Membrane Plasmique Part 1 (phospho lipides et glycocalyx)

Question 1

What does it mena for something to be amphipathique? Give an example.

Answer 1

An amphiphile, or amphipath, is a chemical compound possessing both hydrophilic and lipophilic properties.

Phospholipids (polar head and non-bolar body)

Question 2

What is the main type of glycérophospholipides?

Answer 2

Phospha tidyl choline

Question 3

Difference between the three?
Liposome vs Micelle vs Feuillet bilamellaire

Answer 3

Liposome: double layered sphere
Micelle: single layered sphere
Bilamellaire: phospolipib bylayer

Question 4

2 (3 for bonus) Potential movements of phospholipide

Answer 4

flexion
rotation

sometime flip (lower to upper)

Question 5

What are the 4 possible polar heads that a glycérophospholipide can take?

Answer 5

PC Phosphatidylcholine
PS Phosphatidylsérine
PE Phosphatidyléthanolamine
PI Phosphatidylinositol

Question 6

What are the main glycérophospholipide in the external side?

Answer 6

PC Phosphatidylcholine (enrichi, externe)

Question 7

What are the main glycérophospholipide in the internal side?

Answer 7

PS Phosphatidylsérine (interne, uniquement)
PE Phosphatidyléthanolamine (interne, uniquement)
PI Phosphatidylinositol (interne, enrichi)

Question 8

What is the difference between Saturated vs Unsaturated?

Answer 8

Unsaturated or monosaturated -> double bonds more fluid
Saturated->straight->more solid

Question 9

True of Flase, A longer carbon chain is less fluid due to an increased number of bonds.

Answer 9

TRUE,

More carbon, more solid

Question 10

What is the effect of adding Cholesterol on a phospholipid bylayer?

Answer 10

Cholesterol: diminue la fluidité et augmente la rigidité de la membrane
Cholesterol: amphipathique

Question 11

What kind of molecule is cholesterol?

Answer 11

Cholesterol: amphipathique

Question 12

What is Sphingolipides?

Answer 12

Another kind of polar head

Question 13

What is the difference between Sphingolipides and glycérophospholipides?

Answer 13

Sphingolipides have longer chains and more straight than glycorephos.

Question 14

What is a common property of both glycérophospholipides and
sphingolipides?

Answer 14

They can be glycolyse: adding chaine d’oses in the external membrane

Question 15

What are the main Sphingolipides in the external side?

Answer 15

GSL = glycosphingolipides (ex, uniquement)
PC = phosphatidylcholine (enrichi)
SM = sphingomyéline (enrichi)

Question 16

What are the main Sphingolipides in the internal side?

Answer 16

PI = phosphatidylinositol (interne,uniquement)
PE = phosphatidyléthanolamine (interne,enrichi)
PS = phosphatidylsérine (interne, uniquement)

Question 17

What is radeaux lipidique?

Answer 17

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

Question 18

In what part of the membrane would you excpet to see glycolipides and glycoproteines?

Answer 18

external feuillete

Question 19

Définir le terme “glycocalyx”

Answer 19

protéines transmembranaires et certaines lipides sont glycosylées, de façon même intense dans certains cas, formant un glycocalyx à l’extérieure de la cellule

Question 20

What is the role of a “glycocalyx”?

Answer 20

Important pour la protection chimique (entérocytes intestinales)
Important pour la reconnaissance cellulaire (cellules immunitaires)

Question 21

Where might you find a lot of glycocalyx?

Answer 21

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.