BIOL 110 - Chapter 6: Introduction to Metabolism Fall 2024 PDF

BIOL 110 - Chapter 6: Introduction to Metabolism Readings: Chapter 6 1 Learning Outcomes Identify when free energy increases or decreases within a system and explain why this is in accordance with the first and second law of thermodynamics Describe ATP and how it fac...

BIOL 110 - Chapter 6: Introduction to Metabolism Readings: Chapter 6 1 Learning Outcomes Identify when free energy increases or decreases within a system and explain why this is in accordance with the first and second law of thermodynamics Describe ATP and how it facilitates reactions in biological systems Explain how enzymes increase reaction speed and Identify the mechanisms by which enzyme activity may be controlled and… suggest functional roles for these mechanisms within biological systems 2 Life Requires Energy All life requires energy Thermodynamics: the study of the energy of systems Bioenergetics: The study of how energy flows through living organisms 3  Metabolism All the chemical reactions performed by a living organism. Catabolic pathways: Breaks down molecules into smaller molecules which can be used to generate energy and chemical building blocks Anabolic pathways: Uses energy provided by catabolism to drive the synthesis of other molecules Is this heat wasted? What happens on a cold day? 4 Examples: Example of a/an ___________ pathway: Sucrose is broken down into monosaccharides The monosaccharides are broken down further until they are ultimately converted into CO2 and water This process is used to generate the energy currency ATP 5 Examples: Example of a/an ___________ pathway: After eating a donut, the glucose that we ingested is stored in the form of glycogen for later use Requires input of energy 6 Metabolism Citric Acid Cycle Conversion to Glycolysis Acetyl-CoA Example: The breakdown of glucose into CO2 7 Metabolism Metabolism can be complicated! 8 First…some energy fundamentals What is energy? “The capacity for doing work”. Britannica What kinds of energies do we have? 9 Forms of Energy Kinetic energy: energy associated with the movement of objects Potential energy: energy possessed by matter due to its location or spatial arrangement 10 Kinetic Energy Kinetic energy can take the form of thermal energy Thermal energy: kinetic energy associated with the random movement of atoms or molecules 11  Potential Energy Potential energy can be found in the arrangement of bonds between atoms Chemical energy: potential energy available for release in a chemical reaction 12 Thermodynamics Matter Energy Isolated system Open system Thermodynamics: study of energy transformations that occur within a “system” Do the following systems exchange matter and/or energy with their surroundings? Note: also a close system: exchange of energy but not matter 13 Laws of Energy Transformations Example: Do these water lilies create energy when they perform photosynthesis? The First Law of Thermodynamics: Energy can be transferred and or transformed, but it cannot be created or destroyed 14 The first law of thermodynamics How efficient is this process? 15 Energy Transformations and Efficiency 20-30% ~40% Energy transformations are not 100% efficient Think about driving…. What happens to the energy that isn’t converted into the new form? 16  Laws of Thermodynamics Entropy: a measure of disorder 1 2 Glucose + 6 O2  6 CO2 + 6 H2O + Heat 3 N2 (gas) + 3 H2 (gas)  2 NH3 (gas) Decide if entropy is increasing or decreasing in the these examples: The Second Law of Thermodynamics: Every energy transfer or transformation increases the entropy of the universe 17  Discuss: As living organisms, we are continually creating order. For example, the cells that we are composed of is far more ordered than if the molecules that the cells are composed of were separate and distinct. Have we broken the second law of thermodynamics? 18 Thermodynamics in practice Potential/chemical energy stored in fish  potential/chemical energy stored in bear  kinetic energy of bear  Heat is released  entropy increases 19 How much energy is available? Where does it originate? Will it ever run out? 20  Gibbs Free Energy (G) ΔG = Gfinal state – Ginitial state Δ = Change Gibbs Free Energy: the portion of a system’s energy that can perform work (at constant temperature and pressure) Often called “Free energy” Biologists usually focus on the change in free energy during a chemical reaction Tells us if a reaction is thermodynamically favourable Does not tell us that it will occur 21 Change in Gibbs Free Energy ΔG tells us whether a reaction will be spontaneous or not 22 Energy in Reactions endergonic ΔG>0 exergonic ΔG