comparison of aerobiac and anaerobic respiration ppt.pptx

Lecture note

1. Almost all the ATP produced in cells is formed in the same way. It obviously involves ADP and Pi joining to form ATP and this requires an input of energy . The formation of ATP involves an enzyme called ATP synthase The ATP synthase is in one of the enzymes found membranes of mitochondrion & chloroplast . How is ATP produced in a cell ? The structure of ATP synthase ATP synthase is like a water wheel. When the rotor is spin by hydrogen ions passing through it, the energy of the spinning is used to activate sites in the catalytic knob that convert ADP and P i to ATP. In both photosynthesis and aerobic respiration, many of the reactions generate the hydrogen ions that will pass through the ATP synthase to produce ATP

2. Two types of metabolic reactions involved during energy production Anabolism larger molecules are made requires energy Eg . Photosynthesis Catabolism larger molecules are broken down releases energy Eg . Cellular Respiration How is ATP produced in a cell ?

3. There are two main pathways by which respiration can produce ATP: T he aerobic pathway ( aerobic respiration ) – this requires the presence of oxygen, and T he anaerobic pathway ( anaerobic respiration and fermentation ) – this can take place in the absence of oxygen How is ATP produced in respiration ?

4. Cellular Respiration 4 Before cells can use the energy in complex carbohydrates (a major source of energy for organisms), the large polymers are broken down into simple sugars such as glucose . Then , glucose is split even further to release energy. 8/17/2024 By: Asmamaw Menelih

5. Cellular Respiration 8/17/2024 By: Asmamaw Menelih 5

6. Cellular Respiration 6 8/17/2024 By: Asmamaw Menelih

7. Oxidative phosphorylation : oxygen dependent production of ATP Matrix : fluid in the mitochondrion in which the reactions of the Krebs cycle take place ATP synthase: enzyme involved in the formation of ATP Substrate level phosphorylation: when another molecule (substrate) is able to transfer a phosphate group directly to ADP ( ATP synthase enzyme is NOT involved in the formation of ATP) Respiratory substrates: organic molecules that can be respired such as glucose, fatty acids, amino acids etc phosphorylated nucleotide : the adding of one or more phosphate groups to a nucleotide molecule Decarboxylation: removing of carbon from a molecule Dehydrogenation: removing of hydrogen from a molecule Basic Concepts

8. Cellular Respiration 8 Glycolysis : " splitting sugars." one six-carbon molecule of glucose is broken into two molecules of the three-carbon compound pyruvate . ATP is produced from ADP and Pi, and nicotinamide adenine dinucleotide (NAD +) is reduced to form NADH. Cellular respiration occurs in 4 stages : 8/17/2024 By: Asmamaw Menelih

9. Cellular Respiration 9 Glycolysis: 3 . Citric Acid Cycle: 4 . Oxidative Phosphorylation: Cellular respiration occurs in 4 stages : 2. Pyruvate processing 8/17/2024 By: Asmamaw Menelih

10. Cellular Respiration 10 Glycolysis: 2. Citric Acid Cycle: Each acetyl CoA is oxidized to two molecules of CO 2 . More ATP and NADH are produced, and Flavin adenine dinucleotide (FAD ) is reduced to form FADH 2 . Cellular respiration occurs in 3 stages : 8/17/2024 By: Asmamaw Menelih 2. Pyruvate processing (Link Reaction):

11. Cellular Respiration 11 Glycolysis: 3 . Citric Acid Cycle: 4 . Oxidative Phosphorylation: Extracts energy from NADH & FADH 2 . Passes electrons from higher to lower energy states. Produces 32 or 34 molecules of ATP Cellular respiration occurs in 3 stages : 8/17/2024 By: Asmamaw Menelih 2. Pyruvate processing (Link Reaction):

12. Stages of Cellular Respiration 12 Glycolysis: G lycolysis , takes place in the cytoplasm. It does not take place inside the mitochondria because : The glucose molecule cannot diffuse through the mitochondrial membranes (it is a medium-sized molecule and is not lipid soluble) T here are no carrier proteins to transport the glucose molecule across the membranes . 8/17/2024 By: Asmamaw Menelih

13. Stages of Cellular Respiration 13 Glycolysis: Splitting glucose into two 3-carbon molecules of pyruvate in cytoplasm of cell . Does NOT require O 2. Two ATP are used to activate glucose Two electrons and one hydrogen ion are accepted by NAD + (nicotinamide adenine dinucleotide) resulting two NADH. Produced four ATP and gain net of two ATP. 8/17/2024 By: Asmamaw Menelih

14. 8/17/2024 By: Asmamaw Menelih 14 Glycolysis steps

15. At the end of glycolysis from a single Glucose Molecule: There is a net gain of two ATP ( two molecules are used initially and then four are produced). Two molecules of reduced NAD ( NADH) The molecules of pyruvate pass into the mitochondria through carrier molecules in the mitochondrial membrane. Summary of Glycolysis

16. Stages of Cellular Respiration 16 Pyruvate processing (Link Reaction): Each pyruvate is processed to release one molecule of CO 2 , and the remaining two carbons are used to form the compound acetyl CoA. The oxidation of pyruvate results in more NAD+ being reduced to NADH. 8/17/2024 By: Asmamaw Menelih

17. 8/17/2024 By: Asmamaw Menelih 17 One fate of pyruvate is that it enters to TCA cycle for complete oxidation. But there are intermediate processes that convert pyruvate to a acetyl coA . The enzyme complex converts pyruvate into Acetyl-CoA by the following chemical changes: Decarboxylation of pyruvate (loss of CO2) Formation of acetyl group Linkage of acetyl group to coenzyme A forming acetyl - CoA . Overall Summary of Link reaction pyruvate + CoA + NAD⇌ acetyl CoA + CO2 + reduced NAD Pyruvate processing (Link Reaction )

18. Stages of Cellular Respiration 18 Kreb’s Cycle : Occurs inside the mitochondrial “matrix”. The pyruvate molecules are transformed into acetyl CoA. Begins by the addition of a two-carbon acetyl group to a four-carbon molecule ( oxaloacetate ), forming a six-carbon molecule ( citric acid ) H atoms added to NAD and FAD to form NADH and FADH 2 . C and O atoms given off as ‘waste’ product CO 2 . 2 ATP produced . 8/17/2024 By: Asmamaw Menelih

19. 8/17/2024 By: Asmamaw Menelih 19 The TCA cycle Krebs's Cycle:

20. Summary of Krebs's Cycle Krebs cycle take place in the fluid matrix of the mitochondrion Acetyl coenzyme A (2C) reacts with oxaloacetate to form Citrate (6C). Citrate loses a carbon atom to form a five-carbon compound and CO2 is produced The five-carbon compound is then further decarboxylated to form a four-carbon compound and CO2 is again produced One molecule of ATP is also produced by substrate level phosphorylation The four-carbon compound undergoes several molecular transformations to form Oxaloacetate In several reactions in the cycle, reduced NAD and in one reaction, reduced FAD is produced

21. Summary of Krebs's Cycle

22. Stages of Cellular Respiration 22 Electron Transport : Occurs in the membrane of mitochondria. The process by which energy is transferred from NADH and FADH 2 to ATP. NADH and FADH 2 provide electrons and H+ to the mitochondria. The electrons move via an electron transport chain in the inner membrane of the mitochondrion. 8/17/2024 By: Asmamaw Menelih

23. Stages of Cellular Respiration 23 Electron Transport : The electrons end up in oxygen. Some hydrogen bonds with oxygen to make H 2 O as a waste product. G enerate 32 of the 36 ATP molecules produced from each glucose molecule!. 8/17/2024 By: Asmamaw Menelih

24. Stages of Cellular Respiration 24 Electron Transport : On the cristae, the following events take place : The hydrogen atoms carried by NADH and FADH2 are released and split into protons (hydrogen ions) and electrons The electrons pass along a series of electron carriers lose energy as they pass from one carrier to the next The molecules that act as electron carriers in the electron transport chain are: reduced NAD dehydrogenase (also a proton pump ) ubiquinone (also a proton pump), and cytochromes ( these are proteins that contain iron ) 8/17/2024 By: Asmamaw Menelih

25. Electron Transport :

26. Electron Transport : Oxidative phosphorylation takes place in the inner mitochondrial membrane . Reduced NAD and reduced FAD are passed to the electron transport chain. The hydrogens are removed from the two hydrogen carriers and each is split into its constituent proton (H+) and electron (e−). The energetic electron is transferred to the first of a series of electron carriers.

27. Electron Transport : Hydrogen carrier molecules Two molecules are important in this transfer process : Nicotinamide Adenine Dinucleotide ( NAD) Flavine Adenine Dinucleotide (FAD ) Both are coenzymes and are capable of accepting hydrogen ions. NAD + 2H ⇌ reduced NAD NAD + +2H ⇌ NADH + + H+

28. Electron Transport : Hydrogen carrier molecules pass protons into the mitochondrial matrix through protein channels in the inner membrane. The enzyme ATP synthase is associated with each channel. As the protons pass through the channel, their electrical potential energy is used to synthesis ATP in the process called chemiosmosis The sites of events of respiration in a cell

29. Summary Cellular Respiration 29 The actual yield of ATP per glucose ( 32 ATP) is lower than the theoretical calculation (38 ATP) because the proton motive force is used to drive other mitochondrial activities, such as the active transport of Pi into the mitochondrial matrix . 8/17/2024 By: Asmamaw Menelih 28 28

30. Summary Cellular Respiration 30 Theoretical Calculation 8/17/2024 By: Asmamaw Menelih Cellular Respiration.mp4

31. Anaerobic Respiration 31 Pyruvate is a pivotal metabolite in cellular respiration. If O 2 is not available to the cell, fermentation, an anaerobic process, occurs in the cytoplasm. During fermentation, glucose is incompletely metabolized to lactate, or to CO 2 and alcohol (depending on the organism). If O 2 is available to the cell, pyruvate enters mitochondria by aerobic process . Certain cells in our body can produce energy without oxygen- - muscle cells. 8/17/2024 By: Asmamaw Menelih

32. Anaerobic Respiration 32 An anaerobic process that reduces pyruvate to either lactate or alcohol and CO 2 . NADH passes its electrons to pyruvate. Alcoholic fermentation : carried out by yeasts, produces carbon dioxide and ethyl alcohol. Used in the production of alcoholic spirits and breads. Lactic acid fermentation: carried out by certain bacteria and fungi, produces lactic acid (lactate ). Used commercially in the production of cheese, yogurt, and sauerkraut. In mammalian red blood cells and in skeletal muscle 8/17/2024 By: Asmamaw Menelih

33. Anaerobic Respiration 33 8/17/2024 By: Asmamaw Menelih

34. Products of Fermentation 34 8/17/2024 By: Asmamaw Menelih

35. The immediate source energy for cells is ATP The full name for ATP is A denosine T ri- P hosphate ATP will release in energy in small amount with a single hydrolysis rxn and can be move around cells easily. ATP is important for chemical, transport and mechanical work of cells. ATP produced in similar way in all cells. i.e ADP+Pi =ATP The enzyme that catalyze ATP production is known as ATP Synthesase Cells can Produce ATP through cellular respiration The Four stages of cellular respiration are Glycolysis, link rxn , citric acid cycle and Oxidative phosphorylation Chapter Summary

36. Thank You!!