Join TSR now and get all your revision questions answeredSign up now

Phospholipid Bilayer question Watch

    • Thread Starter
    Offline

    0
    ReputationRep:
    Membranes are made up of a phospholipid bilayer. What is the use/function of:
    • cholesterol
    • glycoprotein
    • integral proteins embedded in the phospholipid bilayer


    I'm revising for an exam in 2 days so please help
    Offline

    0
    ReputationRep:
    Cholesterol molecule straightens out hydrocarbon chains. Glycoprotein- for communication and transport (i think)

    and proteins for transport- eg carrier proteins
    Offline

    1
    ReputationRep:
    Glycoproteins branch off into the surrounding fluids and stabilise the cell.
    They are also used for intracellular messaging (Antigens specifically).

    The embedded proteins could be carrier proteins / protein channels which are used in Active Transport in and out of the cell i.e. Na+ or they could be enzymes such as ATPase.

    Cholesterol maintains mechanical stability.
    Offline

    2
    ReputationRep:
    Cholesterol; to stabilise the bilayer as it would be too fluid without it.
    Glycoproteins; to act as receptors(I think)
    Integral Proteins: ion pores(to transport ions) or transport proteins(to carry glucose and amino acids)
    Offline

    0
    ReputationRep:
    Lol this thread proves how long ago it was since i did biology a-level!
    Offline

    2
    ReputationRep:
    (Original post by Hobnobs Galore)
    Lol this thread proves how long ago it was since i did biology a-level!

    Lol. count yourself lucky; it's a nightmare.
    Offline

    0
    ReputationRep:
    cholesterol stablises the membrane.
    glycoproteins are used as receptors i think.
    other proteins are used as carriers or to create channels to help transport ions/molecules across the membrane.

    hope it helps a bit!
    Offline

    2
    ReputationRep:
    (Original post by G O D I V A)
    Membranes are made up of a phospholipid bilayer. What is the use/function of:
    • cholesterol
    • glycoprotein
    • integral proteins embedded in the phospholipid bilayer


    I'm revising for an exam in 2 days so please help
    I'll help myself helping you by doing this Interview tomorrow in Cambridge - might come up:

    Cholesterol does maintain membrane fluidity - it increases fluidity at lower temperature, and vice versa at higher temperatures. The mechanism is that it acts as a wedge to seperate the phospholipid a little, thereby reducing Van Der Waals bonding and also increasing permeability to molecules.

    Glycoprotein acts as cell recognition proteins - "self and non self" really.

    Integral proteins -
    Carrier proteins - actively transport molecules across the membrane against a concentration gradient (e.g. Na - K pump).

    Protein Channels - provides a hydrophilic channel through which water solutes can diffuse through, though the protein is specific [question to others: am I right in saying this is facilitated diffusion?]

    Protein Receptors - a ligand attaches to the substrate of the protein on one end, and the other end sends a cascade signal inside the cell, expressing or inhibiting a certain gene from T&T a protein.

    Cell Adhesion - certainly some attach to the cytoskeleton inside the cell, and attach to other cell membranes.

    lol, wall of text there. Hope this helps!
 
 
 
Poll
Is GoT overrated?

The Student Room, Get Revising and Marked by Teachers are trading names of The Student Room Group Ltd.

Register Number: 04666380 (England and Wales), VAT No. 806 8067 22 Registered Office: International House, Queens Road, Brighton, BN1 3XE

Quick reply
Reputation gems: You get these gems as you gain rep from other members for making good contributions and giving helpful advice.