A. Transport must occur because the cell must maintain mass action1.mass action- the ability to have continuous chemical transformation, so that there is never a stall in energyB. Requirements for transport1.Chemical disequilibrium- molecular gradient2.Electrical disequilibrium – polarized potentialC. Diffusion depends on Fick’s Law= (Surface area x [A] x Permeability)/ Resistance1.Surface area= amount of area for exchange2.[A]= the difference in concentration out vs. in3.Resistance= Thickness of membrane, distance plus the membrane hydophobicity, size and transporter availableD. Types1.Passive transport- does not require energya.moves toward equilibrium, disorganized and exergonicb. Simple Diffusion- molecule must be lipophilic (hydrophobic), water or quite small moves from an area of high concentration to low concentrationc. Osmosis- is specifically the movement of water from an area of high concentration to low concentrationd. Facilitated diffusion- does not require energy, but uses a protein channelLeak channels- simply open channels that small, charged molecules can pass throughGated Channels: 3 typesrate depends on size of molecules and transporters availablePrimary Active transport- requires energy, specifically ATP because it goes against the natural lawmoves away from equilibrium, organized and endergonicOnly work when ATP is present, and pump up chemical gradient so that there is a negative charge inside the cell and a positive charge outsideResting Membrane potential- electrical gradient that a cell must always have to avoid Equilibrium potential.If we run out of ATP or we run out of energy, we will reach an Equilibrium where no ions move, and will die, so we are always trying to avoid equilibrium and are always replenishing ATP and energy suppliesSecondary active transport (coupled transport)- one molecule moves down its gradient while another moves up itexergonic exchange linked with endergonic exchangethe ionic movement towards equilibrium liberates energy and allows for another molecule to move up its chemical gradientThe most common coupled ion is sodium, then Calcium, then Chloridethis conserves ATP for Synthetic reactionsOsmosis- movement of water molecules down its concentration gradientThe cell works towards IsoOsmotic conditions, or Homeostasis in the Fluid CompartmentsIntracellular fluid is about 70% of our bodies, while extracellular fluid is about 30% of the water in the body. In order to keep this present, the osmolarities must be equal (the amount of particle concentration with water) to make an isotonic atmosphereWhen there are more particles outside of the cell than inside of the cell- these are hyperosmotic conditionsWhen the membrane is impermeable to particles, water moves to equilabrate the Osmotic conditions and the water moves outside of the cell, causing the cell to shrivel or crenate.when the particles are permeable, the cell can move particles, particularly glucose into the cell to equilibrate the osmotic pressure, because bringing in any other ion would upset the balance of particles again.However if there is a condition where there are more particles concentrated inside the cell than outside the cell, the only response is to move water in which results in swelling of the cell- sometimes lysingBY 166 1st Edition Lecture 5Outline of Last Lecture I. ProteinsII. Membrane Physiology A. ImportanceB. StructureOutline of Current Lecture I. Transport across membraneA. Transport must occur for mass actionB. Requirements for transportC. Fick’s Law D. Types of TransportCurrent LectureI. Transport across membranesA. Transport must occur because the cell must maintain mass action1.mass action- the ability to have continuous chemical transformation, so that there is never a stall in energy B. Requirements for transport1.Chemical disequilibrium- molecular gradient2.Electrical disequilibrium – polarized potential C. Diffusion depends on Fick’s Law= (Surface area x [A] x Permeability)/ Resistance1.Surface area= amount of area for exchange2.[A]= the difference in concentration out vs. in3.Resistance= Thickness of membrane, distance plus the membrane hydophobicity, size and transporter available D. Types1.Passive transport- does not require energy a.moves toward equilibrium, disorganized and exergonicb. Simple Diffusion- molecule must be lipophilic (hydrophobic), water or quite small moves from an area of high concentration to low concentrationc. Osmosis- is specifically the movement of water from an area of high concentration to low concentrationd. Facilitated diffusion- does not require energy, but uses a protein channel Leak channels- simply open channels that small, charged molecules can pass through Move due to a chemical gradient and create an electrical gradientGated Channels: 3 typesLigand gate- chemical compound binds to open gateMechanical gate- physical pressure change to open gateVoltage gate- electrical (deals with change in polarity to open gate) rate depends on size of molecules and transporters availablePrimary Active transport- requires energy, specifically ATP because it goes against the natural law moves away from equilibrium, organized and endergonicOnly work when ATP is present, and pump up chemical gradient so that there is a negative charge inside the cell and a positive charge outsideResting Membrane potential- electrical gradient that a cell must always have to avoid Equilibrium potential.If we run out of ATP or we run out of energy, we will reach an Equilibrium where no ions move, and will die, so we are always trying to avoid equilibrium and are always replenishing ATP and energy suppliesSecondary active transport (coupled transport)- one molecule moves down its gradient while another moves up it exergonic exchange linked with endergonic exchangethe ionic movement towards equilibrium liberates energy and allows for another molecule to move up its chemical gradientThe most common coupled ion is sodium, then Calcium, then Chloridethis conserves ATP for Synthetic reactionsOsmosis- movement of water molecules down its concentration gradientThe cell works towards IsoOsmotic conditions, or Homeostasis in the Fluid Compartments Intracellular fluid is about 70% of our bodies, while extracellular fluid is about 30% of the water in the body. In order to keep this present, the osmolarities must be equal (the amount of particle concentration with water) to make an isotonic