Bio review ch.3

• In this chapter, you will learn how to analyze the role of metabolic processes in the functioning of and interactions between biotic and abiotic systems, assess the relevance of an understanding of cell biology and related technologies to your personal life and to the community, use appropriate terminology related to metabolism, conduct a laboratory investigation into the process of cellular respiration, explain the chemical changes and energy conversions associated with the processes of aerobic and anaerobic cellular respiration, use the laws of thermodynamics to explain energy transfer in the cell, and describe, compare, and illustrate the matter and energy transformations that occur during the process of cellular respiration
• Metabolism


  The sum of all chemical reactions that occur in the cell
• Metabolic pathway


  A sequential series of chemical reactions in living cells; each reaction is catalyzed by an enzyme
• Catabolism


  The process of breaking down compounds into smaller molecules to release energy
• Anabolism


  The process of using energy to build large molecules from smaller molecules
• Energy


  The capacity to do work
• Kinetic energy


  The energy of motion
• Potential energy


  Stored energy
• Bond energy


  Energy required to break (or form) a chemical bond
• Thermodynamics


  The science that studies the transfer and transformation of thermal energy (heat)
• Entropy


  A measure of disorder
• Free energy


  The energy available to do work
• Endergonic


  Requiring energy input
• Exergonic


  Releasing energy
• All living cells continuously perform thousands of chemical reactions to sustain life
• Metabolism refers to all the chemical reactions that change or transform matter and energy in cells
• Metabolic pathways are step-by-step sequences in which one substrate or more is changed into a product, and the product becomes a substrate for a subsequent reaction
• Enzymes catalyze each of these reactions in metabolic pathways
• The function of many metabolic pathways is to break down energy-rich compounds such as glucose and convert the energy into a form that the cell can use
• Catabolism is the process of breaking down compounds into smaller molecules to release energy
• Anabolism is the process of using energy to build large molecules
• Kinetic energy is energy of motion, while potential energy is stored energy
• Chemical energy is potential energy stored in the arrangement of the bonds in a compound
• When a chemical bond forms between two atoms, energy is released, and the amount of energy needed to break a bond is the same as the amount of energy released when the bond is formed
• The energy released from chemical reactions in living cells can include thermal energy, movement of compounds across cell membranes, contraction of a muscle, or emission of light
• Biological systems are considered to be open systems, meaning that the system and its surroundings can exchange matter and energy with each other
• The first law of thermodynamics states that energy cannot be created or destroyed, but it can be transformed from one type into another and transferred from one object to another
• The second law of thermodynamics states that during any process, the universe tends toward disorder
• Energy transformations proceed spontaneously to convert matter from a more ordered, less stable condition to a less ordered, more stable condition
• An untidy room will not spontaneously tidy itself
• Second Law of Thermodynamics

  During any process, the universe tends toward disorder
• Disorganized rooms do not spontaneously become organized
• The second law of thermodynamics can be stated simply as "entropy increases"
• When the universe formed, it held all the potential energy it will ever have. It has become increasingly more disordered ever since, with every energy exchange increasing the amount of entropy
• Organisms are highly ordered, but they are not closed systems. They use inputs of matter and energy to reduce randomness (decrease entropy) and thus stay alive
• The energy that keeps organisms alive comes ultimately from the Sun
• Free energy


  The energy available to do work in any system
• Endergonic reaction


  Chemical reaction that requires energy
• Exergonic reaction


  Chemical reaction that releases energy
• A spontaneous reaction can proceed very slowly