Aerobic Respiration vs Anaerobic Respiration vs Fermentation

By Aneeqa Rana

1. Aerobic respiration vs. Anaerobic respiration vs. Fermentation Presented by : Tayyaba khaliq (BMMG-17-13) Shabab zahra (BMMG-17-30) Aneeqa sadiq (BMMG-17- 44)

2. Introduction All living creatures require energy to live, replicate and to do their normal work.

3. T his energy comes from ATP . ATP is synthesized from the food we eat by the processes like Aerobic respiration Anaerobic respiration Fermentation

4. Aerobic respiration

5. Definition R espiration is a chemical process that breaks chemical bonds in glucose (organic compounds) , releasing stored energy and transferring some energy to ATP molecules while some energy is lost as heat. E quation for aerobic respiration 6O 2 +C 6 H 12 O 6 ➡️ 6CO 2 +6H 2 O+energy (ATP) oxygen+glucose ➡️ carbon dioxide+water +energy

6. Examples of aerobic bacteria Bacillus subtilis Anthrobacter Azotobacter Nocardia Pseudomonas aeruginosa

7. Stages There are 3 stages of aerobic respiration, each of which captures some of the chemical energy available in food molecules to convert it into ATP. Glycolysis Kreb’s cycle Electron transport chain

8. Glycolysis Process that takes place in the cytosol of the cytoplasm outside the mitochondria Breakdown glucose with the help of 2 ATP molecules and eventually releases 4 ATP molecules for a net gain of 2 ATP molecules.

9. Glycolysis is a fast process . Glycolysis alone DOES NOT require oxygen . It can supply chemical energy to cells when oxygen is NOT available .

10. End of glycolysis  90% of chemical energy from glucose still unused, locked in high-energy electrons of pyruvic acid . This energy is extracted by further steps following glycolysis.

11. Kreb’s cycle 2 nd stage of cellular respiration . Named after Hans Krebs , British biochemist in 1937 . Here pyruvic acid is broken dow n into carbon dioxide in a series of energy-extracting reaction . Citric acid is the 1 st compound formed in this series of reactions, so Krebs is sometimes called the Citric Acid Cycle .

12. Net Result I n glycolysis, one glucose molecule produces 2 pyruvic acid, which form 2 molecules of acetyl CoA . One glucose causes two turns of the Krebs cycle Produces : 8 NADH, 2 FADH 2 , 2 ATP, 6 CO 2

13. Uses for the products of the Krebs Cycle Carbon dioxide is exhaled (waste product) . H igh-energy electrons (stored in NADH & FADH 2 ) can be used to make huge amounts of ATP in the presence of oxygen by ETC .

14. Electron Transport chain Electron transport releases the energy your cells need to make the most of their ATP . In eukaryotes, electron transport chain is a series of carrier proteins located in the inner membrane of the mitochondrion . In prokaryotes, same chain is located in the cell membrane .

15. The chain functions as a chemical machine that uses energy released by the “fall” of electrons to pump hydrogen ions across the membrane . These ions store potential energy which makes ATP synthase to work. The overall energy coupling mechanism is termed as chemiosmosis .

16. Chemiosmosis Electrons from Krebs cycle are passed to electron transport chain by NADH & FADH 2 . At end of the chain an enzyme combines electrons from the electron chain with H + ions and oxygen to form water . Each time 2 high-energy electrons transport down the electron chain, their energy is used to transport H + ions across the membrane

17. H + ions build up in intermembrane space it is now positively charged, other side of membrane is negatively charged . Electrochemical gradient ( chemiosmotic gradient ) created for ATP synthase to work . A TP synthase harnesses the flow of H+ back into the matrix to phosphorylate ADP to ATP ( oxidative phosphorylation )

18. The Total ATP production of Aerobic CR

19. In absence of oxygen...

20. Anaerobic respiration

21. Anaerobic Cellular Respiration Many anaerobic bacteria, and muscle cells that run out of O 2 , can make ATP by using something other than oxygen as an electron acceptor ( nitrate , sulfate & carbon dioxide ). In anaerobic respiration, not all the ETC is used, so less ATP is produced.

22. CO 2 as an electron acceptor When CO 2 is used as an electron acceptor in anaerobic respiration, the product is either methane or acetic acid (depending on the organism ). M ethane produced in our gut (and released as farts) results from this process .

23. N ew study of people with GI symptoms , found that those with high levels of hydrogen (H) and methane (CH 4 ) gases in their breath also had higher body mass index (BMI) and % body fat .

24. Having both CH 4 and H in breath indicates presence of Methanobrevibacter smithii , a key methane-producing microbe (Archaea) in the human gut . I n addition to making methane, M. smithii scavenges hydrogen from other microbes, and these 2 actions appear to increase nutrient absorption and promote weight gain.

25. NO 3 - as an electron acceptor N itrate (NO 3 − ) can also be used as the terminal electron acceptor. Nitrate, like oxygen, has a high reduction potential. This process is widespread, and used by many members of Proteobacteria . Many denitrifying bacteria can also use ferric iron (Fe 3+ ) and different organic electron acceptors.

26. SO 2 -4 as an electron acceptor Sulfate reduction uses sulfate (SO 2 −4 ) as the electron acceptor, producing hydrogen sulfide (H 2 S) as a metabolic end product. Sulfate reduction is a relatively energetically poor process , and is used by many Gram negative bacteria found within the δ- Proteobacteria . It is also used in Gram-positive organisms related to Desulfotomaculum or the archaeon Archaeoglobus .

27. Fermentation

28. Fermentation When there is no final electron acceptor for the ETC , then electron transport can’t happen. F ermentation is an alternative system that allows glycolysis to continue without the other steps of cellular respiration . Not as energetically efficient as respiration . Produces only 2 ATP . ATP ATP

29. Types of fermentation There are two major types of fermentation on the basis of their product. Lactic acid fermentation Alcoholic fermentation

30. fermentation Alcoholic fermentation Lactic Acid fermentation yeast Alcohol evap. Muscle cramps Holes in bread b/c produced

31. LACTIC ACID FERMENTATION Performed by some fungi, some bacteria, and sometimes by our muscles. Products include cheese, yogurt, and very sore muscles!

32. Lactic Acid Fermentation An enzyme converts pyruvic acid into another 3-C compound called lactic aci d. Equation for lactic acid fermentation GLUCOSE → 2 LACTIC ACID C 6 H 12 O 6  → 2 C 3 H 6 O 3

33. The miracle of fermentation Involves the transfer of 2 H+ from NADH to pyruvic acid NADH is oxidized NAD+ is used in glycolysis

34. Muscle cells Normally our muscles do cellular respiration using O 2 supplied by our lungs and blood. When the oxygen supplied by the lungs and blood system can’t get there fast enough to keep up with the muscles’ needs, our muscles can switch over and do lactic acid fermentation. Body must get rid of the lactic acid and releases it by panting heavily (intake of oxygen)

35. Yogurt It is the presence of lactic acid in yogurt that gives it its sour taste .

36. Two main types of Lactic Acid Bacteria (Identified around the year 1900): Lactobacillus meaning “milk” and “rod” over 50 different species found on plants and in the digestive system of animals such as cows and humans.

37. Lactococcus meaning “milk” and “sphere” because of its shape found primarily on plants less common than lactobacillus

38. Traditional spontaneously fermented milks contain species that can reside in the human digestive tract: Lactobacillus fermentum , L . casei L . brevis L . plantarum ( from pick l ed vegetables) L . acidophilus

39. Alcoholic Fermentation Performed by yeast, some kinds of bacteria, & a few other microorganisms Products include CO 2 and Alcohol Used to make beer, bread and wine

40. Alcoholic Fermentation Converts pyruvic acid into ethyl alcohol Equation for Alcoholic fermentation GLUCOSE → 2 ETHANOL + 2 CARBON DIOXIDE C 6 H 12 O 6  → 2 C 2 H 5 OH + 2 CO 2

41. Step one CO2 is removed from pyruvic acid Leaving a 2-C compound Step two H+ are added to the 2-C compound to form ethyl alcohol H+ come from NADH Steps

42. Basic concept of beer and wine industry CO2 is a by product for wine and allowed to escape In beer, carbon dioxide creates the “carbonation”

43. Souring & Spoilage Different Results of Anaerobic Metabolism Souring : Fermentation of carbohydrates generates organic acids. S our cream, cheese, and yogurt are produced by the action of bacteria doing fermentation. Lactic-acid bacteria produces a sour flavor in curd.

44. Spoilage : Spoilage accurs when microbes use anaerobic respiration to break down proteins , releasing nitrogen and sulfur-containing organic compounds . A lso known as putrification . Anaerobic respiration of protein often produces foul smelling chemicals such as putrescine , cadaverine & hydrogen sulfide .

45. Conclusion