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

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    (Original post by jsmith6131)
    or is it just

    toxin production
    damaging host cells
    Those 2 are on the spec, so I'd just learn them.
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    (Original post by jsmith6131)
    or is it just

    toxin production
    damaging host cells
    Ive got the above two, only more specific as to damage to host cells:

    1. Rupturing host cell to release nutrients
    2. Breaking down nutrients in host cell for own use
    3. Replicating inside host cell, thus bursting it.
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    (Original post by liviaaa)
    Ohh so it means the variable region changes shape on the different antibodies! I thought it meant on 1 antibody it kept changing shape. Thanks!
    Also always think of proteins because antibodies are made out of them, so talk about the primary and tertiary structure etc. and how this changes the variable region.
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    Describe the structure of the cell - surface membrane.
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    Define diffusion.
    Is it passive or active transport?
    What is diffusion proportional to?
    Describe facilitated diffusion.
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    Anyone understand monoclonal antibodies in relation to pregnancy tests? Just something thats always bugged me.

    The application area has antibodies for hCG bound to coloured bead, when urine is applied, any hCG in it binds to antibody on beads, forming antigen-antibody complex.

    But then, it moves up the stick, carrying beads with it, to the test strip with immobilised antibodies on it.

    Why more antibodies? Do they bind to these too, whilst still bound to appliction area antibodies? Why does it need this to turn strip blue?
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    (Original post by Tericon)
    Anyone understand monoclonal antibodies in relation to pregnancy tests? Just something thats always bugged me.

    The application area has antibodies for hCG bound to coloured bead, when urine is applied, any hCG in it binds to antibody on beads, forming antigen-antibody complex.

    But then, it moves up the stick, carrying beads with it, to the test strip with immobilised antibodies on it.

    Why more antibodies? Do they bind to these too, whilst still bound to appliction area antibodies? Why does it need this to turn strip blue?
    I hate these questions. They have these kind of things for enzymes too.
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    (Original post by Sparkly-Star)
    Define diffusion.
    Is it passive or active transport?
    What is diffusion proportional to?
    Describe facilitated diffusion.
    The net passive movement of a substance from an area of higher concentration to an area of lower concentration, down a concentration gradient.

    Proportional to??

    Facilitated diffusion: Net passive movement of a large or charged molecule from an arera of higher conc to an area of lower conc, down concentration gradient, using protein channels and carrier protiens in the membrane.
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    (Original post by Sparkly-Star)
    I hate these questions. They have these kind of things for enzymes too.
    I haven't seen one on a paper yet...so either they're not that mean...or....IT'S COMING :eek:
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    (Original post by Tericon)
    I haven't seen one on a paper yet...so either they're not that mean...or....IT'S COMING :eek:
    I have seen one on one of the papers. So hopefully it won't come up again cos I'm just gonna memorize the answers.
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    (Original post by Sparkly-Star)
    I have seen one on one of the papers. So hopefully it won't come up again cos I'm just gonna memorize the answers.
    Which one?
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    (Original post by Tericon)
    I haven't seen one on a paper yet...so either they're not that mean...or....IT'S COMING :eek:

    (Original post by Sparkly-Star)
    I have seen one on one of the papers. So hopefully it won't come up again cos I'm just gonna memorize the answers.
    They wouldn't ask specifically about a pregnancy test. They could use it in context, but would only lead us to having to talk about basic monoclonal antibiody knowledge.
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    Define osmosis.
    How would you find the water potential of a tissue?
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    (Original post by Tericon)
    The net passive movement of a substance from an area of higher concentration to an area of lower concentration, down a concentration gradient.

    Proportional to??

    Facilitated diffusion: Net passive movement of a large or charged molecule from an arera of higher conc to an area of lower conc, down concentration gradient, using protein channels and carrier protiens in the membrane.
    I think she meant that diffusion rate is proportional to the concentration of the substance on either side (con. gradient)
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    (Original post by sanaindaclub)
    I think she meant that diffusion rate is proportional to the concentration of the substance on either side (con. gradient)
    Thanks
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    (Original post by eliteDNA)
    okay il answer my own question then...

    -Firslty gluscoe is absorbed through into the epithelial cells by facilitated diffusion down a conc. gradient.
    -Then Na ions are ACTIVELY pumped out of epithelial cells into lumen
    -Meaning that conc. of Na is higher in lumen
    -Glucose then diffuses passivley into epithelial cells via the Na glucose co-transporter.
    -Conc. of glusoce high in the epithelial cell, so it diffuses into bloodstream.
    (Original post by EffKayy)
    Okay.
    The basic points you need to know:

    1)Sodium ions are actively transported out of the epithelial cells into the blood.
    2) This creates a higher concentration of sodium ions in the lumen of the intestine than the epithelial cells
    3) Sodium ions move into the epithelial cells, but when it does, glucose is carried with it, so a carrier protein is also used
    4) Glucose is transported to the blood via facilitated diffusion.

    Thanks guys!
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    Cardiac cycle

    atrial systole-Atria contract. Pressure in the atria is higher than in the ventricles so the AV valves open causing the blood to move out of the atria
    and into the ventricles. Atria volume decreases, ventricles volume increases

    Ventricular systole-Ventricles contract from base up. Pressure in the ventricles is higher than the atria so the AV valves close to stop backflow. The pressure is the ventricles is also
    higher than the aorta so the SL valves open causing the blood to move into the aorta. Volume in the ventricles decreases, volume in the aorta increases

    Diastole-Both ventricles and atria relax. Pressure is low

    Could anyone tell me if this is enough for the whole of the cardiac cycle. Also, does anyone know what is happening to the AV and SL valves at diastole (are they open or closed). Thanks
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    Ugh, feeling fine about the exam but only just found out there are answers to the examination questions in the AQA book!
    ****! Why didnt they put the answers in the book the ****'s!

    Also, why is Unit 2 a doss when Unit 1 has the immunology questions (which seems to be the harest part of the course)
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    Rip biol1 :e
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    Can anyone please help with this...its maths and my brain just shuts down:

    Calculate how much risk is increased by smoking 25 a day compared with not smoking at all:

    Not smoking: 0.17 25 a day: 4.17
 
 
 
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