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  1. 04 Nov '10 03:49
    ...anything about passive transport via protein pathway through phospholipid layers in eukaryotic cells?

    Google Scholar is failing me tonight!

  2. Subscriber AThousandYoung
    Do ya think?
    04 Nov '10 04:44
    Originally posted by mlprior
    ...anything about passive transport via protein pathway through phospholipid layers in eukaryotic cells?

    Google Scholar is failing me tonight!

    Sure.

    Eukaryotic cells are the more "advanced" type of cell which has various specialty compartments called organelles. These is what animals and plants are made of. Bacteria, on the other hand, are prokaryotes. They have no nucleus and their DNA just kinda floats semi freely. Eukaryotes have the DNA packaged up in a nucleus.

    The "skin" of a cell is made of phospholipid molecules arranged in a bilayer formation, with the polar "heads" facing inside and outside the cel, and the nonpolar "tails" are inside the "skin" itself. Try searching for "micelle".

    Now, humans have holes in our bodies which are intended to allow substances in and out of our bodies. The mouth takes in food, the nostrils take in and exhale air and CO2, etc. If you want to put something inside a person without using these holes you need to punch a hole in the skin with a needle or something. However you can put things "inside" the person by having them swallow it, or breathe it, or stick it up their butt, or whatever.

    Cells have similar holes in their membranes, and those holes are held open by proteins. Those proteins can function in active or passive ways. Active proteins are like your mouth and throat; they actively move substances from one side to the other. Passive proteins are more like your ears; things can go inside, but there is no mechanism in the ear pushing things out or pulling them in.

    So, in short, you are asking about holes in plant/animal type cells' skins made of proteins but which are unpowered portals for whatever to pass in or out of the cell via diffusion.
  3. 04 Nov '10 05:06
    Originally posted by AThousandYoung
    Sure.

    Eukaryotic cells are the more "advanced" type of cell which has various specialty compartments called organelles. These is what animals and plants are made of. Bacteria, on the other hand, are prokaryotes. They have no nucleus and their DNA just kinda floats semi freely. Eukaryotes have the DNA packaged up in a nucleus.

    The "skin" of a ...[text shortened]... h are unpowered portals for whatever to pass in or out of the cell via diffusion.
    Wow, you are just a regular Wikepedia, eh?

    Great information, really!

    What I am trying to figure out, I need to come up with a way to allow the passage of lipids through a polymer matrix that I am creating, or at least make it easier for the passage of lipids. The lipids are being created on one side and the solvent (hexane) will be on the other side of the polymer.
    The matrix is made through polymerization of smaller polymer units and I can put anything into the mix that I want before I solidify it. I was thinking of copying what the actual cell does in using protein pathways. So, I could maybe mix a similar protein into the polymer and that would be incorporated into the matrix.
    It would have to be passive since there is no phospholipid layer.....unless I used phospholipids to make the polymer.....hmmmmm
  4. Subscriber AThousandYoung
    Do ya think?
    04 Nov '10 06:10 / 1 edit
    Originally posted by mlprior
    Wow, you are just a regular Wikepedia, eh?

    Great information, really!

    What I am trying to figure out, I need to come up with a way to allow the passage of lipids through a polymer matrix that I am creating, or at least make it easier for the passage of lipids. The lipids are being created on one side and the solvent (hexane) will be on the ot ...[text shortened]... ce there is no phospholipid layer.....unless I used phospholipids to make the polymer.....hmmmmm
    Wow. You sound like an actual lab chemist. I thought you were a layperson.

    What is the polymer's structure? What's the monomer? I'm guessing the polymer is a two dimensional sheet sort of thing like a cell membrane, right? By the way, cell membranes are NOT polymers.

    There need to be holes in the polymer that the lipids can physically fit through, so you need to know how big the lipid molecules in question are and the structure of the polymer.

    What lipids are being created?

    EDIT - Solvents aren't one "the other side" - solvents are on both sides. What solvent are the lipid molecules being created in? What's creating them?
  5. 04 Nov '10 14:53 / 1 edit
    Originally posted by AThousandYoung
    Wow. You sound like an actual lab chemist. I thought you were a layperson.

    What is the polymer's structure? What's the monomer? I'm guessing the polymer is a two dimensional sheet sort of thing like a cell membrane, right? By the way, cell membranes are NOT polymers.

    There need to be holes in the polymer that the lipids can physically fit thr both sides. What solvent are the lipid molecules being created in? What's creating them?
    Layperson? Pfffttt!

    The initial polymer is Alginic Acid, sodium salt (1 solution in H2O. I add the cells (algae) into the 1% solution and drop it into calcium chloride. The divanent calcium replaces the monovalent sodium, causing the alginic acid to fold over onto itself, polymerizing. It basically makes little encapsules of algae, about 2 to 4 mm diameter. The alginate is semi-permeable, enough to show a good growth when encapsulated. The algae makes lipids (triterpenes) that I need to get out, through they are high molecular weight lipids, 466 MW, so much larger than the nutrients that are permeating through. The specific lipid name is "botryococcene".

    On contact with hexane, some of the lipids do come through, but only about 20% of possible extracellular lipids. So, that is the problem.


    edit: that smily face is supposed to be a percent sign.
  6. Subscriber AThousandYoung
    Do ya think?
    05 Nov '10 08:34 / 3 edits
    OK. You're encapsulating algae cells in this stuff. Well, you would need a cylindrical protein with a very nonpolar inner surface and an outer surface that is attracted to the alginate so it would embed itself properly and the lipids would not be repelled by the inner surface.

    I think you're looking for a "transmembrane lipoprotein" of some sort. Also investigate"porin", "uniporter" and "facilitated diffusion".