Membrane Plasmique Part 1 (phospho lipides et glycocalyx) Flashcards
What does it mena for something to be amphipathique? Give an example.
An amphiphile, or amphipath, is a chemical compound possessing both hydrophilic and lipophilic properties.
Phospholipids (polar head and non-bolar body)
What is the main type of glycérophospholipides?
Phospha tidyl choline
Difference between the three?
Liposome vs Micelle vs Feuillet bilamellaire
Liposome: double layered sphere
Micelle: single layered sphere
Bilamellaire: phospolipib bylayer
2 (3 for bonus) Potential movements of phospholipide
flexion
rotation
sometime flip (lower to upper)
What are the 4 possible polar heads that a glycérophospholipide can take?
PC Phosphatidylcholine
PS Phosphatidylsérine
PE Phosphatidyléthanolamine
PI Phosphatidylinositol
What are the main glycérophospholipide in the external side?
PC Phosphatidylcholine (enrichi, externe)
What are the main glycérophospholipide in the internal side?
PS Phosphatidylsérine (interne, uniquement)
PE Phosphatidyléthanolamine (interne, uniquement)
PI Phosphatidylinositol (interne, enrichi)
What is the difference between Saturated vs Unsaturated?
Unsaturated or monosaturated -> double bonds more fluid
Saturated->straight->more solid
True of Flase, A longer carbon chain is less fluid due to an increased number of bonds.
TRUE,
More carbon, more solid
What is the effect of adding Cholesterol on a phospholipid bylayer?
Cholesterol: diminue la fluidité et augmente la rigidité de la membrane
Cholesterol: amphipathique
What kind of molecule is cholesterol?
Cholesterol: amphipathique
What is Sphingolipides?
Another kind of polar head
What is the difference between Sphingolipides and glycérophospholipides?
Sphingolipides have longer chains and more straight than glycorephos.
What is a common property of both glycérophospholipides and
sphingolipides?
They can be glycolyse: adding chaine d’oses in the external membrane
What are the main Sphingolipides in the external side?
GSL = glycosphingolipides (ex, uniquement)
PC = phosphatidylcholine (enrichi)
SM = sphingomyéline (enrichi)
What are the main Sphingolipides in the internal side?
PI = phosphatidylinositol (interne,uniquement)
PE = phosphatidyléthanolamine (interne,enrichi)
PS = phosphatidylsérine (interne, uniquement)
What is radeaux lipidique?
A “radeau lipidique” (also known as a lipid raft in English) is a microdomain of the plasma membrane that is rich in cholesterol, sphingolipids
Les radeaux lipidiques sont des structures particulières de la membrane plasmique enrichies en glycosphingolipides et cholestérol, ce qui leur confère une sorte de rigidité par rapport à la membrane normale et leur permet de “flotter” dans celle-ci, d’où leur nom.
Ils sont enrichis en molécules différentes par rapport à la membrane normale, notamment des molécules de signalisation
In what part of the membrane would you excpet to see glycolipides and glycoproteines?
external feuillete
Définir le terme “glycocalyx”
protéines transmembranaires et certaines lipides sont glycosylées, de façon même intense dans certains cas, formant un glycocalyx à l’extérieure de la cellule
What is the role of a “glycocalyx”?
Important pour la protection chimique (entérocytes intestinales)
Important pour la reconnaissance cellulaire (cellules immunitaires)
Where might you find a lot of glycocalyx?
Le glycocalyx est particulièrement développé à la surface des cellules exposées à un milieu très agressif, comme dans l’intestin par exemple.
For instance, enterocytes, which are cells lining the inner surface of the intestines, have a glycocalyx surface coat that contains digestive enzymes.
