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    (Original post by mobius323)
    Cheers mate. I don't suppose you happen to have the Exam Reports too?
    Got June 10, but only as a hard copy. Check the internet if you haven't, they are probably lurking around somewhere lol

    (Original post by darkiee)
    What I Have Noticed, State the Bleeding obvious in your answer, even if it looks like you would b repeating questions, some of them answer DO get you marks. I have met a lot of question like that, i would never have thought have to put it in cause its stupid and they are actually in the mark scheme
    The best thing is to take no risks AT ALL. Put down every little thing you know that is relevant to the ques. You don't get marked down for putting extra AFAIK. That's what I'm going to do anyway.
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    i know this may sound stupid but what is ANTIBIOTIC RESISTANCE
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    (Original post by InItToWinItGetIt?)
    Got June 10, but only as a hard copy. Check the internet if you haven't, they are probably lurking around somewhere lol



    The best thing is to take no risks AT ALL. Put down every little thing you know that is relevant to the ques. You don't get marked down for putting extra AFAIK. That's what I'm going to do anyway.
    You can't get marked down for extra information. Examiners have to mark positively, not negatively. You start off with zero and gain marks. You don't start with 90 and lose marks.


    (Original post by xshopoholicx)
    i know this may sound stupid but what is ANTIBIOTIC RESISTANCE
    When bacteria are exposed to antibiotic drugs, bacteria who don't have genes giving resistance to the drug will die out, but bacteria with resistance will survive and reproduce. Overall, the ones without resistance die out, and this gives rise to antibiotic resistance as the gene for resistance becomes more common.
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    (Original post by LibbyU)
    They're linked because T cells are needed to activate B cells so that they can produce antibodies. But the T cells need to be activated first to divide into T memory cells and active T cells in order to activate the B cells.
    Its confusing because on page 103 of the orange book it shows two diagram; one involving antigen presenting cell and the other involving B cell as an antigen presenting cell. If T cell initiates B cell then how is B cell an antigen presenting cell..?
    :confused:
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    (Original post by sounv001)
    Basically i think you need to mention:
    -pre-mRNA- when the RNA is transcribed from the DNA. This has all the DNA from the gene- so introns and exons.
    -Exons are the parts that code for the amino acids, so splicosome enzymes cut the exons out of the mRNA strand (splicing)
    -Exons can then be arranged in various different sequences to form a single strand
    So same gene can code for lots of different proteins.

    Theres also something in the book about capping the end of RNA strands so its not attacked by enzymes, but i dont know if thats really relevant for this question
    Capping each end allows for greater mRNA stability and it also facilitates ribosome-mRNA binding but you probably don't have to know that.
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    (Original post by idiotone)
    Its confusing because on page 103 of the orange book it shows two diagram; one involving antigen presenting cell and the other involving B cell as an antigen presenting cell. If T cell initiates B cell then how is B cell an antigen presenting cell..?
    :confused:
    Basically they are two separate diagrams and the one on the left is needed FIRST in order for the diagram on the right to happen.

    The diagram on the left is how the T cells are made. The macrophage becomes an APC and then it binds with a T helper cell, causing it to become activated and divide into T memory cells and active T helper cells. Then... THESE active T helper cells (the same ones that were just made) bind to B cells that are presenting antigens and stimulate the B cell to divide and form antibodies.

    The B cell is an antigen presenting cell because it has binded to a pathogen that has antigens on it. For example a bacteria... the bacteria has antigens and these have attached to the B cell and the B cell presents the antigens. These antigens act as a signal so that the activated T helpers (produced in the diagram on the right) can bind to the B cell in order to help it to produce antibodies.
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    (Original post by mobius323)
    You can't get marked down for extra information. Examiners have to mark positively, not negatively. You start off with zero and gain marks. You don't start with 90 and lose marks.
    Yeah I know. By ''not take any risks at all'', I meant don't be afraid of putting something down. Don't think oh this is obvious, there won't be a mark for it. Put everything down.

    I worded it very badly though lol
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    (Original post by LibbyU)
    Basically they are two separate diagrams and the one on the left is needed FIRST in order for the diagram on the right to happen.

    The diagram on the left is how the T cells are made. The macrophage becomes an APC and then it binds with a T helper cell, causing it to become activated and divide into T memory cells and active T helper cells. Then... THESE active T helper cells (the same ones that were just made) bind to B cells that are presenting antigens and stimulate the B cell to divide and form antibodies.

    The B cell is an antigen presenting cell because it has binded to a pathogen that has antigens on it. For example a bacteria... the bacteria has antigens and these have attached to the B cell and the B cell presents the antigens. These antigens act as a signal so that the activated T helpers (produced in the diagram on the right) can bind to the B cell in order to help it to produce antibodies.
    So why is patient infected with TB more likely to develop symptom if they are infected with HIV? (3) Is it because HIV invades T helper which lowers the activity of macrophages which means its more likely that the bacterial cell will not be destroyed..?
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    (Original post by idiotone)
    So why is patient infected with TB more likely to develop symptom if they are infected with HIV? (3) Is it because HIV invades T helper which lowers the activity of macrophages which means its more likely that the bacterial cell will not be destroyed..?
    Yea, its because like you said with HIV, the virus directly targets the white blood cells and reduces the number of T cells that would have fought against the TB bacterium. HIV = reduces T cells. The lower the number of T cells = the weaker the persons immune system, and the less able they are to fight infections against pathogens such as TB
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    Please could someone go over some of the forensic stuff? I'm fine with body temperature and rigor mortis but what about decomposition? I mean what do we need to know for that? I can't imagine what kind of questions they could ask on it. any ideas?

    Also could someone please explain insect evidence? I only understand the very basics
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    can anyone explain pollen in peat bogs please?
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    Suggest why the cloning of lymphocytes by mitosis is important in the production of an antibody
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    why is hair used to make a DNA profile?

    Is it cause it contains our genetic material which is unique to other people..?
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    (Original post by LibbyU)
    Please could someone go over some of the forensic stuff? I'm fine with body temperature and rigor mortis but what about decomposition? I mean what do we need to know for that? I can't imagine what kind of questions they could ask on it. any ideas?

    Also could someone please explain insect evidence? I only understand the very basics
    Forensic entomology is used to determine the time of death due to following ways :

    1) Identifying the maggots stage of development with reference to the life cycle if the fly.
    2) Pathologist know at what stage each insect occupies the body.
    3) If temperature of the body has remained constant, the age of maggot growing in it can be determined by their starting length and the temperature of the part of the body they grew in .
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    (Original post by idiotone)
    Forensic entomology is used to determine the time of death due to following ways :

    1) Identifying the maggots stage of development with reference to the life cycle if the fly.
    2) Pathologist know at what stage each insect occupies the body.
    3) If temperature of the body has remained constant, the age of maggot growing in it can be determined by their starting length and the temperature of the part of the body they grew in .
    thank you
    i dont really understand the third point though?

    also how do you calculate the efficiency of energy transfers between trophic levels? anyone know??????
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    (Original post by xshopoholicx)
    Suggest why the cloning of lymphocytes by mitosis is important in the production of an antibody
    So a large amount of genetically-identical lymphocytes are produced, which means a lot of of antibodies specific to the antigen present are produced meaning the infection can be fought off better.
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    (Original post by pearlover)
    can anyone explain pollen in peat bogs please?
    *Pollen in peat bogs are used to show how temperature changed over thousands of years unlike temperature records which are only used for short term global temperature change

    I've revised this from my CGP guide:

    1) Pollen is preserved in peat bogs [acidic wetland areas]
    2) Peat bogs accumulate in layers so the age of the preserved pollen increases with depth
    3) Scientists can take cores from the peat bog and extract pollen grains from different aged layers. They can identify the plant species the pollen came from.
    4) Only fully grown [mature] plant species produce pollen, so the samples only show the species that were successful at the time.
    5) Scientists know the climates that different plant species live in now. When they find preserved pollen from similar plants, it indicates that the climate was similar when that pollen was produced.
    6) Because plant species vary with climate the preserved pollen will vary as climate changes over time
    7) so a gradual increase in pollen from a plant species that's more successful in a warmer climates would show a rise in temperature [a decrease in pollen from a plant that needs cold conditions would show the same thing]

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    Burr, How is revision going everyone, I really dont know what to read anymore . I have doen everything I think I can any suggestion?
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    Can anyone please upload the 3 past papers? Or link me where they are. I've done them before, so I only have hard copies with answers in it..
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    (Original post by Phenylethylamine_)
    *Pollen in peat bogs are used to show how temperature changed over thousands of years unlike temperature records which are only used for short term global temperature change

    I've revised this from my CGP guide:

    1) Pollen is preserved in peat bogs [acidic wetland areas]
    2) Peat bogs accumulate in layers so the age of the preserved pollen increases with depth
    3) Scientists can take cores from the peat bog and extract pollen grains from different aged layers. They can identify the plant species the pollen came from.
    4) Only fully grown [mature] plant species produce pollen, so the samples only show the species that were successful at the time.
    5) Scientists know the climates that different plant species live in now. When they find preserved pollen from similar plants, it indicates that the climate was similar when that pollen was produced.
    6) Because plant species vary with climate the preserved pollen will vary as climate changes over time
    7) so a gradual increase in pollen from a plant species that's more successful in a warmer climates would show a rise in temperature [a decrease in pollen from a plant that needs cold conditions would show the same thing]

    thank you soo much! x
 
 
 
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