Chapter 4 - Chapter 4 Membrane Transport I Passive Solute...

Info iconThis preview shows pages 1–4. Sign up to view the full content.

View Full Document Right Arrow Icon
1 Chapter 4 - Membrane Transport I. Passive Solute Transport a) Diffusion b) Facilitated Diffusion II. Active Solute Transport a) Primary b) Secondary III. Osmosis a) Osmolarity b) Tonicity IV. Transport Within Membrane-Bound Compartments V. Epithelial Transport VI. Resting Membrane Potential I. Passive Transport Gradients A. Chemical/Concentration Gradients –high to low (via thermal energy) B. (Ion) Electrical Gradients – from high to low (via electrical attraction) I. Passive Transport Continued • Charged substances are subject to both electrical and chemical gradients. • If these forces oppose one another, then the stronger of the two will determine the net movement - electrochemical gradient • When substances are transported down their electrochemical gradients (high to low) no energy is required (passive).
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 I.a) Simple Diffusion • Substances that move directly across the cell phospholipid bilayer, and down their chemical gradients by thermal motion (passive). • Net transfer – Nonpolar substances : steroids, fatty acids, O 2 , fat soluble vitamins. – Small polar substances : (e.g. CO 2 ) Rate of simple diffusion Depends on the following things : 1. The temperature of the solution. 2. The magnitude of the concentration difference across the membrane. 3. The size and shape of the diffusing substance 4. The permeability of the membrane to the diffusing substance. 5. The surface area of the membrane through which the substances are diffusing. 6. The thickness of the membrane. I.b) Facilitated Diffusion • The means by which large polar molecules and ionic substances are transported across the cell membrane. • Carrier Mediated Transport - Requires a (protein) carrier to cross the cell membrane • Substances still move down their electrochemical gradients (passive)
Background image of page 2
3 • Carrier-mediated transport (e.g. facilitated diffusion) depends on a protein to carry the substance across the cell membrane, therefore this type of transport involves:
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
Image of page 4
This is the end of the preview. Sign up to access the rest of the document.

{[ snackBarMessage ]}

Page1 / 8

Chapter 4 - Chapter 4 Membrane Transport I Passive Solute...

This preview shows document pages 1 - 4. Sign up to view the full document.

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