MembraneTransport_review

MembraneTransport_review - BICD 110 SSII 09 Membrane...

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

View Full Document Right Arrow Icon
BICD 110 SSII 09 Membrane Transport I. Transport Across Membranes: A. Why do entities need to travel across the Membrane? 1. Means of Ingesting Essential Nutrients 2. Excrete Waste Products 3. Regulate Intracellular [Ion/ Solute] Etc. B. Factors that influence Permeability of the Bilayer 1. Size 2. Solubility in Hydrophobic Environment 3. Permeability Coefficient - Units: cm/ sec D. Permeability of the Bilayer a) Nonpolar Molecules (O 2 , hydrocarbons, fatty acids) Bilayers are most permeable to small nonpolar molecules b) Small Uncharged Polar Molecules (H 2 O, CO 2 ) Bilayers are somewhat permeable to small uncharged polar molecules c) Large Polar molecules and Ions Bilayers are relatively impermeable to large polar molecules and to ions d) Macromolecules (proteins, nucleic acids, polysaccharides) Cannot pass unless a special mechanism exists E. Means of Overcoming Obstacles of Permeability: - Membrane Transport Proteins: 1. Carrier Proteins (Transporters/ Permeases) 2. Channels
Background image of page 1

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

View Full DocumentRight Arrow Icon
- Types of Transport Mode of Transport Substrate Gradient Energy Required Saturation? Need MB Protein Simple Diffusion Small, hydrophobic, uncharged Chemical/ Concentration Gradient NO NO NO Passive Transport - Lots of small molecules, both charged and uncharged - Ions Chemical/ Concentration OR Electrochemical Gradient NO YES YES - Carriers - Channels Active Transport - small molecules, charged and uncharged, proteins, lipids, etc. - lots of things Chemical/ Concentration OR Electrochemical Gradient YES YES YES - Carriers - Diagram
Background image of page 2
II. Active Transport - Forms of Active Transport 1. Coupled Carrier - Uphill transport of one solute is coupled to the downhill transport of another solute - Two types of coupled carriers - Symporters - Antiporters 2. ATP Driven Pump - Hydrolysis of ATP 3. Light - Bacteria III. Primary (1 ° ) Vs. Secondary (2 ° ) Active Transport A . Primary Active Transport: 1. Directly uses Energy to transport molecules across a membrane - Proteins that utilize 1 ° Active Transport are generally Transmembrane ATPases - An ATPase procures Energy from the Hydrolysis of ATP - Ex: Sodium- Potassium Pump (Na+/ K+ ATPase) B. Secondary Active Transport: 1. NO direct coupling of ATP Hydrolysis 2. Free Energy that is released during the movement of a solute down its gradient is used as the driving force to pump other solutes up their gradient - Ex: Glucose/ Na+ Symport Fig. 11-35 Lehn IV. Na+/ K+ ATPase: (Ex: Primary Active Transport)
Background image of page 3

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

View Full DocumentRight Arrow Icon
A. General Characteristics: 1. A P-type ATPases - ATP-driven cation transporters that are reversibly phosphorylated by ATP as part of transport mechanism 2. Ion Transport against an Electrochemical Gradient 3 Na + pumped out against an Electrochemical Gradient 2 K + pumped in against an Electrochemical Gradient - Mnemonic: Pumpkin = Pump- K- In 3. Functions of the Na+/ K+ ATPase a. Regulates Cell Volume b. Establishes and Controls Membrane Potential
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.

Page1 / 11

MembraneTransport_review - BICD 110 SSII 09 Membrane...

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