Ch5-The Dynamic Cell Membrane

Ch5-The Dynamic Cell Membrane - 5 The Dynamic Cell Membrane...

Info iconThis preview shows pages 1–11. Sign up to view the full content.

View Full Document Right Arrow Icon
5 The Dynamic Cell Membrane
Background image of page 1

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

View Full DocumentRight Arrow Icon
5 The Dynamic Cell Membrane 5.1 What Is the Structure of a Biological Membrane? 5.2 How Is the Plasma Membrane Involved in Cell Adhesion and Recognition? 5.3 What Are the Passive Processes of Membrane Transport? 5.4 How Do Substances Cross Membranes Against a Concentration Gradient? 5.5 How Do Large Molecules Enter and Leave a Cell? 5.6 What Are Some Other Functions of Membranes?
Background image of page 2
5.1 What Is the Structure of a Biological Membrane? The general structure of membranes is known as the fluid mosaic model . The phospholipid bilayer is like a “lake” in which a variety of proteins “float.”
Background image of page 3

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

View Full DocumentRight Arrow Icon
Figure 3.20 Phospholipids (A) Repeat Fig 3.20A here Figure 5.2 A Phospholipid Bilayer Separates Two Aqueous Regions
Background image of page 4
5.1 What Is the Structure of a Biological Membrane? Lipids maintain a bilayer organization spontaneously membranes fuse during phagocytosis vesicle formation, etc. Membranes may vary in lipid composition Phospholipids vary—fatty acid chain length, degree of saturation, phosphate groups Membranes may be up to 25 percent cholesterol Phospholipid bilayer is flexible, and the interior is fluid, allowing lateral movement of molecules. Fluidity depends on temperature and lipid composition
Background image of page 5

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

View Full DocumentRight Arrow Icon
Membranes contain proteins, the number of proteins varies with cell function Some membrane proteins extend across the lipid bilayer—with hydrophobic and hydrophilic regions or domains . The proteins and lipids in the membrane are independent and only interact noncovalently. Figure 5.3 Membrane Proteins Revealed by the Freeze-Fracture Technique
Background image of page 6
Two types of membrane proteins: Integral membrane proteins span the bilayer hydrophilic ends protrude on either side. Peripheral membrane proteins do not penetrate the bilayer. Figure 5.4 Interactions of Integral Membrane Proteins
Background image of page 7

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

View Full DocumentRight Arrow Icon
5.1 What Is the Structure of a Biological Membrane? Transmembrane proteins may have different domains on either side of the membrane. The two sides of the membrane can have very different properties. Some membrane proteins can move freely within the bilayer, while some are anchored to a specific region. Some can be anchored by cytoskeleton elements, or lipid rafts —lipids in semisolid state.
Background image of page 8
Membranes are dynamic and are constantly forming, transforming, fusing, and breaking down. Figure 5.5 Dynamic Continuity of Membranes
Background image of page 9

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

View Full DocumentRight Arrow Icon
5.1 What Is the Structure of a Biological Membrane? Membranes have carbohydrates on the
Background image of page 10
Image of page 11
This is the end of the preview. Sign up to access the rest of the document.

This note was uploaded on 04/09/2008 for the course BIO 140 taught by Professor Morvaridsoltani-bejnood during the Spring '08 term at University of Tennessee.

Page1 / 35

Ch5-The Dynamic Cell Membrane - 5 The Dynamic Cell Membrane...

This preview shows document pages 1 - 11. Sign up to view the full document.

View Full Document Right Arrow Icon
Ask a homework question - tutors are online