Lec8Translocationnotes

Osmosis diffusion from high eg solute golow partial

Info iconThis preview shows page 1. Sign up to view the full content.

View Full Document Right Arrow Icon
This is the end of the preview. Sign up to access the rest of the document.

Unformatted text preview: along a gradient in total pressure mass flow involves the total psushing of both of the molecule so in this case the sucrose and the water. Osmosis Diffusion from high (e.g. solute) golow partial pressure(e.g. water) to high conc so they diffuse low partial pressure http://en.wikipedia.org/wiki/File:Dif fusion.svg less water more water water wlll move into where there is more solute, which is the left side * MASS FLOW semi permeable membrane * http://en.wikipedia.org/wiki/Osmosis so when first example when you are blowing air out of your mouth, there is high pressure inside ur mouth and low outside. Mechanism of Phloem Translocation Phloem is driven by pressure gradient. • Munch Pressure-Flow Hypothesis so water diffuse out of this tube into the other compartment and this will happen until equilibrium – Translocation in phloem is driven by a pressure gradient from source to sink – Phloem loading at source and phloem unloading at sink two container connected and they both have water, and there is more concentration on the right side. Translocation low h20 conc Mechanism of Phloem Translocation we need to have a difference in the amount of solute between the two compartment • Requirements – Osmotic gradient between two osmometers – Membranes that allow establishment of gradient – A low-resistance pathway (tube) between osmometers that allows flow Translocation Mechanism of Phloem Translocation • So: – Loading of sugar into the phloem results in dilution of water – Osmosis generates the influx of water into the phloem at the loading site = a pressure – The pressure difference then results in mass flow, moving solute and solvent along the phloem to a lower pressure – Unloading of sugar at the sink results in less dilution...
View Full Document

This document was uploaded on 01/17/2014.

Ask a homework question - tutors are online