Membrane Plasmique Part 2

Question 1

What are the different types of proteins that you may find associated at the membrane?

Answer 1

Transmembrane

*Interseque:
Membrane associated
Tied to a lipid

*Peripherique:
Tied to another protein

Question 2

How might we get a hydrophilic pore?

Answer 2

Plusieurs hélices-𝛼 peuvent former un pore hydrophile
where the outsides are hydrophobes

Question 3

What are the 4 common transmembrane proteins?

Answer 3

Transporters
Protein d’ancrage
Receptors
Enzymes

Question 4

What are the different classes of transmembrane receptors?

Answer 4

Ionic Channels,
GPTase bound Receptors,
enzyme coupled receptors

Question 5

TRUE OR FALSE, the transmembrane phospholips can act as secondary messengers in certain conditions.

Answer 5

TRUE

IP3

Question 6

What are the molecules that can pass the membrane freely?

Answer 6

Petites molecules hydrophobes (gas,O2, CO2, N2)
petites molecules polaire (glycerol, ethanol)

Question 7

Can ions pass the membrane?

Answer 7

NO

Question 8

Can glucose pass the membrane?

Answer 8

HELL NO

Question 9

What is the difference between passive and active transport?

Answer 9

Passive: towards the [gradient], no energy
Active: Againts the [gradient], requires energy

Question 10

What are the two kinds of passive transport and what is the difference?

Answer 10

Simple Diffusion:

Assisted Diffusion:
Facilitated diffusion is saturable -> nmb of transporters vs nmb of molecules
Uses another molecure to transport the target

Question 11

~What are the two kinds of active transport?

Answer 11

Active and Vesicular

Question 12

What are the properties of active diffusion?

Answer 12

Active diffusion -> against the [] gradient,
saturable,
needs energy

Question 13

What is the difference between an ion and a glucose molecule in relation to facilitated diffusion?

Answer 13

Glucose uses the concentration gradient
And Ion will use the charge gradient mainly

For an ion the [] is less important than the membrane potential (both together)

Question 14

What are the main ions setting the membrane potential?

Answer 14

Na and K+

K+ inside Na outside

Question 15

What controls the Na K concentrations? What kind of transport is this?

Answer 15

Main Na+ K+ controller -> The NA/K pump
(for every ATP 3 sodium out and 2 Potassium in)

Active transport

Question 16

What kind of active diffusion is that of NaK transporter and why?

Answer 16

Primary as they use ATP directly

Question 17

What is an analogy to use with Na K in relation to their energy?

Answer 17

The NA outside the cell is like a dam of potential energy that really wants to flow inside the cell. This can be used to transport other molecules. This is why it is put outside

Question 18

What is coupled transportation and what are the 3 kinds?
Please provide 1 example per each kind and the properies.

Answer 18

Simply a transporter that uses two molecules to transfer them. The three kinds are:

Uniport: 1 molecule in 1 direction

Symport : 2 molecules in same direction
SGLT I; sodium-glucose transporter 1;
* Use sodium to insert glucose (see page 55)
* This is active but secondary -> doesn’t use ATP directly but the Na gradient that was created via ATP
Antiport: 2 molecules transported in different directions -> NA/K pump (primary active)

Question 19

What kind of transporter is SGLT I?

Answer 19

sodium-glucose transporter 1
symport, transport actif secondaire

Question 20

What kind of transporter is GLUT1 (-14)?

Answer 20

Passif facilitated diffusion
Passive transportation of glucose by using [glucose gradient]

Question 21

What is the difference between SGLT I and GLUT in terms of location?

Answer 21

SGLT I found apical side
GLUT found basal side

SGLT1 (Sodium-Glucose Linked Transporter 1) is found on the apical side and is responsible for the active transport of glucose across the apical membrane of enterocytes (intestinal cells). It uses the energy from sodium ion gradients to transport glucose against its concentration gradient.

On the other hand, GLUT2 (Glucose Transporter Type 2) is primarily located on the basolateral membrane of enterocytes and provides a pathway for glucose to exit the cell and enter the bloodstream.

Question 22

What makes the cytoplasme ?

Answer 22

Le contenu de la cellule (sauf le noyau)

Le cytosol + les organites