BIOL 1441 1st Edition Lecture 13 Outline of Last Lecture I. Osmoregulation a. With cell wallsII. Facilitated diffusionIII. Active transportIV. Membrane potentialV. Electrochemical gradientVI. Electrogenic pumpOutline of Current Lecture I. Metabolisma. Metabolic pathwaysb. Metabolic enzymesII. Forms of energyIII. Laws of energy transformationIV. 1st law of thermodynamicsV. 2nd law of thermodynamicsVI. Free energyCurrent LectureI. Metabolisma. All the chemical reactions in an organism at one timeThese 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.i. Metabole- changeb. Metabolism manages the matter & energy resources of the cellc. Thousands of chemical reactions occurring in any cell at one timed. These reactions intersect into metabolic pathways. e. Metabolic Pathwaysi. Begins with a specific molecule, it is altered in a series of steps, resulting in a specific productii. Each step is catalyzed by a specific enzymef. Metabolic Enzymesi. Mechanisms that regulate enzymes catalyzing the metabolic pathwayii. These balance supply & demandiii. Avert deficits or surpluses of cellular moleculesiv. Catabolic pathways - release energy (HIGH  LOW)1. Break down complex molecules into simpler compounds2. Cellular respiration- breaks down glucose3. Catabolism “downhill”4. SPONTANEOUSv. Anabolic pathways -consume energy (LOW  HIGH)1. Build complex molecules from simpler ones2. Protein synthesis from amino acids3. Anabolism “uphill”4. REQUIRES ENERGY BECAUSE NOT NATURAL WAY OF MOVEMENTII. Forms of Energya. EnergyV(E)- the capacity to cause changei. 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 lifei. Solar, thermal, chemical, electrical, mechanicald. Kinetic energy -energy associated with motioni. Heat (thermal energy)- energy associated with random movement of atoms or moleculesii. Moving objects can perform work by transferring motion to other matteriii. Pedal a bike, moving legse. Potential energy -energy that matter possesses because of its location or structurei. Location= concentration gradientii. Structure= glucose; ATP- lots of energy to hold molecules togetheriii. Chemical Energy- energy available for release in a chemical reactionf. Molecules store energy due to arrangement of their atomsi. Glucose is a high energy moleculeii. Broken down into simpler molecules- arrangement requires less energy, excess energy is releasedIII. The Laws of Energy Transformationa. Thermodynamics- study of energy transformationsi. System- describes the matter under studyii. Surroundings- everything outside the systemb. Closed system- isolated from its surroundingsi. Nothing being exchangedii. liquid in a thermos bottleiii. EVENTUALLY REACHES EQUILIBRIUMc. Open system- energy & matter can be transferred between the system and its surroundingsi. Exchanging with surroundings- all living organismsii. organisms absorb energy from surroundings & release heat and metabolic waste productsiii. NEVER REACHES EQUILIBRIUM-DOING WORKd. Two laws that govern energy transformationsIV. First Law of Thermodynamicsa. Energy can be transferred & transformed, but it cannot be created or destroyedb. The Principle of Conservation of Energyi. Energy of universe is constantV. Second Law of Thermodynamicsa. Every time energy is transferred/transformed, most of it becomes unusable- unavailable to do work i. A BIG CHUNK IS LOST AS HEATb. 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 occurringd. Every energy transfer/transformation increases the entropy (disorder) of the universei. Entropy (S)- measure of randomness or disordere. There is an unstoppable trend toward randomization of the universe as a wholef. Increased entropy- evident in the physical disintegration of systems organized structurei. Building falls apart unmaintainedii. Your room gets messyg. Increasing entropy in the universe less apparenti. Appears as increasing amounts of heatii. Less ordered forms of matter (less structured, more random)h. LOW/DECREASED ENTROPY- VERY ORGANIZED/HIGH ENERGY/UNSTABLEi. HIGH/INCREASED ENTROPY- CHAOTIC/LOW ENERGY STABLEj. IN BIOLOGY ENTROPY IS CONSIDERED AS HEATk. 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 universe1. Breaking down or “downhill” reactionii. 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 system1. Water being pumped uphilll. Biological Order and Disorderi. Living systems increase the entropy of their surroundings BY GIVING OFF HEATii. 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)VI. Free Energya. 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, DGi. D (delta) ® change c. Free energy (G)- energy that can do work when temperature and pressure are uniformd. Change in free energy (∆G) is related to the change in enthalpy (∆H) and changein entropy (∆S)i. Enthalpy: total amount of energy that you start withe. Free-Energy Change, DGf. Enthalpy- change in total energy (∆H )g. Entropy- measure of disorder (∆S)h. ∆G = ∆H - ∆Si. Every spontaneous process decreases that system’s free energyi. Lose it, highlowj. Energy that can do workk. Water flows down hill, losing energyi. ∆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 systemm. Final state has LESS free energy, less likely to change, more stablei. Negative DOESN’T make it a smaller number, just the amount of energy being taken awayn. Only processes with a negative ∆G are spontaneous (positive or zero, never spontaneous)o. Spontaneous