BIOL2200 Lecture Notes - Lecture 3: Oligomycin, Lactose Permease, Escherichia Coli
MEMBRANES BIOL2200 LECTRURE 3
Topic 2: transmembrane transport how things work in the cell… regulation
Permeability of phospholipid bilayer
Ethanol bc its small, water and urea can marginally get through bc they're small
Not large, ionic, charged polar
Solute transport across membranes
Essential in all organisms
oAcquire raw materials
oRelease biproducts
Membrane proteins allow this
oWithout them many important molecules couldn't enter the cell
Types of membrane transport proteins regulators
Passive transport
Simple diffusion across a permeable membrane
oTo lower energy… still movement but equally moving on each side
Electrically neutral solute
oChemical gradient
Electrically charged solute
oElectrochemical gradient (chemical and electrical gradient [Vm, membrane
potential])
Energy during membrane passage physics behind moving in a membrane
Simple diffusion
Transporter/permease: facilitated diffusion
oReduces activation energy
Remove water, push through, attract water on other side… too high a energy
requirement…. Very unlikely… so we use a transporter which makes it a nicer environment
for the ion to get through… Reducing activation energy
Classification of transporters
>1000 transporters in human genome
Carriers
oHigh specificity
oSlower
Channels
oLess specific
oFaster
Passive transport: GLUT1 allows facilitated diffusion
Glucose transporter in erythrocytes
oImplicated in diabetes
oFacilitated diffusion: 50,000x faster than uncatalysed
oPassive transport: [glucose] cannot be higher than surrounding medium
oTransport process can be described like an enzyme reaction
find more resources at oneclass.com
find more resources at oneclass.com
Document Summary
Topic 2: transmembrane transport how things work in the cell regulation. Ethanol bc its small, water and urea can marginally get through bc they"re small. Essential in all organisms: acquire raw materials o. Membrane proteins allow this: without them many important molecules couldn"t enter the cell. Simple diffusion across a permeable membrane o. To lower energy still movement but equally moving on each side. Electrochemical gradient (chemical and electrical gradient [vm, membrane potential]) Energy during membrane passage physics behind moving in a membrane. Transporter/permease: facilitated diffusion: reduces activation energy. Remove water, push through, attract water on other side too high a energy requirement . Very unlikely so we use a transporter which makes it a nicer environment for the ion to get through reducing activation energy. Glucose transporter in erythrocytes o o o o. Passive transport: [glucose] cannot be higher than surrounding medium. Transport process can be described like an enzyme reaction.
