cycle • Where the Krebs cycle takes place? • What is the name of the reaction in which CO2 is removed? • What is the net production of ATP of this process? Why? • GROUP 3 (1) Oxidation and reduction: • What is oxidation and reduction: give an example to show the processes • What are electron carriers in cells: explain how they work (4) Mitochondrion structure and function • Draw a mitochondria and label its parts • What can be found in the matrix of a mitochondrion? • How can you explain the presence of DNA and ribosomes in the Mitochondria? • GROUP 4 (5) Oxidative phosphorilation • Describe the process of oxidative phosphorilation (electron transport system) • Why is oxygen important in this process? • How is the structure of a mitochondria related to its function?

  9. Oxidation and Reduction • Oxidation is the loss of electrons from a substance • Reduction is the gain of electrons Example: NaOH + HCl NaCl + H2O sodium + hydrochloric sodium water hydroxide acid chloride In this equation: Sodium is oxidized, it gives away (losses) electrons Chlorine is reduced, it receives (gains) electrons

  10. Electron carriers in cells • Substances that accept and give up electrons as required • NAD (nicotinamide adenine dinucleotide) • NADP (nicotinamide adenine dinucleotide phosphate) • FAD (flavin adenine dinucleotide) • How it works: NAD + 2 electrons NAD-2 Processes: NAD+ + 2 H NADH + H+ NAD+ + 2 H+ + 2 e- NADH + H+ reduced The reduced substance provides H atoms

  11. Oxidation and reduction can also occur through the loss or gain of atoms of oxygen. C7 H15 ----- CH3 + ½ O2 C7H15 --- CH2 OH n - octane n- octanol NO2- + ½ O2  NO3- • Adding oxygen atoms is oxidation • Losing oxygen atoms is reduction.

  12. Glycolysis Glucose Fructose ATP ADP 4 ATPs used 2 ATPs produced 2 NADH + H+ produced Fructose Phosphate P ATP ADP Fructose Bi Phosphate P P P P Glyceraldehyde 3-P Glyceraldehyde 3-P NAD+ NADH+ H+ NAD+ NADH+ H+ ATP ADP ATP ADP 1-3diphosphoGlycerate P P P P 1-3 diphosphoGlycerate 2 ADP 2 ATP 2 ADP 2 ATP Pyruvate Pyruvate

  13. The Krebs Cycle Pyruvate NAD+ NADH + H+ CO2 3 (2) CO2 1 (2) ATP 3 (2) H2O 4 (2) NADH + H+ 1( 2) FADH2

  14. Mitochondrion structure and function • Structures: • Outer smooth membrane • Inner membrane with cristae • Matrix • Enzymes • Ribosomes • Loops of DNA

  15. Oxidative phosphorilation • Converts the energy in NADH + H+and FADH2 to ATP • It occurs in the mitochondrion membrane Process: Electrons are transferred from NADH, through a series of electron carriers, to O2. The electron carriers are proteins embedded in the inner mitochondrial membrane.

  16. Oxidative phosphorilation • Transfer of electrons by these carriers generates a proton (H+) gradient across the inner mitochondrial membrane.

  17. Oxidative phosphorilation • When H+ spontaneously diffuses back across the inner mitochondrial membrane, ATP is synthesized. • The large positive free energy of ATP synthesis is overcome by the even larger negative free energy associated with proton flow down the concentration gradient.

  18. Totals in respiration • Glycolysis: 2 ATP • Krebs cycle: 2 ATP • Oxidative phosphorilation: 32 ATP

  19. Checking our knowledge: • What separates the matrix of the mitochondrion from the cytoplasm around the mitochondrion? • One wall • One membrane • Two membranes • One wall and one membrane • The mitochondrion matrix contains 70S ribosomes whereas the cytoplasm of eukaryotic cells contains 80S ribosomes. Which of these hypotheses is consistent with this observation? • Protein is synthesized in the mitochondrion • Ribosomes in mitochondria have evolved from ribosomes in bacteria • Ribosomes are produced by aerobic cell respiration • State the name of a compound in cell respiration that can: • Accept hydrogen atoms • Accept phosphate • Explain the reasons for a much lower ATP yield per glucose from anaerobic cell respiration than from aerobic cell respiration

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