Plasma Membrane + transport etc. Flashcards
(31 cards)
Lipids found on the Outer Leaflet
1) Cholestrol
2) PhosphatidylCholine
3) Sphingomyelin
Lipids found on the Inner Leaflet?
1) Phosphatidyl…Ethanoamine/Serine/Inoistol(signal transmission).
2) Cholestrol
Which Lipids make up “Lipid Rafts”?
Cholestrol + Sphingomyelin
Types of Membrane Proteins?
1) Integral Proteins:
- Hydrophobic AA bind to Hydrophobic FA.
- Transmembrane Protein.
2) Lipid Anorched Proteins:
- Usually covalently bonded to Lipid
3) Peripheral Proteins:
- Attached to Lipid Anchor /Integral Proteins
Function of Plasma Proteins?
1) Cell to cell recognition
2) Transport
3) Enzymic Activity
4) Transport
Function of Plasma Membrane Lipids?
1) surface
2) Source of 2ndary Messengers
3) Transport of Molecules
Classification of Transport Processes
- Simple Diffusion
- Protein Mediate Transport
- Solute Carrier (Facilitated Diffusion)
- Ion Channel
- ATP Dependent (ABC and ATPase Ion Channel)
- Water channel
- Vesicular Transport
Types of Vesicular Transport?
I: Endocytosis
a) Pinocytosis: - Non specific -small molecules
b) Phagocytosis: -Large Molecule
c) Receptor-Mediated Endocytosis
II: Exocytosis:
a_ Constitutive
b_ Regulated
Types of Membrane transport
I: simple Diffusion: -occurs through membrane itself or Channel
II: Facilitated Diffusion: Occurs through Carrier Protein
III: Active Transport: Via Carriers
Difference Between Carriers and Channels?
Carrier:
- specific
- slow (cycles)
- saturation
- Active/Passive
Channels:
- fast
- passive
- no saturation
Explain Simple Diffusion
- Passive Process
- Uses Channels/Membrane
- Fick’s First Law
- Dm proportional to Hydrophobicity and size
Characteristics of “Facilitated Diffusion”
1) Passive
2) Not linked to Metabolic Energy
3) Is Protein-Mediated Transport (faster than simple diffusion)
4) Specific
5) Saturation can occur
Difference Between Uniporters for glucose?
- Uniporters have different Transport Kinetics
- Glu1 (erthocytes) faster than Glu2 (B-Cells).
Characteristics of “Glucose Transporter”
- Uniporters
- ECF->ICF
- Glu1 (RBC), Glu2 (b-cells), Glu4 = insulin dependent.
- passive
- electroneutrel
Characteristics of “HCO3-,Cl- Transporter”
- Co-transport/Antiporters
- Electroneutral
- Passive
Characteristics of “Na+,K+ ATPase”
I) 3Na+ -> ECF II) 2K+ -> ICF III) electrogenic IV) Active V) Inhibited by Qubain
Characteristics of “Ca2+, ATPase”
- uniporter
- Active
ABC transporter Characteristics
- ATP binding Casette
- Active transport of Hydrophobic moelcules.
- Involved in drug removal
Water Transport through the membrane
-Lipid Bilayer has Low Permeability to water.
Transport can occur via:
I: Passive Transport (driven by Osmotic Pressure)
II: Protein Mediated Transport (AQPs regulated by # and pH)
what is osmotic pressure and how do we calculate it
Osmotic Pressure is the pressure required to stop osmosis.
Van’t Hoff’s Law:
pi = nCRT n= number of associable molecules
What is the Reflection Co-effecient
Delta, another parameter added to the Van’t Hoff’s Law:
Delta = 0 -Can pass through the membrane thus has no osmotic pressure generation - ineffective osmole
Effective Osmole:
delta= 1
cannot pass though the membrane so creates osmotic pressure (ie//sucrose)
What is “Tonicity”?
Tonicity is the effect of a solution on the volume of a soln.
Isotonic - same size (Na, Sucrose)
hypotonic - increase in size (Urea
hypertonic - decrease in size
What is “Oncotic Pressure”
This is used for Osmotic pressure for Large Molecules (like proteins).
Osmotic pressure undercalculates the actual pressure generated.
Characteristics: Nucleus
- Contains Genome
- 22 Autosomal pairs, 1 sex pair
- Contains enzyme machinary for replication, transcription, repair
