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Energy!!

Energy!!. What is energy?. Energy is the capacity to do work Energy is measured in kcals or joules. What is the difference between kinetic and potential energy?. Potential Energy – stored energy Stored in chemical bonds, chemical gradients Kinetic energy – energy of movement

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Energy!!

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  1. Energy!!

  2. What is energy? • Energy is the capacity to do work • Energy is measured in kcals or joules

  3. What is the difference between kinetic and potential energy? • Potential Energy – stored energy • Stored in chemical bonds, chemical gradients • Kinetic energy – energy of movement • Ex: Heat energy or Light Energy

  4. What is metabolism? Anabolic reactions? Catabolic Reactions? • Metabolism is the sum of all of the chemical reactions occurring in the body at the same time • Anabolic reactions (synthesis) link simple molecules to form more complex molecules • Catabolic reactions (hydrolysis) break down complex molecules into simpler molecules

  5. Why are anabolic and catabolic often coupled in living organisms? • Catabolic reactions release energy that can be used to drive anabolic reactions • They work TOGETHER

  6. The Laws of Thermodyamics

  7. The first law of thermodynamics • Energy cannot be created or destroyed in a reaction; It can only be transformed

  8. The second law of thermodynamics • When energy is transformed from one form to another, some of the energy becomes unusable • Unusable energy increases the amount of disorder in the universe (entropy)

  9. What is entropy (S)? Which law of thermodynamics applies to the amount of entropy? • Entropy is the amount of disorder or randomness in a system • Ex: Your messy room • 2nd Law

  10. For each of the following examples, is entropy increasing or decreasing? • Hydrolysis of proteins into amino acids • Synthesis of glycogen from glucose • Transcription of DNA into RNA • Digestion of a cheeseburger

  11. What is free energy (G)? • The amount of usable energy capable of doing work

  12. Chemical reactions either release free energy or require free energy • Exergonic reactions release free energy (from covalent bonds) and therefore are spontaneous reactions • Ex: Cellular Respiration

  13. Chemical reactions either release free energy or require free energy • Endergonic reactions require an input of energy and therefore are not spontaneous • These reactions form products that have high potential energy (stored) • Ex: Photosynthesis

  14. Gibbs Free Energy Equation In any system: Total energy = usable energy + unusable energy enthalpy (H) = free energy (G) + entropy (S) or H = G + TS (T = absolute temperature) G = H – TS

  15. Gibbs Free Energy Equation ΔG = ΔH – TΔS • If ΔG is negative, free energy is released (reaction will occur spontaneously and is exergonic) • If ΔG is positive, free energy is consumed (reaction will not occur spontaneously and is endergonic) If free energy is not available, the reaction does not occur.

  16. Complete the following chart Energy Energy Time Time

  17. What is the source of energy in cells used to drive endergonic reactions? • ATP!

  18. Describe the structure of ATP • Nucleoside • Adenine Base • Ribose Sugar • 3 phosphate Groups Which form has more energy stored: ATP or ADP or AMP?

  19. Why is ATP considered a “high energy” molecule? How does ATP store energy? • Captures and releases free energy • Releases a large amount of energy when hydrolyzed • Can phosphorylate other molecules to transfer energy (adding a phosphate group) • Energy is stored in the covalent bonds between phosphates

  20. Figure 5.12A_s2 Triphosphate ATP: Adenosine Phosphategroup P P P Adenine Ribose H2O Hydrolysis Energy P P P Diphosphate ADP: Adenosine

  21. ATP Cycle • ΔG = -7.3kcal when ATP -> ADP + Pi

  22. What is a coupled reaction? Energy Time

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