Class notes
Module 3 Notes 2023-24
- Course
- PHGY 170
- Institution
- Queen’s University (QU )
Enriched module 3 notes.
[Show more]
Seller
Follow
Content preview
Section 1: Introduction to the plasma membrane and lipidsFluid mosaic - membranes are fluid, individual components can move around
They are semi-permeable (only certain materials may freely cross – large and charged
substances are typically blocked)
They are selective (membrane proteins may regulate the passage of material that cannot freely
cross)
Structure of Phospholipids:
➔ Consist of a polar head (hydrophilic)
◆ glycerol
● three carbon chain with hydroxyl
group
○ acts as the backbone of the
phospholipid
◆ phosphate
● hydrophilic charged phosphate group molecule
➔ Consist of two non-polar tails (hydrophobic) composed of fatty acid (hydrocarbon)
chains.
◆ Vary in composition which can alter rigidity
➔ Because phospholipids contain both hydrophilic (water-loving) and lipophilic (fat-loving)
regions, they are classed as amphipathic.
, Polar Phospholipid Head groups:
PI=cytosolic leaflet
Charged Phospholipid Head Groups:
, PS= negatively & cytosolic leaflet, PE= positive & cytosolic leaflet, PC= positive &
exoplasmic leaflet
Cholesterol:
➔ Hydrophobic
➔ Has a hydroxyl group on one of its rings
◆ This ring will interact with the surface of the membrane
◆ The rest of the rings will interact with the lipid part of the membrane
Interacts with the fatty acid tails of phospholipids to moderate the properties of the
membrane:
➔ Cholesterol functions to immobilize the outer surface of the membrane, reducing fluidity
➔ It makes the membrane less permeable to very small water-soluble molecules that would
otherwise freely cross
➔ It functions to separate phospholipid tails and so
prevent crystallization of the membrane
The benefits of buying summaries with Stuvia:
Guaranteed quality through customer reviews
Stuvia customers have reviewed more than 700,000 summaries. This how you know that you are buying the best documents.
Quick and easy check-out
You can quickly pay through credit card or Stuvia-credit for the summaries. There is no membership needed.
Focus on what matters
Your fellow students write the study notes themselves, which is why the documents are always reliable and up-to-date. This ensures you quickly get to the core!
Frequently asked questions
What do I get when I buy this document?
You get a PDF, available immediately after your purchase. The purchased document is accessible anytime, anywhere and indefinitely through your profile.
Satisfaction guarantee: how does it work?
Our satisfaction guarantee ensures that you always find a study document that suits you well. You fill out a form, and our customer service team takes care of the rest.
Who am I buying these notes from?
Stuvia is a marketplace, so you are not buying this document from us, but from seller cassandranono. Stuvia facilitates payment to the seller.
Will I be stuck with a subscription?
No, you only buy these notes for CA$12.92. You're not tied to anything after your purchase.
Can Stuvia be trusted?
4.6 stars on Google & Trustpilot (+1000 reviews)
84866 documents were sold in the last 30 days
Founded in 2010, the go-to place to buy study notes for 14 years now