1 / 63

Understanding Metabolism and Energy Transformation

Discover the fascinating world of metabolism, the chemical processes that manage a cell's resources through catabolic and anabolic pathways. Learn about energy forms, laws of thermodynamics, and the vital role of enzymes in biological reactions.

arielk
Download Presentation

Understanding Metabolism and Energy Transformation

An Image/Link below is provided (as is) to download presentation Download Policy: Content on the Website is provided to you AS IS for your information and personal use and may not be sold / licensed / shared on other websites without getting consent from its author. Content is provided to you AS IS for your information and personal use only. Download presentation by click this link. While downloading, if for some reason you are not able to download a presentation, the publisher may have deleted the file from their server. During download, if you can't get a presentation, the file might be deleted by the publisher.

E N D

Presentation Transcript

  1. Chapter 8: An Introduction To Metabolism

  2. Metabolism • The totality of an organism’s chemical processes. • Concerned with managing the material and energy resources of the cell.

  3. Catabolic Pathways • Pathways that break down complex molecules into smaller ones, releasing energy. • Example: Respiration

  4. Anabolic Pathways • Pathways that consume energy, building complex molecules from smaller ones. • Example: Photosynthesis

  5. Energy • Ability to do work. • The ability to rearrange a collection of matter. • Forms of energy: • Kinetic • Potential • Activation

  6. Kinetic Energy • Energy of action or motion.

  7. Potential Energy • Stored energy or the capacity to do work.

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

  9. Energy Transformation • Governed by the Laws of Thermodynamics.

  10. 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.

  11. 2nd Law of Thermodynamics • Each energy transfer or transformation increases the entropy of the universe.

  12. Entropy • Measure of disorder.

  13. Summary • The quantity of energy in the universe is constant, but its quality is not.

  14. Question? • How does Life go against Entropy? • By using energy from the environment or external sources (e.g. food, light).

  15. Free Energy • The portion of a system's energy that can perform work.

  16. Free Energy G = H - TS G = free energy of a system H = total energy of a system T = temperature in oK S = entropy of a system

  17. Free Energy of a System • If the system has: • more free energy • it is less stable • It has greater work capacity

  18. Free Energy Changes

  19. 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.

  20. Chemical Reactions • Are the source of energy for living systems. • Are based on free energy changes.

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

  22. Exergonic/Endergonic

  23. Biological Examples • Exergonic - respiration • Endergonic - photosynthesis

  24. Cell - Types of Work • Mechanical - muscle contractions • Transport - pumping across membranes • Chemical - making polymers

  25. Cell Energy • Couples an exergonic process to drive an endergonic one. • ATP is used to couple the reactions together.

  26. ATP • Adenosine Triphosphate • Made of: - Adenine (nitrogenous base) - Ribose (pentose sugar) - 3 phosphate groups

  27. Adenine Phosphates Ribose

  28. Key to ATP • Is in the three phosphate groups. • Negative charges repel each other and makes the phosphates unstable.

  29. ATP • Works by energizing other molecules by transferring phosphate groups.

  30. ATP vs Food • ATP: • Renewable energy resource. • Unstable bonds • Food: • Long term energy storage • Stable bonds

  31. ATP Cycles • Energy released from ATP drives anabolic reactions. • Energy from catabolic reactions “recharges” ATP.

  32. ATP Cycle

  33. 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.

  34. Enzymes • Biological catalysts made of protein. • Cause the rate of a chemical reaction to increase.

  35. Chemical Reaction AB + CD AC + BD AB and CD are “reactants” AC and BD are “products”

  36. Enzymes • Lower the activation energy for a chemical reaction to take place.

  37. Enzyme Terms • Substrate - the material and enzyme works on. • Enzyme names: Ex. Sucrase - ase name of an enzyme 1st part tells what the substrate is. (Sucrose)

  38. Enzyme Name • Some older known enzymes don't fit this naming pattern. • Examples: pepsin, trypsin

  39. Active Site • The area of an enzyme that binds to the substrate. • Structure is designed to fit the molecular shape of the substrate. • Therefore, each enzyme is substrate specific.

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

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

  42. Induced Fit Model • Substrate “almost” fits into the active site, causing a strain on the chemical bonds, allowing the reaction.

  43. Substrate Active Site

  44. Enzymes • Usually specific to one substrate. • Each chemical reaction in a cell requires its own enzyme.

  45. Factors that Affect Enzymes • Environment • Cofactors • Coenzymes • Inhibitors • Allosteric Sites

More Related