BIOLOGY 111 1st Edition Lecture 9 Outline of Last Lecture I Microtubules II Microfilaments III Intermediate Filaments IV Membrane Structure and Function Outline of Current Lecture I Osmosis II Tonicity III Osmoregulation IV Metabolism V Gibbs Free Energy Current Lecture Osmosis The diffusion of free water across a selectively permeable membrane Water moves from an area of low solute to an area of high solute Water moves from an area of high concentration to an area of low concentration Tonicity the ability of a solution to cause a cell to gain or lose water Hypotonic solution The solute concentration is lower outside of the cell than inside Water goes inside the cell Turgid is very firm Normal for plants Hypertonic solution The solute concentration is higher outside of the cell than inside Water rushes outside of the cell Plasmolyzed causes wilting 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 Isotonic solution The solution concentration is equal on inside and outside of cell Flaccid means limp Osmoregulation the control of water balance necessary for adaption and survival Passive Transport moves substances with their concentrating gradient Active Transport moves substances against their concentration gradient Because it goes against it requires work which requires energy in the form of ATP Electrogenic pumps transport protein that generates a voltage across a membrane Sodium potassium pump animal cells Proton pump plants fungi and bacteria these two types of electrogenic pumps do the same thing just differ in structure Co Transport uses energy from a favorable gradient to drive transport against an unfavorable gradient These are extremely specific to their particle glucose H cotransporter will only carry glucose and Sucrose H cotransporter will only carry sucrose Phagocytosis a cell engulfs a particle by wrapping itself around it and packaging it within a food vacuole Pinocytosis the cell gulps droplets of extracellular fluid into tiny vesicles Receptor mediated Endocytosis enables the cell to acquire bulk quantities of specific substances by inward budding vesicles containing proteins with receptor sites specific to the molecules being taken in Chapter 8 Metabolism is the totality of an organism s chemical reactions consisting of catabolic and anabolic pathways which manage the material and energy resources of an organism Catabolic pathways release energy by breaking down complex molecules into simpler Anabolic pathways consume energy by building complex molecules from simpler ones Energy is the capacity to cause change and types include potential kinetic chemical and heat Potential energy is more unstable while Kinetic energy is more stable Thermodynamics is the science of energy transformations 1st law of thermodynamics conservation of energy energy cannot be created nor destroyed 2nd law of thermodynamics every transformation of energy is accompanied by increase in entropy disorder Every process in cell increases total entropy disorder making less energy available to do work in the future it is a continuous process never reaching equilibrium Eventually all usable forms of energy become heat which cannot be converted to any other form of energy Spontaneous reactions occur without energy input Spontaneous reactions increases total energy Gibbs Free Energy G refers to the amount of energy actually available to break and subsequently form other chemical bonds G H T S The change in free energy G predicts whether the reaction is spontaneous or not Only processes with negative G are spontaneous If the products of a reaction have less potential energy than the reactants then the reaction releases energy and is exergonic and spontaneous If the products of a reaction have more potential energy than the reactants then the reaction requires energy and is endergonic and not spontaneous