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BIOENERGETICS

BIOENERGETICS. Energy Flow. What is Bioenergetics?. The study of energy in living systems (environments) and the organisms (plants and animals) that utilize them. Energy. Required by all organisms May be Kinetic or Potential energy. Kinetic Energy. Energy of Motion

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BIOENERGETICS

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  1. BIOENERGETICS Energy Flow

  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 • Energyof position • Includes energy stored in chemical bonds

  6. Two Types of Energy Reactions

  7. Light Energy SUN photons (glucose) Endergonic Reactions • Chemical reaction that requires a net input of energy. • Absorbs free energy and stores it • Photosynthesis 6CO2 + 6H2O  C6H12O6 + 6O2

  8. Energy ATP (glucose) Exergonic Reactions • Chemical reactions that releases energy • Cellular Respiration C6H12O6 + 6O2  6CO2 + 6H2O+

  9. Metabolic Reactions of Cells

  10. What is Metabolism? • The sum totalof 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. energy ATP (glucose) Catabolic Pathway • Metabolic reactionswhich release energy(exergonic) by breaking downcomplex molecules in simpler compounds • Hydrolysis = add a water molecule to break apart chemical bonds • Cellular Respiration C6H12O6 + 6O2  6CO2 + 6H2O +

  13. light energy SUN (glucose) 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

  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

  21. Free Energy Changes

  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. Reaction Types Exergonic: chemical reactions with a net release of free energy. Endergonic: chemical reactions that absorb free energy from the surroundings.

  24. Exergonic/Endergonic

  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. adenine phosphate group P P P ribose ATP • Components: 1. adenine: nitrogenous base 2. ribose: five carbon sugar 3.phosphate group: chain of 3

  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 hydrolysisof ATP is coupled with the endergonic dehydration processby transferringaphosphate groupto another molecule. ATP H2O ADP + P H2O

  34. Adenosine triphosphate (ATP) P P P Hydrolysis (add water) + P P P Adenosine diphosphate (ADP) Hydrolysis of ATP ATP + H2OADP + P(exergonic)

  35. Hyrolysis is Exergonic Energy Used by Cells

  36. Adenosine triphosphate (ATP) P P P + P P P Adenosine diphosphate (ADP) Dehydration of ATP Dehydration(Remove H2O ADP + P ATP + H2O (endergonic)

  37. Dehydration is Endergonic Energy is restored in Chemical Bonds

  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.

  39. What Are Enzymes? • Most enzymes are Proteins (tertiary and quaternary structures) • Act as Catalyst to accelerates a reaction • Not permanently changed in the process

  40. Enzymes • Are specific for what they will catalyze • AreReusable • End in –ase -Sucrase -Lactase -Maltase

  41. How do enzymes Work? Enzymes work by weakening bonds which lowers activation energy

  42. Activation Energy • Energy needed to convert potential energy into kinetic energy. Activation Energy Potential Energy

  43. Without Enzyme With Enzyme Free Energy Free energy of activation Reactants Products Progress of the reaction Enzymes

  44. Enzyme Enzyme-Substrate Complex The substance (reactant) an enzyme acts on is the substrate Substrate Joins

  45. Enzyme Active Site Active Site • A restricted regionof an enzyme molecule which binds to the substrate. Substrate

  46. Models of How Enzymes Work 1. Lock and Key model 2. Induced Fit model

  47. Lock and Key Model • Substrate (key) fits to the active site (lock) which provides a microenvironment for the specific reaction.

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