PHIS 206 1st Edition Lecture 2 Outline of Last Lecture Cell Structure I Physiology II History III Homeostasis Outline of Current Lecture I Cell Physiology II III IV V VI VII Organs Communication Methods Required Fluids How Solutes Behave Red Blood Cells Historical Background 17th Century How Do Large Molecules Get Across Current Lecture I Cell Physiology General Physiology old phrase Assumption if you know one cell s trick then you know the others We all carry a steady supply of red blood cells coming from 1 place Red blood cells not much more than a bag of hemoglobin Easy to measure volume of red blood cells cylinder ruler etc Sea urchin eggs spherical volume know the diameter 2 places to find them Cape Cod and Bay of Maples Nerve Cells A lot of similarities to a squid 1 nerve cell Easy to handle Can change fluid conveniently Larvae of Fruit Fly easy to see large nucleus and chromatin Studying Cells Assumption find an organism that is easy and study its cells workable method Evolution once Nature figures out a way process mechanism is preserved 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 Negative Is cell atypical to every organism Organs Communication Methods Required Pancreas delivers digestive juices to small intestine Simultaneous process continues to do while food enters the body III Fluids Intracellular ICF inside cells LOW concentrations of Na HIGH concentrations of K Extracellular ECF outside cells HIGH concentrations of Na 15 20 greater LOW concentrations of K Separated by cell membrane permeable to Na and K Conc of Na and K in ICF and ECF are only equal in DEATH IV How Solutes Behave simple diffusion random motion of molecules caused by heat Probability that water molecules move to red dye 0 Probability that red dye moves out water or100 When it becomes red the chance of red dye molecules moving is the same at equilibrium Diffusion rate is proportional to V conc of diffusion area Kelvin viscosity thickness mol size FIGG S EQUATION Not sensitive to temperature since temperature does not change much Slower than viscosity flow inverse relationship Membrane s thickness affects diffusion rate inverse relationship Bigger molecule slower diffusion Bigger membrane faster diffusion Red Blood Cells Diffusion by delivering oxygen from red blood cells to muscle cells FAST muscle cell Area of red cell rel to body is capillary containing red blood cell huge Temp is constant Mol size of O2 is small Thickness is small Smaller objects tend to have larger surface areas Rate of consumption will increase so rate of O 2 entering increases Automatically wind up w a nearly constant O2 concentration Things that will diffuse Soluble Small larger than glucose smaller than sucrose VI Historical Background 17th Century Early model Membranes must be layers of lipids Water molecules could fit through the membrane s pores if they were small VII How Do Large Molecules Get Across Facilitated diffusion proteins embedded in membranes can weakly bind certain molecules Graph Concentration Differences v Diffusion Rate x axis v y axis At same conc saturated carriers carrier proteins the side that the molecules attaches has higher concentrations NO ENERGY for facilitated or simple diffusion Only concentration matters Something going downhill does not require an Energy input
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