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  1. M

    A level Biology: Post your doubts here!

    so there are 3 types of natural selction \ 1-directional selection : in which an environmental change causes a change in the gene pool of a population favoring one characterstict over the others e e.g. the peppered mot example 2-stablising selection : in which the environmental factor is...
  2. M

    A level Biology: Post your doubts here!

    dude section b before it included the core syllabus only but this year application syllabus will be included in section b... :( check out the syllabus !
  3. M

    Nationality :D

    im from iraq.. living in UAE
  4. M

    Chem P42

    no i guess the lowest gt was for the last year or p43 and p41
  5. M

    Chem P42

    l last year for p42 A was 60 p41 and p43 was 55
  6. M

    Chem P42

    check Mr. manoj status on fb he says A around 55-58
  7. M

    Chem P42

    well my teacher says its gonna be around 55-58 lets hope for a low gt :p
  8. M

    Chemistry Paper 4-theory- doubts =D

    Im good alhumdu-li-allah :D N u welcome :)
  9. M

    Chemistry Paper 4-theory- doubts =D

    Using NaoH + I2 (iodine) Ethanol gives yellow ppt and no rxn with methanol
  10. M

    Chemistry Paper 4-theory- doubts =D

    Hey dude how are you ... Long time no see in tutions :p So about ur question im gonna explain it to u even though it makes no sesnse at all Look at step 1 ... a is for h2o2 b is for I- and c is for H+ In the first step h2o2 has appered once so right 1 in the first row of a I- has appered one...
  11. M

    AS LEVEL BIOLOGY... discuss here AS students only :)

    plz people dont discuss the questions because ther are some losers who want the questions of the paper remember this is cheating and such a losers will higher the gt :)
  12. M

    AS Biology paper 22 May 13th 2013

    it was just fine expecting low gt and i wrote extrs stuff too but not in the answer space i wrote it in he blank page and in the spaces with writing to which question are these answers because i remeber my teacher saying its important to use blank pages if u write right stuff they will give u...
  13. M

    AS LEVEL BIOLOGY... discuss here AS students only :)

    co2 + h2o --->h2co3 h3co3---->H+ + HCO3 HbO + H+ ----> HHb when co2 concentration increase it dissolve in water to give carbonic acid therefore increasing H+ ions in the blood H+ lowers the pH of the blood and makes the blood acidic.. to restore the normal PH of the blood : haemoglobin now has...
  14. M

    AS LEVEL BIOLOGY... discuss here AS students only :)

    phosphoipids ... form the bilayer and a barrier to polar molecule cholestrol..maintain the fluidity of the membrane and maintain mechanical stability glycolipids...staiblise the membrane structure protein.. act as transport channels glycoprotiens...receptors to chemicals and help in...
  15. M

    AS LEVEL BIOLOGY... discuss here AS students only :)

    dude its better to understand whats is resolution .. if u understand it u can tell which has the better resolution :cool:
  16. M

    AS LEVEL BIOLOGY... discuss here AS students only :)

    O.O NEVER SAW SUCH A THING ?!
  17. M

    AS LEVEL BIOLOGY... discuss here AS students only :)

    r resolution means how much a lens can distinguish between two different structures lying next to each other i.e resolution of 200nm mean the lense can distinguish between two structure with 200nm space between them n 20nm means the lense can distinguish between two structure with 20nm space...
  18. M

    AS LEVEL BIOLOGY... discuss here AS students only :)

    it is in the syllabus of A2 but its always good to know more so u can understand better :)
  19. M

    AS LEVEL BIOLOGY... discuss here AS students only :)

    facilitated diffusion... the movement of larg polar molecules from regions of their high concentartion to regions of their lower concentartion via special protien channels on the cell surface membrane.... thats it
  20. M

    AS LEVEL BIOLOGY... discuss here AS students only :)

    atp-powered proton pumps actively transport H+ ions outside the cell this creates a nagtive charge in the guard cells causing K+ channels to open n K+ IONS diffuse into the guard cells down an electrochemical gradient> the high concentration of K+ ion lowers water potential inside the guard...
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