Membrane DynamicsTransport across membranes1. Direct2. Facilitated Diffusion3. Osmosis4. Ion Channel5. Active transport6. Exo and EndocytosisDiffusion is affected by…1. Concentration2. Distance3. Temperature4. C-S Area5. Molecular Size6. Lipid SolubilityFacilitated DiffusionGlucose Transporter is an exampleSimply due to concentration difference- passive transportBidirectional TransportFive types1. GLUT1Transports glucose mainly but also galactoseUsed by many cellsglycogenolysis2. GLUT2transports glucose, galactose, and fructosehigh capacity but low affinityinsulin and glucose concentration sensing mechanismsmall intestine, liver, “glucose sensor” in pancreatic beta cells3. GLUT3Transports mostly glucose but some galactoseMain transporter for neurons because have high metabolic rates and need a lot of glucose4. GLUT4Transports only glucoseInsulin responsiveThe only one that is inserted in the membranes in response to insulinglucose uptakeIn skeletal and cardiac muscle, adipocytes5. GLUT5Fructose transporterMain energy source for spermBISC 307L 1st Edition Lecture 2 Current Lecture Membrane Dynamics- Transport across membraneso 1. Directo 2. Facilitated Diffusiono 3. Osmosiso 4. Ion Channelo 5. Active transporto 6. Exo and Endocytosiso Diffusion is affected by… 1. Concentration 2. Distance 3. Temperature 4. C-S Area 5. Molecular Size 6. Lipid Solubility- Facilitated Diffusiono Glucose Transporter is an exampleo Simply due to concentration difference- passive transporto Bidirectional Transporto Five types 1. GLUT1 Transports glucose mainly but also galactose Used by many cells glycogenolysis 2. GLUT2 transports glucose, galactose, and fructose high capacity but low affinity insulin and glucose concentration sensing mechanism small intestine, liver, “glucose sensor” in pancreatic beta cells 3. GLUT3 Transports mostly glucose but some galactose Main transporter for neurons because have high metabolicrates and need a lot of glucose 4. GLUT4 Transports only glucose Insulin responsive The only one that is inserted in the membranes in response to insulinglucose uptake In skeletal and cardiac muscle, adipocytes 5. GLUT5 Fructose transporter Main energy source for
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