Bioenergetics.ppt
- 2. What is Bioenergetics? The study of energy in living systems (environments) and the organisms (plants and animals) that utilize them
- 3. Energy Required by all organisms May be Kinetic or Potential energy
- 4. Kinetic Energy Energy of Motion Heat and light energy are examples
- 5. Potential Energy Energy of position Includes energy stored in chemical bonds
- 6. Two Types of Energy Reactions
- 7. Endergonic Reactions Chemical reaction that requires a net input of energy. Absorbs free energy and stores it Photosynthesis 6CO2 + 6H2O C6H12O6 + 6O2 SUN photons Light Energy (glucose)
- 8. Exergonic Reactions Chemical reactions that releases energy Cellular Respiration C6H12O6 + 6O2 6CO2 + 6H2O+ ATP (glucose) Energy
- 10. What is Metabolism? The sum total of the chemical activities of all cells. Managing the material and energy resources of the cell
- 11. Two Types of Metabolism Catabolic Pathways Anabolic Pathways
- 12. Catabolic Pathway Metabolic reactions which release energy (exergonic) by breaking down complex molecules in simpler compounds Hydrolysis = add a water molecule to break apart chemical bonds Cellular Respiration C6H12O6 + 6O2 6CO2 + 6H2O + ATP (glucose) energy
- 13. Anabolic Pathway Metabolic reactions, which consume energy (endergonic), to build complicated molecules from simpler compounds. Dehydration synthesis = removal of a water molecule to bond compounds together Photosynthesis 6CO2 + 6H2O C6H12O6 + 6O2 Sun light energy (glucose)
- 14. Energy Coupling The transfer of energy from catabolism to anabolism Energy from exergonic reactions drive endergonic reactions and vice versa EX. Photosynthesis – cellular respiration cycle
- 15. Energy Transformation Governed by the Laws of Thermodynamics.
- 16. 1st Law of Thermodynamics Energy can be transferred and transformed, but it cannot be created or destroyed. Also known as the law of Conservation of Energy.
- 17. 2nd Law of Thermodynamics Each energy transfer or transformation increases the entropy of the universe. Entropy = a measure of disorder or randomness HEAT is energy in its most random state.
- 18. Summary The quantity of energy in the universe is constant, but its quality is not.
- 19. Free Energy The portion of a system's energy that can perform work. G = H - TS G = free energy of a system H = total energy of a system T = temperature in oK S = entropy of a system
- 20. Free Energy of a System If the system has: more free energy it is less stable It has greater work capacity Metabolic equilibrium = zero free energy so it can do no work DEAD CELL Metabolic disequilibrium = produces free energy to do work More unstable produces more free energy EX. Greater concentration/ temperature differences
- 22. Spontaneous Process If the system is unstable, it has a greater tendency to change spontaneously to a more stable state. This change provides free energy for work.
- 23. Chemical Reactions Are the source of energy for living systems. Are based on free energy changes. Exergonic: chemical reactions with a net release of free energy. Endergonic: chemical reactions that absorb free energy from the surroundings. Reaction Types
- 25. 3 main kinds of cellular work Mechanical - muscle contractions Transport - pumping across membranes Chemical - making polymers All cellular work is powered by ATP
- 26. Cell Energy Couples an exergonic process to drive an endergonic one. ATP is used to couple the reactions together.
- 27. Cellular Energy - ATP
- 28. ATP Components: 1. Adenine: nitrogenous base 2. Ribose: five carbon sugar 3.Phosphate group: chain of 3 ribose adenine P P P phosphate group
- 29. Adenosine Triphosphate Three phosphate groups- (two with high energy bonds Last phosphate group (PO4) contains the MOST energy All three phosphate groups are negatively charged (repel each other making it very unstable)
- 30. Breaking the Bonds of ATP Occurs continually in cells Enzyme ATP-ase can weaken & break last PO4 bond releasing energy & free PO4 Phosphorylated = a phosphate group attaches to other molecules making them more unstable and more reactive (energy boost to do work)
- 31. How does ATP work ? Organisms use enzymes to break down energy-rich glucose to release its potential energy This energy is trapped and stored in the form of adenosine triphosphate(ATP)
- 32. How Much ATP Do Cells Use? It is estimated that each cell will generate and consume approximately 10,000,000 molecules of ATP per second
- 33. Coupled Reaction - ATP The exergonic hydrolysis of ATP is coupled with the endergonic dehydration process by transferring a phosphate group to another molecule. H2O H2O
- 34. Hydrolysis of ATP ATP + H2O ADP + P (exergonic) Hydrolysis (add water) P P P Adenosine triphosphate (ATP) P P P + Adenosine diphosphate (ADP)
- 36. Dehydration of ATP ADP + P ATP + H2O (endergonic) P P P Adenosine triphosphate (ATP) P P P + Adenosine diphosphate (ADP) Dehydration (Remove H2O
- 38. ATP in Cells A cell's ATP content is recycled every minute. Humans use close to their body weight in ATP daily. No ATP production equals quick death.
- 40. FAD It derived from riboflavin, vitamin B2 They have function in oxidation and reduction reactions FAD is act as coenzyme for various enzymes like α- ketoglutarate dehydrogenase, succinate dehydrogenase, xanthine dehydrogenase, acyl co dehydrogenase . It exist in three different redox states, which are, 1. Quinone (FAD) - fully oxidized form 2.Semiquinone (FADH) -half reduced form 3.Hydroquinone (FADH2) - fully reduced form
- 41. STRUCTUREOFFAD Flavin adenine dinucleotide consists of two main portions An adenine nucleotide (adenosine monophosphate) A flavin mononucleotide It is bridged together through their phosphate groups. Riboflavin is formed by a carbon-nitrogen (C-N) bond between a isoalloxa zine and a ribitol.
- 42. STRUCTUREOFFAD
- 44. FAD can be reduced to FADH2 through by the addition of two H+ and two e-.
- 46. Basic Physical and Chemical Properties Based on the oxidation state, flavins take specific colors when in aqueous solution. FAD (fully oxidized) is yellow, FADH(half reduced) is either blue or red based on the pH, FADH2 the fully reduced form is colorless
- 48. Biosynthesis of FAD FAD plays a major role as an enzyme cofactor originating from riboflavin. Bacteria, fungi and plants can produce riboflavin, but other eukaryotes, such as humans, have lost the ability to make it. Humans must obtain riboflavin, also known as vitamin B2, from dietary sources. Riboflavin is generally absorbed in the small intestine and then transported to cells via carrier proteins.
- 49. FAD is synthesized in the cytosol and mitochondria and potentially transported where needed. Step 1 Riboflavin kinase (EC 2.7.1.26) adds a phosphate group to riboflavin to produce flavin mononucleotide. Step 2 FAD synthetase attaches an adenine nucleotide; both steps require ATP .
- 50. Biosynthesis
- 51. BiologicalFunctions andImportance • Catalyze difficult redox reactions such as dehydrogenation of a C-C bond to an alkene • FAD has a more positive reduction potential than NAD+ and is a very strong oxidizing agent. • FAD plays a major role as an enzyme cofactor • FAD-dependent proteins function in a large variety of metabolic pathways • Electron transport, role in production of ATP • The reduced coenzyme FADH2 contributes to oxidative phosphorylation in the mitochondria. FADH2 is reoxidized to FAD, which makes it possible to produce 1.5 equivalents of ATP.
- 52. DNA repair nucleotide biosynthesis FAD-dependent enzymes that regulate metabolism are glycerol-3-phosphate dehydrogenase (triglyceride synthesis) and xanthine oxidase involved in purine nucleotide catabolism beta-oxidation of fatty acids Redox flavoproteins that non-covalently bind to FAD like Acetyl-CoA-dehydrogenases which are involved in beta- oxidation of fatty acids amino acid catabolism catabolism of amino acids like leucine (isovaleryl- CoA dehydrogenase), isoleucine, (short/branched-chain acyl- CoA dehydrogenase), valine (isobutyryl-CoA dehydrogenase), and lysine Synthesis of other cofactors such as CoA, CoQ and heme groups.
- 53. EXAMPLES OF FAD DEPENDENT ENZYEMS
- 54. 54 • Flavin mononucleotide (FMN), or riboflavin-5′-phosphate, is a biomolecule produced from riboflavin (vitamin B2) by the enzyme riboflavin kinase and functions as the prosthetic group of various oxidoreductases, including NADH dehydrogenase, as well as cofactor in biological blue-light photo receptors. • During the catalytic cycle, a reversible inter-conversion of the oxidized (FMN), semiquinone (FMNH•), and reduced (FMNH2) forms occurs in the various oxidoreductases. FMN is a stronger oxidizing agent than NAD and is particularly useful because it can take part in both one- and two-electron transfers. • It is the principal form in which riboflavin is found in cells and tissues. It requires more energy to produce, but is more soluble than riboflavin. Flavin mononucleotide (FMN)