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AQA BIOL1 Biology Unit 1 Exam - 16th May 2011 Watch

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    (Original post by swiftylol)
    Why's a buffer solution used for ultracentrifugation?
    To maintain a constant pH level
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    (Original post by animal*nature)
    Why when the second time you are exposed to a pathogen you respond more quickly to the pathogen
    First time you have to deal with it by doing phagocytosis, humour and celluar. Memory cells produced. Second time the process is more specific. T-memoy remember the shape of the antigens so recognise faster. B-memory remember how to produce the antibody so the process is faster.
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    So Ph doesnt alter organelles?
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    (Original post by Jubilee~)
    Lmaaaaao okay so i'm ok
    for a moment then i thought i'd learn the wrong thing :eek:
    was about to jump off the nearest building
    LOL I think I'll do be doing that come the end of the exam tomorrow. :cool:
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    (Original post by animal*nature)
    Why when the second time you are exposed to a pathogen you respond more quickly to the pathogen
    because there's memory cells circulating the blood which will then rapidly divide into plasma cells that will make antibodies complimentary to the antigen of the pathogen. Therefore it'll kill the pathogen more rapidly
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    Just going through past papers and their MS, posting stuff I don't understand, anyone please help with this?

    Calculate the number of cases of diarrhoea confirmed as being caused by
    Campylobacter jejuni in men in 1998.

    60,000 confirmed cases, ratio: more frequent in males than female, ratio = 1.5:1

    I know the answer, but how do you work it out? I thought it'd be 60000/1.5, but thats gives 40000, which is apparently not the answer....

    Thanks
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    anyone got questions on monosaccharides and breaking down of starch and stuff :/
    HATE HATE HATE it :|
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    (Original post by animal*nature)
    Why when the second time you are exposed to a pathogen you respond more quickly to the pathogen
    because the first time you experienced the pathogen your b-cells produced memory cells that remember the antigen, and already have antibodies that have the complementary shape to the antigen so the next time the body is infected with the same pathogen they can quickly release these antibodies instead of having to wait for the t-cells to stimulate the b-cells then the b-cells make plasma cells which make the memory cells, its already done so its quicker
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    (Original post by Sighrawr)
    Hah I know, but it doesn't mean poor grammar is acceptable. Without English we would not be able to communicate in these bloody biology exams.
    As long as we don't have to remember how to spell diarrhea...
    (Original post by Jubilee~)
    yeah, you said "Cholera causes the chloride ion channels to open in the eptihelial cells of the small intestines. The chloride ions then move out of the cells into the lumen, lowering the water potenial of the lumen. Water therefore follows out of the blood into the lume from a high water potential to low, by osmosis"

    so what i said was it'd be good if you said before the last sentence that water moves from epethelial into the lumen which IN turn causes water to move from the blood into the epethelial.

    am i making any sense
    Makes more sense if you said that the epithelial has less water because of the osmotic movement into the lumen lowers the water potential in the epithelial so water from blood moves there. :O
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    (Original post by Tericon)
    Just going through past papers and their MS, posting stuff I don't understand, anyone please help with this?

    Calculate the number of cases of diarrhoea confirmed as being caused by
    Campylobacter jejuni in men in 1998.

    60,000 confirmed cases, ratio: more frequent in males than female, ratio = 1.5:1

    I know the answer, but how do you work it out? I thought it'd be 60000/1.5, but thats gives 40000, which is apparently not the answer....

    Thanks
    (60,000/2.5) x 1.5
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    About 12 hours until we open the paper.......it will be the commencement of this summer massacre commited by me
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    (Original post by BeejTheone)
    (60,000/2.5) x 1.5
    why do you have to divide by 2.5?
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    (Original post by Rickesh)
    Why you retaking, thats an A?
    haha that was a practice paper :P I got a c 68 UMS when i first did it
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    (Original post by Rahul.S)
    About 12 hours until we open the paper.......it will be the commencement of this summer massacre commited by me
    That's the spirit!
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    (Original post by ??????????????????)
    As long as we don't have to remember how to spell diarrhea...


    Makes more sense if you said that the epithelial has less water because of the osmotic movement into the lumen lowers the water potential in the epithelial so water from blood moves there. :O

    i hate spelling diarrhea LOOOOOOOOOOL & that's what i said in my previous post and i cba repeat myself
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    hmm early night or revision till a bit later
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    (Original post by Rickesh)
    why do you have to divide by 2.5?
    Ratio is 1.5:1 so 1.5 + 1=2.5
    For every 2.5 one is 1.5 and that is why.
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    (Original post by Rickesh)
    why do you have to divide by 2.5?
    Its ratio question so its basically maths. 1+1.5 = 2.5 This is the total of all cases.

    so you divide to get 1 and then multiply by 1.5 to get 1.5 (which is case for men)
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    (Original post by ??????????????????)
    As long as we don't have to remember how to spell diarrhea...


    Makes more sense if you said that the epithelial has less water because of the osmotic movement into the lumen lowers the water potential in the epithelial so water from blood moves there. :O
    Diarrheoa. I just learned how to spell it right for the first time in my life today.
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    Early night!

    Thats what im doing PEACE PEOPLE! gl!
 
 
 
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