Chpt. 12: Respiration

1. Chpt. 12: Respiration

2. Two types of respiration • External RespirationInternal respiration • is the process by which - is the controlled • organisms exchange gases release of energy • with their environment, from food. • e.g. occurs in lungs of • mammals, gills of fish.

3. Internal Respiration • controlled by enzymes. • normally involves the breakdown of glucose. • Energy that is released is trapped in the form of ATP: • Enzymes • Glucose Energy • (ATP) • Two types of internal respiration: • 1 Aerobic respiration. • 2 Anaerobic respiration.

4. Internal Respiration • Aerobic Respiration: is the release of energy from food within cells using oxygen. • Aerobes – living organisms which get their energy from aerobic respiration. • Brief explanation of aerobic respiration: • Energy stored in bonds of glucose molecule released and used to make ATP. • When ATP breaks down it supplies energy for all metabolic reactions in the cell, e.g. growth, production of new cells etc.

5. Internal Respiration Process of aerobic respiration can be represented by the balanced equation: Enzyme Glucose + Oxygen Carbon Dioxide + Water + Energy C6H12O6+6O2=6CO2+6H2O+Energy

6. Internal Respiration • Detailed explanation of aerobic respiration (O.L.): • Aerobic respiration is a two stage process: • Stage 1: • A process called glycolysis occurs in the cytosol (liquid in cell that surrounds the cell organelles) of the cell. • Glycolysis does not use oxygen – anaerobic process. • This process releases very little energy!!! • Glycolysis involves the splitting of glucose with 6 carbon molecules (C6) into two 3 carbon molecules (C3).

7. Internal Respiration • Stage 1: • At the same time a small number of ATP molecules are released. • Glycolysis: • Glucose two 3 carbon + small amount • molecules of energy • Note: stage 1 does not require oxygen and releases a small amount of energy!!!

8. Internal Respiration • Stage 2: • takes place in the mitochondria. • requires oxygen – aerobic respiration. • releases a lot of energy – it produces many ATP molecules. • This stage involves the complete breakdown of the two C3 molecules releasing a large amount of energy which is used to form a large amount of ATP molecules. • Carbon dioxide and water (contain very little energy) are the end products of stage 2 and subsequently aerobic respiration.

9. Internal Respiration Aerobic Respiration (O.L) Glucose (6 carbons) Two 3 – carbon molecules Carbon Dioxide and Water Stage 1 Anaerobic Small energy release Stage 2 Aerobic Large energy release

10. Internal Respiration • Anaerobic Respiration:is the release of energy from food without using oxygen. • Anaerobes:living organisms which get their energy from anaerobic respiration. • Brief explanation of anaerobic respiration: • occurs in the cytoplasm of the cell. • Glycolysis occurs breaking glucose (C6) into two • 3 – carbon molecules (C3) • This process releases very little energy!!! As a result this process is far less efficient process than aerobic respiration as glucose only partially broken down.

11. Internal Respiration Anaerobic respiration also known as fermentation Two types of fermentation Lactic Acid Fermentation Alcohol Fermentation

12. Internal Respiration • Lactic Acid Fermentation (Anaerobic Respiration): • occurs in some bacteria and fungi and in mammal muscle (humans) when it is short of oxygen. • This process can be represented by the equation: • Glucose 2 Lactic Acid + Small amount of energy

13. Internal Respiration • Alcohol Fermentation: • occurs in some bacteria, fungi (such as yeast) and in plants when they are deprived of oxygen. • This process can be represented by the equation: • Glucose 2 ethanol + 2 carbon dioxide • + • small amount of energy

14. Micro Organisms in Industrial Fermentation • Biotechnology (bioprocessing): is the production of useful products using living cells or their parts (cells, enzymes). • Biotechnology: involves the use of plants, animals and (mainly) micro-organisms. • Fermentation: in industry means the production of useful products by micro-organisms with or without the use of oxygen.

15. Industrial Fermentation – Production Method • Note:Bioreactor – vessel in which the biological reactions take place (pg. 117). • Micro – organisms – placed in bioreactor with suitable substrate. • Mixture – stirred or agitated to ensure contact between micro –organisms and substrate. • Foam – ,which is produced as a result of mixing, removed by foam breaker. • Culture Medium – liquid in which micro-organisms grow.

16. Industrial Fermentation – Production Method • Air is pumped into bioreactor to ensure adequate amount of oxygen dissolved in culture medium. • Sparger – forms small air bubbles which dissolve more readily into culture medium. • Other important factors during production: • 1. correct nutrients and micro – organisms. • 2. suitable temperature and pH. • 3. sterile environment.

17. Micro – Organisms used in Bio processing • Wide range of micro – organisms used to produce a huge range of useful chemicals and materials: • Fungi (yeast) - used in beer and wine production. • - used to supply carbon dioxide to cause dough to rise. • Bacteria and yeasts – manufacturing yoghurt, • cheese, vinegar, antibiotics. • Genetically altered bacteria, yeasts, fungi – solvents, amino acids, vitamins, drugs, food additives, enzymes.

18. Differences between Aerobic and Anaerobic Respiration

19. Detailed Study of Aerobic Respiration Higher Level

20. Stage 1:Glycolysis (small amount of energy produced) • occurs in cytosol of cell. • - enzymes speed up the process. • glucose which is a 6-carbon (C6) sugar is converted to • two 3-carbon (C3) sugars called pyruvic acid. • This is neutral molecule which may be found as the • negatively charged ion pyruvate. • No oxygen is required some of the energy released • forms 2 ATP molecules more of the energy is used to • form NADH.

21. Stage 1: Starch in plants Glycogen in animals Glucose (C6) ADP + P ADP + P NAD+ NAD+ ATP NADH ATP NADH PYRUVIC ACID C3 PYRUVIC ACID C3

22. Stage 1: Glucose (C6) 2 Pyruvic + 2ATP Acids (C3)

23. Stage 2: • In stage 2 a complex series of reactions take place • If oxygen is present the 2 pyruvic acids enter the • lumen(matrix) of the mitochondria and the following processes take • place: • Formation of acetyl coenzyme A • Pyruvic acid (3C) is converted to acetyl coenzyme A (2C) by the removal of CO2 and 2 e- • NAD+ is an electron acceptor and it will combine with the 2e- and a H+ proton to produce NADH: • NAD+ + 2e- + H+ NADH • Note: this NADH enters an electron transport system (ETC) • to produce H2O and ATP – discuss later

24. Stage 2: • B) Krebs Cycle • Acetyl coenzyme A now enters a series of reactions • called Krebs Cycle • Acetyl coenzyme A is broken down to CO2, H+ protons • and 2e- by a series of reactions. • 2e- and H+ combine with NAD+ to form NADH (goes • to ETC) • One ATP (phosphorylation) is made in each cycle.

25. Stage 2: B) Krebs Cycle Please be familiar with diagram representing this cycle

26. Pyruvic Acid (3C) NAD+ CO2 Electron Transport System 2e- NADH Acetyl coenzyme A (2C) NADH 2e- CO2 3NAD+ NAD+ 6e- CO2 3NADH Electron Transport System ATP + water ADP + P

27. Stage 2: • C) Electron Transport Chain (ETC) • Electron transport chains are located on the inner • membrane (cristae –folds) of the mitochondria. • Each electron transport chain consists of electron • carrier proteins in an orderly sequence in the cristae • of the mitochondria. • High energy electrons are passed from NADH to the • first of these protein molecules. • As electrons pass from molecule to molecule within • each chain they lose some of their energy.

28. Stage 2: • C) Electron Transport Chain (ETC): • Some of the energy released by the electrons is • used to form ATP (oxidative phosphorylation) and • the rest is lost as heat. • At the end of each chain , low energy electrons are • removed by combining with oxygen and hydrogen • to form water.

29. Stage 2: Electron Transport Chain (Oxidative Phosphorylation) H+ and NAD+ NADH (From Krebs Cycle) 2e- High energy electrons ADP + P Carrier Enzyme 1 ATP 2e- ADP + P Carrier Enzyme 2 ATP 2e- ADP + P Carrier Enzyme 3 ATP 2e- Low energy electrons 2e- + 2H+ + ½ O2 H2O

30. Summary of Aerobic Respiration • Stage 1: • Glycolysis - anaerobic respiration • - releases very little energy • - occurs in cytosol • Stage 2: • Krebs Cycle rxns and Electron Transport Chains • aerobic respiration • release large amount of energy • occurs in lumen and cristae of mitochondria

31. Anaerobic Respiration • Glycolysis (small amount of energy produced) • occurs in cytosol of cell. • glucose which is a 6-carbon (C6) sugar is converted to • two 3-carbon (C3) sugars called pyruvic acid. • This is neutral molecule which may be found as the • negatively charged ion pyruvate. • No oxygen is required some of the energy released • forms 2 ATP molecules more of the energy is used to • form 2 NADH molecules.

32. Anaerobic Respiration • In the absence of oxygen the two NADH molecules • break down to release 2e- and a proton. • The 2e- and the proton are then added to pyruvic • acid forming either: • - lactic acid (lactic acid fermentation) • - ethanol and CO2 (alcohol fermentation) • This addition of electrons is a process called Reduction

33. Krebs Cycle Diagram Krebs Cycle Theory

34. Glycolysis Diagram Glycolysis Theory

35. ETC Diagram ETC Theory