Transcript Slide 1
Chapter 8 Metabolism Overview Cell is a miniature CHM factory Inside this factory, Macromolecules are made and broken down Cellular Respiration powers the factory Extracts Energy stored in sugars (& other fuels) Cells use the Energy from cellular respiration to perform various types of work Active transport of solutes into the cell Bioluminescence Slide 2 of 50 Slide 3 of 50 Metabolism Metabolism – Totality of an organism’s chem. reactions Consists of 2 types of pathways Catabolic Pathway Breakdown of complex molecules into simpler compounds Release of energy Digestion, Cellular Respiration Anabolic Pathway Also called Biosynthetic pathways Simpler molecules Complicated molecules Consumes energy Polymerization, Synthesis, Photosynthesis Slide 4 of 50 Slide 5 of 50 Metabolic Pathways Begin with a specific molecule The input is altered in a series of defined steps Each step is catalyzed by an enzyme Mechanisms regulate enzymes Prevents molecular deficits & surpluses Creates a specific product Enzyme 1 A Enzyme 2 D C B Reaction 1 Enzyme 3 Reaction 2 Reaction 3 Slide 6 of 50 Slide 7 of 50 Slide 8 of 50 Slide 9 of 50 Questions How does 2nd law of thermodynamics explain diffusion? What is a catabolic process? What is an anabolic process? Which, catabolic or anabolic, requires energy? Which, catabolic or anabolic, produces energy? Slide 10 of 50 Energy Energy is the capacity to cause change… ATP in Biological systems Necessary for anabolic pathways In fact, necessary for all metabolic processes The work of life depends on the ability of cells to transform energy from one type to another Slide 11 of 50 Forms of Energy Kinetic Energy – energy of motion Thermal energy – random movement of particles or atoms produces this energy form Potential Energy – Inherent energy, 2 forms Gravitational PE – energy of position Chemical PE – energy contained in chemical bonds of a molecule Slide 12 of 50 Thermodynamics The study of energy transformations that occur in nature 1st Law of Thermodynamics Energy can neither be created nor destroyed Energy of the universe is constant Energy is just converted from one form to another 2nd Law of Thermodynamics Every natural process increases the entropy of the universe Entropy – Amount of disorder or randomness Slide 13 of 50 Gibb’s Free Energy Free energy – portion of system’s energy that is available to do work 2 Types of Reactions Exergonic – Free energy is released or used Spontaneous – Does not require energy input Endergonic – Free energy is required or absorbed Non-spontaneous – Requires energy input Slide 14 of 50 Energy Coupling Exergonic process is used to drive an endergonic process Primary form of exergonic process is the Hydrolysis of ATP (Adenosine TRIphosphate) 3rd phosphate group is removed Releases energy by bond breaking ATP ADP + P + ENERGY Slide 15 of 50 Slide 16 of 50 ATP Structure Slide 17 of 50 Phosphorylation When ATP is hydrolyzed, it transfers energy to the process that is coupled with it Uses enzyme to ensure successful coupling Along with energy the coupled molecule also receives a phosphate group Called Phosphorylation Hence if a molecule is phosphorylated it has gained energy Slide 18 of 50 ATP is recycled in Metabolism Slide 19 of 50 Slide 20 of 50 Questions 1. What is the definition of energy? 2. How is an enzyme different from a catalyst? 3. What do enzymes do? 4. Chemical energy is derived from what feature of molecules? Slide 21 of 50 Questions (Page 2) 5. What does the 2nd law of thermodynamics say? 6. Dehydration synthesis is endergonic or exergonic? Why? 7. Hydrolysis is endergonic or exergonic? Why? 8. How does ATP release energy? Slide 22 of 50