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Energy & The Cell Glycolysis, Cellular Respiration & Fermentation
Energy <ul><li>All life requires energy </li></ul><ul><li>Therefore cells require energy </li></ul><ul><ul><li>for growth,...
Recycling Energy
ATP <ul><li>Cells store energy in the chemical bonds of sugar, but cannot use it directly </li></ul><ul><li>To use this en...
Structure of ATP <ul><li>The base, adenine </li></ul><ul><li>The sugar, ribose </li></ul><ul><li>Ribose is bound to a chai...
Phosphorylation forms ATP
Releasing Energy from ATP <ul><li>If the cell needs energy it breaks the last phosphate bond, releasing energy </li></ul><...
 
Fermentation <ul><li>So, where does ATP come from? </li></ul><ul><li>Fermentation  =  breakdown of glucose, yielding ATP, ...
Types of Fermentation <ul><li>2 kinds: </li></ul><ul><li>Alcoholic fermentation:   </li></ul><ul><ul><li>occurs in micro-o...
Fermentation in the Cytosol <ul><li>Fermentation  occurs in the cytosol </li></ul><ul><li>It produces  lactic acid  or  al...
Glycolysis <ul><li>Occurs in the cytoplasm of the cell </li></ul><ul><li>One molecule of glucose is split into two molecul...
Energy of Glycolysis
The Role of NAD in Glycolysis <ul><li>During the conversion of glucose to  pyruvic acid , hydrogen is released </li></ul><...
Summary of Glycolysis - Investment
Summary of Glycolysis - Payoff
Energy of Fermentation <ul><li>As a result of fermentation, each molecule of glucose yields 2 molecules of ATP   </li></ul...
Alcoholic Fermentation <ul><li>Pyruvic acid from glycolysis combines with H from NADH 2  to produce  ethyl alcohol </li></...
Alcoholic Fermentation Pathway
Lactic Acid Fermentation <ul><li>Pyruvic acid  combines with H from NADH 2  to produce  lactic acid: </li></ul><ul><li>2CH...
Lactic Acid Fermentation Pathway
Uses of Lactic Acid Fermentation <ul><li>During strenuous exercise  glycolysis  occurs at a high rate </li></ul><ul><li>Py...
Cellular Respiration <ul><li>Most cells produce ATP by breaking the energy containing bonds of glucose in the presence of ...
The Process of Cellular Respiration <ul><li>C 6 H 12 O 6   +  6 O 2      6 CO 2   +  6 H 2 O  +  energy </li></ul><ul><li...
Cellular Respiration Overview
Anaerobic Stage <ul><li>The anaerobic stage of cellular respiration is  glycolysis , the same pathway used in fermentation...
Energy of Glycolysis
Aerobic Stage <ul><li>After  glycolysis , the chemical bonds of  pyruvic acid  are broken down in a series of chemical rea...
Pyruvate Forms Acetyl CoA
The Citric Acid Cycle <ul><li>Steps to break down  pyruvic acid : </li></ul><ul><li>In the presence of O 2 ,  pyruvic acid...
Energy from the Citric Acid Cycle <ul><li>For each molecule of  acetyl CoA  that enters the cycle, 8 atoms of H are releas...
 
The Electron Transport Chain <ul><li>NADH 2  releases the hydrogen atoms trapped during  glycolysis  & the  citric acid cy...
Oxygen & The Electron Transport Chain <ul><li>The last part of the chain is the electron acceptor, oxygen </li></ul><ul><l...
Chemiosmosis <ul><li>The process of formation of ATP during the ETS of aerobic respiration as the result of a pH gradient ...
Picturing Chemiosmosis
Cellular Respiration Summary <ul><li>Thus for every molecule of glucose that is broken down by glycolysis and respiration,...
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Cellular Energy pt.2

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Cellular Energy pt.2

  1. 1. Energy & The Cell Glycolysis, Cellular Respiration & Fermentation
  2. 2. Energy <ul><li>All life requires energy </li></ul><ul><li>Therefore cells require energy </li></ul><ul><ul><li>for growth, active transport, synthesis of carbohydrates, lipids, & proteins </li></ul></ul><ul><li>The source of energy for cells is the energy stored in chemical bonds of organic molecules </li></ul><ul><ul><li>these molecules = food molecules, especially carbohydrates (also lipids) </li></ul></ul><ul><ul><li>most common is glucose </li></ul></ul>
  3. 3. Recycling Energy
  4. 4. ATP <ul><li>Cells store energy in the chemical bonds of sugar, but cannot use it directly </li></ul><ul><li>To use this energy, the cell must transfer the energy in sugar molecules to ATP </li></ul><ul><li>ATP = adenosine triphosphate </li></ul>
  5. 5. Structure of ATP <ul><li>The base, adenine </li></ul><ul><li>The sugar, ribose </li></ul><ul><li>Ribose is bound to a chain of 3 phosphate molecules connected by high energy bonds </li></ul>
  6. 6. Phosphorylation forms ATP
  7. 7. Releasing Energy from ATP <ul><li>If the cell needs energy it breaks the last phosphate bond, releasing energy </li></ul><ul><li>ATP  ADP + P + energy </li></ul><ul><li>Almost all energy requiring processes in cells use ATP as the energy source </li></ul>
  8. 9. Fermentation <ul><li>So, where does ATP come from? </li></ul><ul><li>Fermentation = breakdown of glucose, yielding ATP, without O 2 </li></ul><ul><li>The first living organisms were single cells that existed without O 2 </li></ul><ul><ul><li>Anaerobic </li></ul></ul><ul><ul><li>Lack the enzymes needed to break down energy molecules with O 2 </li></ul></ul><ul><li>Many types of bacteria and other single celled organisms still use anaerobic processes to convert energy </li></ul>
  9. 10. Types of Fermentation <ul><li>2 kinds: </li></ul><ul><li>Alcoholic fermentation: </li></ul><ul><ul><li>occurs in micro-organisms such as yeast </li></ul></ul><ul><li>Lactic acid fermentation: </li></ul><ul><ul><li>occurs in bacteria and animal cells </li></ul></ul>
  10. 11. Fermentation in the Cytosol <ul><li>Fermentation occurs in the cytosol </li></ul><ul><li>It produces lactic acid or alcohol </li></ul><ul><li>Fermentation begins with the process of glycolysis, which is also part of aerobic respiration. </li></ul>
  11. 12. Glycolysis <ul><li>Occurs in the cytoplasm of the cell </li></ul><ul><li>One molecule of glucose is split into two molecules of a three carbon compound called pyruvic acid </li></ul><ul><li>2 molecules of ATP provide the energy to split the glucose molecule </li></ul><ul><li>When glucose splits, it releases enough energy to form 4 molecules of ATP from ADP + P </li></ul><ul><li>Therefore 2 molecules of ATP are gained </li></ul>
  12. 13. Energy of Glycolysis
  13. 14. The Role of NAD in Glycolysis <ul><li>During the conversion of glucose to pyruvic acid , hydrogen is released </li></ul><ul><li>This hydrogen is picked up by a coenzyme, nicotinamide adenine dinucleotide (NAD) </li></ul><ul><li>NAD is a hydrogen acceptor </li></ul><ul><li>When it accepts hydrogen, becomes NADH 2 </li></ul>
  14. 15. Summary of Glycolysis - Investment
  15. 16. Summary of Glycolysis - Payoff
  16. 17. Energy of Fermentation <ul><li>As a result of fermentation, each molecule of glucose yields 2 molecules of ATP </li></ul><ul><li>These ATP molecules come from glycolysis </li></ul><ul><ul><li>Fermentation produces no ATP beyond glycolysis </li></ul></ul><ul><li>It removes pyruvic acid, and recycles NAD, which allows glycolysis to continue, producing ATP </li></ul>
  17. 18. Alcoholic Fermentation <ul><li>Pyruvic acid from glycolysis combines with H from NADH 2 to produce ethyl alcohol </li></ul><ul><li>  2CH 3 COCOOH + 2NADH 2  2CH 3 CH 2 OH + 2CO 2 + 2NAD </li></ul><ul><ul><li>CO 2 is a waste product </li></ul></ul>
  18. 19. Alcoholic Fermentation Pathway
  19. 20. Lactic Acid Fermentation <ul><li>Pyruvic acid combines with H from NADH 2 to produce lactic acid: </li></ul><ul><li>2CH 3 COCOOH + 2NADH 2  2CH 3 CHOHCOOH + 2NAD </li></ul><ul><li>Unlike alcoholic fermentation, no CO 2 is given off </li></ul><ul><li>Occurs in human cells when there is not enough O 2 available for aerobic respiration </li></ul>
  20. 21. Lactic Acid Fermentation Pathway
  21. 22. Uses of Lactic Acid Fermentation <ul><li>During strenuous exercise glycolysis occurs at a high rate </li></ul><ul><li>Pyruvic acid is produced rapidly </li></ul><ul><li>Muscle cells may not receive enough O 2 to process pyruvic acid through aerobic respiration </li></ul><ul><li>Therefore muscles produce lactic acid which permits glycolysis to continue to supply ATP to your muscles </li></ul><ul><li>When lactic acid builds up, your muscles ache </li></ul><ul><li>O 2 you take in from heavy breathing helps convert lactic acid back to pyruvic acid </li></ul>
  22. 23. Cellular Respiration <ul><li>Most cells produce ATP by breaking the energy containing bonds of glucose in the presence of oxygen </li></ul><ul><li>Production of ATP this way = Respiration </li></ul><ul><li>Uses O 2 to break sugars down to CO 2 & H 2 O </li></ul><ul><ul><li>Not the same as breathing </li></ul></ul><ul><ul><li>provides O 2 , but otherwise quite different </li></ul></ul><ul><li>This process occurs in the many mitochondria of each cell </li></ul>
  23. 24. The Process of Cellular Respiration <ul><li>C 6 H 12 O 6 + 6 O 2  6 CO 2 + 6 H 2 O + energy </li></ul><ul><li>(sugar) (ATP) </li></ul><ul><li>Two stages of Cellular Respiration: </li></ul><ul><ul><li>Anaerobic </li></ul></ul><ul><ul><ul><li>without oxygen </li></ul></ul></ul><ul><ul><li>Aerobic </li></ul></ul><ul><ul><ul><li>with oxygen </li></ul></ul></ul>
  24. 25. Cellular Respiration Overview
  25. 26. Anaerobic Stage <ul><li>The anaerobic stage of cellular respiration is glycolysis , the same pathway used in fermentation </li></ul><ul><li>This part of cellular respiration occurs in the cytoplasm </li></ul><ul><li>Recall the energy budget for glycolysis: </li></ul><ul><ul><li>One molecule of glucose is split into two molecules of a three carbon compound called pyruvic acid </li></ul></ul><ul><ul><li>2 molecules of ATP provide the energy to split the glucose molecule </li></ul></ul><ul><ul><li>When glucose splits, it releases enough energy to form 4 molecules of ATP from ADP + P </li></ul></ul><ul><ul><li>Therefore 2 molecules of ATP are gained </li></ul></ul>
  26. 27. Energy of Glycolysis
  27. 28. Aerobic Stage <ul><li>After glycolysis , the chemical bonds of pyruvic acid are broken down in a series of chemical reactions </li></ul><ul><li>These occur in the mitochondria and require O 2 </li></ul><ul><li>The aerobic stage has two parts: </li></ul><ul><ul><li>The Citric Acid Cycle </li></ul></ul><ul><ul><li>The Electron Transport Chain </li></ul></ul>
  28. 29. Pyruvate Forms Acetyl CoA
  29. 30. The Citric Acid Cycle <ul><li>Steps to break down pyruvic acid : </li></ul><ul><li>In the presence of O 2 , pyruvic acid breaks down to acetic acid and CO 2 </li></ul><ul><ul><li>CO 2 is released as waste </li></ul></ul><ul><li>Acetic acid combines with coenzyme A  acetyl CoA </li></ul><ul><ul><li>This step also forms NADH 2 from NAD </li></ul></ul><ul><li>Acetyl CoA enters the citric acid cycle and combines with a 4 carbon compound to produce citric acid </li></ul><ul><li>As the cycle continues, citric acid is broken down in a series of steps, back to the original 4 carbon compound </li></ul>
  30. 31. Energy from the Citric Acid Cycle <ul><li>For each molecule of acetyl CoA that enters the cycle, 8 atoms of H are released. </li></ul><ul><li>These hydrogen atoms are trapped by NAD , forming NADH 2 . </li></ul><ul><li>Therefore, each turn of the cycle yields 4 NADH 2 </li></ul>
  31. 33. The Electron Transport Chain <ul><li>NADH 2 releases the hydrogen atoms trapped during glycolysis & the citric acid cycle </li></ul><ul><ul><li>Therefore NADH 2 becomes NAD again </li></ul></ul><ul><li>Electrons contained in the H atoms pass through a series of coenzymes which are electron acceptors. </li></ul><ul><li>Each time an electron moves from one acceptor to another, an electron is released </li></ul><ul><li>The electron released is used to form molecules of ATP from ADP + P </li></ul><ul><li>This whole process = electron transport chain </li></ul>
  32. 34. Oxygen & The Electron Transport Chain <ul><li>The last part of the chain is the electron acceptor, oxygen </li></ul><ul><li>Electrons combine with oxygen & hydrogen to form H 2 O, which is released as a byproduct </li></ul>
  33. 35. Chemiosmosis <ul><li>The process of formation of ATP during the ETS of aerobic respiration as the result of a pH gradient across the membrane of the cristae in the mitochondria = chemiosmosis </li></ul><ul><li>Steps: </li></ul><ul><ul><li>H + ions from the matrix are pumped into the space between the cristae and the outer membrane. </li></ul></ul><ul><ul><li>A H + gradient develops between the inside and outside of the cristae </li></ul></ul><ul><ul><li>This pH differential creates free energy </li></ul></ul><ul><ul><li>H + pass back across the membrane through F1 </li></ul></ul><ul><ul><li>O 2 is the final H + / electron acceptor producing H 2 O </li></ul></ul>
  34. 36. Picturing Chemiosmosis
  35. 37. Cellular Respiration Summary <ul><li>Thus for every molecule of glucose that is broken down by glycolysis and respiration, 38 molecules of ATP are formed </li></ul><ul><ul><li>Used 2 ATP to begin the process  Therefore 36 ATP gained </li></ul></ul>

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