{[ promptMessage ]}

Bookmark it

{[ promptMessage ]}

Lecture 8 Pumps and Channels - Biochemistry415/515...

Info icon This preview shows pages 1–12. Sign up to view the full content.

View Full Document Right Arrow Icon
1 Biochemistry, Seventh Edition Chapter 12 and 13 Biochemistry 415/515 Section 1 & 2 Mark A Saper  Lecture 21 Membranes Channels and Pumps Figures in this presentation, unless otherwise noted, are ©2011, 2007, 2002 by W. H. Freeman & Co.
Image of page 1

Info icon This preview has intentionally blurred sections. Sign up to view the full version.

View Full Document Right Arrow Icon
2 Section 2 Monday’s class (10/31/2011) is in North Lecture Hall Exam next Wednesday on lectures through today Section 1 Exam Locations: 1324 & 1360 & 1084 East Hall Section 2 Exam Locations: 1210 & 1640 CHEM, 6311 MS I
Image of page 2
3 From membrane lipids to lipid membranes: Eukaryotic cells contain multiple compartments bounded by membranes • Phospholipids, glycolipids, and cholesterol form the basic structure of membranes. • Proteins carry out most membrane functions.
Image of page 3

Info icon This preview has intentionally blurred sections. Sign up to view the full version.

View Full Document Right Arrow Icon
4 Membrane lipids are amphipathic molecules: contain both a hydrophobic and hydrophilic moiety A common structural theme Cholesterol Hydrocarbon tails interact with one another in preference to water Polar head group favors contact with water
Image of page 4
5 Section of a fatty acid micelle Polar heads face the water Hydrophobic tails associate. Hydrophobic interactions drive the self-assembly of micelles and bilayers
Image of page 5

Info icon This preview has intentionally blurred sections. Sign up to view the full version.

View Full Document Right Arrow Icon
6 Lipid bilayers form spontaneously by a self assembly process Hydrophobic interactions are the driving force for lipid bilayer formation Phospholipids and glycolipids form bilayers
Image of page 6
7 Membranes are three-dimensional solutions of oriented lipids and globular proteins Functions of the bilayer: 1) as a solvent for integral membrane proteins 2) as a permeability barrier Fluid mosaic model
Image of page 7

Info icon This preview has intentionally blurred sections. Sign up to view the full version.

View Full Document Right Arrow Icon
8 Fluid mosaic model membrane asymmetry Proteins and lipids diffuse laterally
Image of page 8
9 Biological membranes are structurally and functionally asymmetric Outer and inner surfaces of membranes have different components and enzymatic activities Lipids are asymmetrically distributed: Outer leaflet: sphingomyelin, PC Inner leaflet: PE, PS Proteins are asymmetrically oriented with functional consequences (receptors for growth factors, Na + -K + pump)
Image of page 9

Info icon This preview has intentionally blurred sections. Sign up to view the full version.

View Full Document Right Arrow Icon
10 Length affects Tm: Long hydrocarbon chains interact more strongly than short (Tm increases with increasing chain length) Double bonds affect Tm: A cis double bond introduces a bend which interferes with packing of the hydrocarbon chains, lowering Tm Membrane fluidity is controlled by fatty acid composition and cholesterol content
Image of page 10
11 In animals , cholesterol is a key regulator of membrane fluidity How do bacteria regulate membrane fluidity? At high temperatures, cholesterol reduces membrane fluidity (interacts with the hydrocarbon tails of the PLs) At low temperatures, cholesterol maintains membrane fluidity (rings prevent gelling).
Image of page 11

Info icon This preview has intentionally blurred sections. Sign up to view the full version.

View Full Document Right Arrow Icon
Image of page 12
This is the end of the preview. Sign up to access the rest of the document.

{[ snackBarMessage ]}

What students are saying

  • Left Quote Icon

    As a current student on this bumpy collegiate pathway, I stumbled upon Course Hero, where I can find study resources for nearly all my courses, get online help from tutors 24/7, and even share my old projects, papers, and lecture notes with other students.

    Student Picture

    Kiran Temple University Fox School of Business ‘17, Course Hero Intern

  • Left Quote Icon

    I cannot even describe how much Course Hero helped me this summer. It’s truly become something I can always rely on and help me. In the end, I was not only able to survive summer classes, but I was able to thrive thanks to Course Hero.

    Student Picture

    Dana University of Pennsylvania ‘17, Course Hero Intern

  • Left Quote Icon

    The ability to access any university’s resources through Course Hero proved invaluable in my case. I was behind on Tulane coursework and actually used UCLA’s materials to help me move forward and get everything together on time.

    Student Picture

    Jill Tulane University ‘16, Course Hero Intern