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  1. Karim Nabil

    A level Biology: Post your doubts here!

    yes, anyways we have finished p1... so no need further explanations :P
  2. Karim Nabil

    A level Biology: Post your doubts here!

    infolded to allow expansion for increasing S.A not for gaseous exchange yes to increase inflammation and make mast cells release histamine to attract nearby neutrophils.
  3. Karim Nabil

    A level Biology: Post your doubts here!

    Because at the beginning of the reaction, there are many substrate molecules to bind to the active site, inhibition is reversible(temporary). So many E-S complex is formed.
  4. Karim Nabil

    A level Biology: Post your doubts here!

    Because at the beginning of a reaction, there shouldn't be any free active sites because many substrate molecules are present, instead more E-S complex forming so answer is B
  5. Karim Nabil

    A level Biology: Post your doubts here!

    Take off anomalous results and calculate average, then try eliminating wrong ones and observe the remaining options.
  6. Karim Nabil

    A level Biology: Post your doubts here!

    They bind to the mast cells for triggering them to release histamine and cause inflammation. Then an immune response is stimulated, attracting nearby neutrophils to the antigen.the neutrophil recognize and then attach to the antigen, engulf it by phagocytosis, then it is digested and released...
  7. Karim Nabil

    A level Biology: Post your doubts here!

    Histamine released when pathogen invade mast cells, then immune response stimulated and afterwards, antibody binds with the antigen. Trachea isn't the site of gaseous exchange, so foldings is not needed. Revise the straight chain structure of glucose! No, along with hydrogen ions, sucrose is...
  8. Karim Nabil

    A level Biology: Post your doubts here!

    sure.. so first question is D as after antigen binding to antibody no histamine should be released 2nd, inner membrane folded to expand as it could easily stretch and recoil, answer is A 3rd, glucose and fatty acids contains c=o, but glycerol doesn't, answer is A 4th, -reduction division is only...
  9. Karim Nabil

    A level Biology: Post your doubts here!

    yes 200%
  10. Karim Nabil

    A level Biology: Post your doubts here!

    disulphide bonds are the most strongest covalent bond, then comes ionic then hydrogen then hydrophobic interaction disulphide bonds broken by reducing agents hydrogen bonds broken by high temperatures or ph change ionic bonds broken by ph change
  11. Karim Nabil

    A level Biology: Post your doubts here!

    if no actual length given then; 10*1000=x10000 is the magification.
  12. Karim Nabil

    Biology P21 GT

    isa :D
  13. Karim Nabil

    Biology P21 GT

    i think plus my work i have added them; i don't remember for now :P
  14. Karim Nabil

    Biology P21 GT

    guys last question was talking about coordination of chambers for systemic circulation and pulmonary circulation, so you'll have to talk about right camber carrying deoxygenated blood with detailed info and left carrying oxygenated, state difference b/w systemic and pulmonary circulations only...
  15. Karim Nabil

    English (0510) LISTENING TRACKS oct/nov 2013

    http://papers.xtremepapers.com/CIE/Cambridge%20IGCSE/Hindi%20as%20a%20Second%20Language%20(0549)/
  16. Karim Nabil

    A level Biology: Post your doubts here!

    Yes.. It was an easy paper, with some exceptions only; like antibody production, i thought for a while it is an immune reponse but was able to distinguish that immunoglobulines produced by protein synthesis later :/ , (feeling irritated right now)
  17. Karim Nabil

    A level Biology: Post your doubts here!

    P21?!
  18. Karim Nabil

    CIE Oct/Nov 2013 papers with marking schemes

    http://papers.xtremepapers.com/CIE/Cambridge%20IGCSE/Malay%20-%20Foreign%20Language%20(0546)/
  19. Karim Nabil

    A level Biology: Post your doubts here!

    ok... whatever :D Best of luck for you too ;)
  20. Karim Nabil

    A level Biology: Post your doubts here!

    no comment..such a retard -_- i don't want to have diabetes... i've exams to sit for.. well, i don't even look at the markscheme...erghh :mad: i don't blame you for such a stupidity but blame myself for answering such a retard.
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