Lecture 1 Holmes Flashcards
Rate of Diffusion
J = PA(dC)
Where
- J= net rate of diffusion (mmol/sec)
- P=permeability
- A= surface area
- dC = different in concentration, aka concentration gradient (clinically relevant)
Where P = SOL/T*(MW)^.5
- SOL = solubility of substance, sometimes varies with acidosis or certain drugs
- T= membrane thickness, very clinically relevant
- MW = molecular weight
Why is the membrane an insulator?
ions and other charged molecules do not dissolve in the hydrophobic lipid core of the bilayer. Therefore, the membrane functions as an energy barrier for a charged ion to pass through
3 ways molecules are transported into cells
- passive diffusion
- passive transport
- active transport
Primary active transport
- against electrochemical gradient
- protein and energy dependent
Secondary active transport
Against electrochemical gradient driven by ion movement down its gradient
Passive transport
- down electrochemical gradient
- OR carrier-mediated
- protein dependent
Which pKa values will lead to the greatest variation in membrane partitioning in vivo?
A) 3.5
B) 7.5
C) 10.5
Which pKa values will lead to the greatest variation in membrane partitioning in vivo?
A) 3.5
B) 7.5
C) 10.5
Phospholipids
lipid + protein
have strutural AND signaling roles in membrane
Michaela’s metakinetics
Cholesterol
Lipid based on steroid nucleus (4 hydrocarbon rings)
Phosphatidylserine
Sphingomyelin
Phosphatidylcholine
Types of phospholipids
glycerophospholipids (Glycerol-alcohol based phospholipids)
Phosphoinositides: (inositol-alcohol based phospholipids)
Phosphosphingolipids (sphingol-alcohol based phospholipids)
Types of glycerophospholipids
- Plasmalogens
- Phosphatidates
- Phosphatidylcholines
- glycolipids
Membrane protein functional classes
- Cell adhesion proteins
- Receptors
- Transporters
- Ion channels
Functions of the plasma membrane
- physical barriers, allows for build up of gradients
- Communication interface, supports signal transduction (chemical and electrical)
Hyper(hypo)kalemia
high (low) level of potassium
Hyper(hypo)natremia
high(low) levels of sodium
Alkalemia
high pH, caused by alkalosis
Acidemia
low pH caused by acidosis
