somasimple

The electrochemical gradient can't work because the ions in the channel creates an electrostatic/electric force that is ever superior to an hypothetic electrochemical gradient.

Accordingly to the second link I provided and the actual cited gradients, the concentration is ever higher in the pore/channel than elsewhere then the gradient is lower (before sieving) and lower at destination. It does not work! Otherwise and also in facilitated transport, you're facing the same situation... :naughty:

Sorry but we are not speaking about NaK pump. I'm speaking about a simple K channel.

Hi All, A potassium channel is designed to filter out potassium ions at a maximum rate of 100,000,000 ions s-1 A common concentration (cell's interior) of potassium is 100 mM and 5 mM outside. This means there is 553 water molecules for 1 potassium ion inside (55.3/0.100) and 11,060 water molecules for a ion outside (55.3/0.005). Ionic concentration / number of ions If the channel acts as a sieve then what happen to the local concentrations, inside and outside? ref: rate => http://www.pdb.org/pdb/static.do?p=education_discussion/molecule_of_the_month/pdb38_1.html water => http://www.pdb.org/pdb/static.do?p=education_discussion/molecule_of_the_month/pdb38_4.html ps: local concentration (concentration that exists just around the channel ~ few nm)

Trolling? Is it the only response you're able to give when you encounter some contradiction? :) Ion hydration and aqueous solutions of salts

Right! Do you know pure water, yes? BTW,your point of view is water is neutral => It can't store charge.... Hmm, I have another example: Nitrogen (N2) is neutral, so is oxygen (O2) and you insist in the fact that water is neutral, too. Well, how is a cloud (made from these neutral molecules), able to store the little charges we call thunder and lightning? ;) I think that you do not have a clue about what a cluster is! :)

Bogus and cited in PubMed... Langmuir. 2007 Nov 6;23(23):11890-5. Epub 2007 Oct 16. Visualization of charge-carrier propagation in water. Klimov A, Pollack GH. Department of Bioengineering, Box 355061, University of Washington, Seattle, Washington 98195, USA. The electrical properties of water in the region between parallel electrodes were investigated using pH indicator dyes. Different pH values corresponded to different colors, which could be registered by a video camera. Imposition of electrical current was able to produce zones of constant pH around, and well beyond each electrode: extremely low pH around the positive electrode and extremely high pH around the negative electrode. The border between alkaline and acid zones was jagged and separated by only a narrow layer of water with neutral pH. When the water was replaced by various salt solutions, similar zones were observed. Again, passage of current produced large zones of extreme pH values near and beyond each electrode. Alkaline zones appeared to propagate from the negative to the positive electrode in narrow channels through the neutral solution. When the power supply was disconnected from the electrodes and replaced by a resistive load, a potential difference was registered, and current flowed through the resistor for some period of time. Hence, the acid and alkaline zones appear to carry opposite charges throughout their volume. PMID: 17939693 [PubMed - indexed for MEDLINE] Ion hydration and aqueous solutions of salts

A molecule may be neutral taken as a whole and have local charges because is it a polar molecule. BTW, ionization occurs in water. Water ionization,the ionic product (Kw) of water and pH

What happens when we have a positive charge? ;) How are you able to cite a PH without knowing that it is about the H+ charge contained in a solution? :) pH - Wikipedia, the free encyclopedia

The approximate shape and charge distribution of water What is a charge?

It is not what chemists say: Water molecule structure

I was told that MRI units works because it change the orientation of water molecules : Diffusion MRI - Wikipedia, the free encyclopedia here is a page about ion hydration: How is it possible to a ion to attract water molecules if they are non ionic? Ion hydration and aqueous solutions of salts

Yes, Salt is Na+ and Cl-: Clearly they are ions. Seriously, water preserves electroneutrality because it dampens all ions (electrostatic forces) in it. Water make a shield around ions that diminishes its strength but water gets at the same time a little force from the enclosed ions. The H bonds are simply enlarged or reduced in distance...

The better way to ionize water is to add salt... :)

Here is is a ink to the free full text: Enjoy; BTW, it makes sense since water is a polar molecule. ACS Publications - Cookie absent