Wi10-Lec5 - Lecture 5 Membranes and Enzymes Announcements...

Info iconThis preview shows pages 1–5. Sign up to view the full content.

View Full Document Right Arrow Icon
1 Lecture 5 Membranes and Enzymes Announcements • Printed 10 chapters of What is Life • Homework #2
Background image of page 1

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

View Full Document Right Arrow Icon
2 The Plasma membrane is a “fluid mosaic” A Phospholipid Bilayer with embedded proteins extracellular fluid (outside) carbohydrate phospholipid cholesterol binding site phospholipid bilayer recognition protein receptor protein transport protein protein filaments cytoplasm (inside) Membrane proteins: The “tiles” of the Mosaic – Transport proteins: allow things to get across – Receptor proteins: binding sites on the outer membrane for chemicals and hormones – Recognition proteins: used by the immune system to identify cells as belonging to “self”
Background image of page 2
3 Membrane Structure • The phospholipid bilayer is the fluid portion of the membrane. • Phospholipid molecules have a polar head group and a pair of nonpolar tails. Fig. 3-2 head (hydrophilic) tails (hydrophobic) H 2 CO O CCH 2 CH 2 CH 2 CH 2 CH 2 CH 2 CH 2 CH 2 CH 2 CH 2 CH 2 CH 2 CH 2 CH 2 CH 2 CH 2 CH 3 CH 2 CH 2 CH 2 CH 2 CH 2 CH 2 CH 2 CH 3 CH CH 2 CH 2 CH 2 CH 2 CH 2 CH 2 CH 2 CH HC O C O H 3 CNCH 2 CH 2 OPOCH 2 CH 3 CH 3 + O O Membrane Structure • Head groups are hydrophilic and point toward the aqueous environment (water) on both sides of the membranes. • Tail groups are hydrophobic and point away from the aqueous environments and toward each other. Fig. 3-3 phospholipid hydrophilic heads hydrophobic tails hydrophilic heads bilayer extracellular fluid ( watery environment ) cytoplasm ( watery environment )
Background image of page 3

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

View Full Document Right Arrow Icon
The Plasma Membrane: A Gatekeeper The phospholipid bilayer blocks the passage of most large and most polar molecules. How does it do that?
Background image of page 4
Image of page 5
This is the end of the preview. Sign up to access the rest of the document.

{[ snackBarMessage ]}

Page1 / 23

Wi10-Lec5 - Lecture 5 Membranes and Enzymes Announcements...

This preview shows document pages 1 - 5. Sign up to view the full document.

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