Membrane Transport Flashcards
What makes up the membrane
Lipid bilayer which is amphipathic Hydrophilic phosphate head Protein fluid mosaic Many transporters Glycocalyx on top for protection
How are proteins anchored to lipid bilayer
Amino acids
What is the membrane of myocytes called
Sarcolemma
What shape are myocytes
Rectangle unusually
Many mt
What are the 2 types of transport proteins
Carriers/active transporters/pumps
(Exchangers are carriers but not active)
Channels (for ions)
How do carriers work
Have bs and change in conformation eg na / k ATPase
Explain structure of ion channels
Protein cylinders with aqueous pore in middle for ion movement
Do exchangers need atp and give example
No
Eg ca na exchanger NCX
1 ca out and 3 na in
Uses the gradient of sodium and kinetic energy pushes calcium out
How are ion channels investigated in membranes
Patch clamp technique
Glass pipette makes contact with membrane ion channels and can record current flow/electrical activity
Which protein transporters are gated
Ion channels
What 3 things can open 3 diff ion channels gates
Ligand binding (ligand gated na eg)
Voltage change
Mechanical pressure
How do you work out total current flow of ion channels
Number of ion channels x probability of channel opening x current flow of 1 ion channel
What does ion movement have to do with ecg
Ecg records electrical activity of the heart which is caused by ion movement across membrane
What does the sarcolemma have in it which allows better contact of membrane with the SR
Transverse tubules (T tubules)
What does sr do (response to ca influx into sarcolemma)
Stores and releases calcium for myocytes contraction
