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    if the R group was hydrophillic then it would attract to water .. therefore would this be an examplke of a hydrogen bond? whne something is hydrophillic would it always be an example of a hydrogen bond?
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    no, not always. Just because something is attracted to water, doesn't mean its actually bonded to it. A hydrogen bond is only when there is an actual bond between hydrogen which is delta positive (and usually oxygen which is delta negative)
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    yh i see what u mean
    coz the O on h20 is delta negative which would attract to the R group of an amino acid? for example the R group could be simply H?
    thanks for the quick replies=]
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    Yeah, hydrophilic groups are polar, and seeing as water is also polar, they attract, via a hydrogen bond. But I'm not sure if a hydrophilic group will form hydrogen bonds with other molecules.
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    thanks 1 more thing.. could u explain what substances are able to go through the lipid bilayer and why? thanks
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    why wouldnt H be positive? because its more electonegativve isnt it?
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    as for the lipid bylayer stuff.. there are different ways molecules can cross

    things like oxygen and co2 can diffuse (move down a concentration gradient), molecules like glucose for example, need facilitated diffusion (a protein in the cell membrane facilitates the movement of glucose though the membrane by changing its shape to let it though - without this it would not enter the cell)

    water can move across by osmosis, but some things that move out of the cell are pumped, using ATP via active transport. hope this helps...
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    ye i get that stuff but i dont get why ions cant diffusee through .. they have to be faciliated.. same with amino acids and glucose.. they have to be carrierd through a carrier protein
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    (Original post by EierVonSatan)
    The difference in electronegativity is not substantial enough to make it 'polar'
    yhyh i think i get it... in OH.. H is delta negative because it is electron dificient and therefore attracts to the lone pair on the water molecule i think.. lol
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    yhyh trhats what i meant hehe.. thanks man .. also why cant amino acids cant go straight through the bilayer and have to go through via a cotransporter?
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    im pretty sure its to do with size and polarity..

    if its small and non-polar it can get though, like oxygen
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    thanks im gona give u 2 good rep=]
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    (Original post by blueberrymuffin)
    im pretty sure its to do with size and polarity..

    if its small and non-polar it can get though, like oxygen
    Yeah - Covered this a few months ago... from what i remember, charged particles cannot move through the hydrophobic centre of the bi-layer, large molecules just cant fit through.
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    yh thanks ^
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    (Original post by SS92)
    thanks im gona give u 2 good rep=]

    muchos gracias, feel free to PM me if you ever need any more help and i will do my best
 
 
 
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