8_Transport_x_membranes

8_Transport_x_membranes - 8 Transport X Membranes 3...

Info iconThis preview shows pages 1–3. Sign up to view the full content.

View Full Document Right Arrow Icon
} - } Concen potential diff across barrier - } Na/K pump 8 Transport X Membranes 3 categories 1. CELLULAR TRANSPORT Exchange of material between cell and environment (thru PM) Example: Uptake of nutrients Removal of waste Pumping of ions 2. TRANSCELLULAR TRANSPORT Moves material through the cell – in one side, out other Example: Epithelial cells of gut Plant root cells 3. INTRACELLULAR TRANSPORT Transport of material in and out of organelles MECHANISMS OF TRANSPORT: PASSIVE TRANS does NOT requires E diffusion from - conc - conc If molecule small or non-polar can pass directly thru membrane: Glycerol Ethanol Urea CO 2 O 2 H 2 O May often need specialized membrane protein to “facilitate” passage passive trans: G < O (exogonic) ACTIVE TRANPORT Requires E! G > O (endogonic) Net movement - conc - - conc Memb proteins “pumps” create conc gradients xross membranes AT REST: 2/3 of E used by body is to maintain ion gradients x membs Ex: H + , K + , Na + , Ca ++ Charged - charged gradient - elect membrane potential COMBINATION: Charge gradient Concen gradient “electrochemical gradient” Stores - Ep – used to do biological work! (syn atp)
Background image of page 1

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

View Full DocumentRight Arrow Icon
PASSIVE TRANSPORT – Diffusion occurs both directions “net” movement favored from high conc - cou G = conc P = - G = M Small molec simple diffusion Non polar molec [O 2 , [ O 2 , ET-Oh Ability governed by MEMBRANE PERMEABILITY - det by several factors - 1. Size If small enough can diffuse thru lipids – even if polar! Ex – H
Background image of page 2
Image of page 3
This is the end of the preview. Sign up to access the rest of the document.

Page1 / 6

8_Transport_x_membranes - 8 Transport X Membranes 3...

This preview shows document pages 1 - 3. Sign up to view the full document.

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