BIOL 1441 1st Edition Lecture 13 Outline of Last Lecture I Osmoregulation a With cell walls II Facilitated diffusion III Active transport IV Membrane potential V Electrochemical gradient VI Electrogenic pump Outline of Current Lecture I Metabolism a Metabolic pathways b Metabolic enzymes II Forms of energy III Laws of energy transformation IV 1st law of thermodynamics V 2nd law of thermodynamics VI Free energy Current Lecture I Metabolism a All the chemical reactions in an organism at one time These notes represent a detailed interpretation of the professor s lecture GradeBuddy is best used as a supplement to your own notes not as a substitute II i Metabole change b Metabolism manages the matter energy resources of the cell c Thousands of chemical reactions occurring in any cell at one time d These reactions intersect into metabolic pathways e Metabolic Pathways i Begins with a specific molecule it is altered in a series of steps resulting in a specific product ii Each step is catalyzed by a specific enzyme f Metabolic Enzymes i Mechanisms that regulate enzymes catalyzing the metabolic pathway ii These balance supply demand iii Avert deficits or surpluses of cellular molecules iv Catabolic pathways release energy HIGH LOW 1 Break down complex molecules into simpler compounds 2 Cellular respiration breaks down glucose 3 Catabolism downhill 4 SPONTANEOUS v Anabolic pathways consume energy LOW HIGH 1 Build complex molecules from simpler ones 2 Protein synthesis from amino acids 3 Anabolism uphill 4 REQUIRES ENERGY BECAUSE NOT NATURAL WAY OF MOVEMENT Forms of Energy a EnergyV E the capacity to cause change i Some energy can perform work rearrange matter b Work move matter against opposing forces gravity i Examples contract muscles active transport c Exists in various forms cells need to transform energy from one form to another to perform the functions of life i Solar thermal chemical electrical mechanical d Kinetic energy energy associated with motion i Heat thermal energy energy associated with random movement of atoms or molecules ii Moving objects can perform work by transferring motion to other matter iii Pedal a bike moving legs e Potential energy energy that matter possesses because of its location or structure i Location concentration gradient ii Structure glucose ATP lots of energy to hold molecules together iii Chemical Energy energy available for release in a chemical reaction f Molecules store energy due to arrangement of their atoms i Glucose is a high energy molecule III IV V ii Broken down into simpler molecules arrangement requires less energy excess energy is released The Laws of Energy Transformation a Thermodynamics study of energy transformations i System describes the matter under study ii Surroundings everything outside the system b Closed system isolated from its surroundings i Nothing being exchanged ii liquid in a thermos bottle iii EVENTUALLY REACHES EQUILIBRIUM c Open system energy matter can be transferred between the system and its surroundings i Exchanging with surroundings all living organisms ii organisms absorb energy from surroundings release heat and metabolic waste products iii NEVER REACHES EQUILIBRIUM DOING WORK d Two laws that govern energy transformations First Law of Thermodynamics a Energy can be transferred transformed but it cannot be created or destroyed b The Principle of Conservation of Energy i Energy of universe is constant Second Law of Thermodynamics a Every time energy is transferred transformed most of it becomes unusableunavailable to do work i A BIG CHUNK IS LOST AS HEAT b Small fraction of the food you eat is transformed into usable energy most is lost as heat to your surroundings c The only use for heat in a living cell temperature is uniform is warming an organism i Crowded room gets hot lots of chemical rxn s occurring d Every energy transfer transformation increases the entropy disorder of the universe i Entropy S measure of randomness or disorder e There is an unstoppable trend toward randomization of the universe as a whole f Increased entropy evident in the physical disintegration of systems organized structure i Building falls apart unmaintained ii Your room gets messy g Increasing entropy in the universe less apparent i Appears as increasing amounts of heat ii Less ordered forms of matter less structured more random h LOW DECREASED ENTROPY VERY ORGANIZED HIGH ENERGY UNSTABLE i HIGH INCREASED ENTROPY CHAOTIC LOW ENERGY STABLE VI j IN BIOLOGY ENTROPY IS CONSIDERED AS HEAT k Why do certain processes in biology occur i For a process to occur on its own without input of energy it must increase the entropy of the universe 1 Breaking down or downhill reaction ii Spontaneous process no input of energy i e water flows down hill iii Nonspontaneous process cannot occur on its own needs energy added to the system 1 Water being pumped uphill l Biological Order and Disorder i Living systems increase the entropy of their surroundings BY GIVING OFF HEAT ii Organisms break down ordered forms of matter and energy release energy iii Cells also create ordered structures from less ordered materials input energy into system Free Energy a Gibbs free energy of a system measures the portion of a system s energy that can perform work when temperature and pressure are uniform throughout the system living cell b Free Energy Change DG i D delta change c Free energy G energy that can do work when temperature and pressure are uniform d Change in free energy G is related to the change in enthalpy H and change in entropy S i Enthalpy total amount of energy that you start with e Free Energy Change DG f Enthalpy change in total energy H g Entropy measure of disorder S h G H S i Every spontaneous process decreases that system s free energy i Lose it high low j Energy that can do work k Water flows down hill losing energy i G Gfinal state Ginitial state l Spontaneous processes are negative loss of free energy lost for that system BUT used elsewhere i Taking it away from that system m Final state has LESS free energy less likely to change more stable i Negative DOESN T make it a smaller number just the amount of energy being taken away n Only processes with a negative G are spontaneous positive or zero never spontaneous o Spontaneous process i Total energy enthalpy H must decrease or ii Disorder entropy S must increase 1 Or both p Free Energy Stability Equilibrium i Free energy measure of a system s instability 1 Tendency to change to a more stable state