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AQA Biology AS New Spec - 26th May and 7th June Watch

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    (Original post by The Panic Queen)
    For set 2 paper 2
    could someone explain how to do Q3.4??? I don't understand why it is -0.34
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    Edit: the value is a minus as the gradient is negative.
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    could someone explain the process of hybridisation please???
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    (Original post by Wisteria_xo)
    On a question it asked how the reduced elasticity of the lungs causes breathing difficulties, and one of the marking points was that lungs cannot fully inflate (reduced lung capacity)- which I understand.
    However the other marking but was that breathing out would no longer be passive? Which i don't understand at all
    I think what this means is that normally we don't use forced expiration: our intercostal muscles do not normally contract during expiration. This is because the elasticity of the alveoli is enough to push the air out: the alveloi sort of recoil. However, reduced elasticity renders this mechanism ineffective and so we need to rely on forced expiriation which means expiration is no longer passive
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    (Original post by Eden_)
    could someone explain the process of hybridisation please???
    It's not part of the AS content as to the specification although we did learn it in class.
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    (Original post by Eden_)
    could someone explain the process of hybridisation please???
    Hybridisation is what we use to determine the degree of 'relatedness' between two organisms. The first step is to obtain DNA from the two organisms. We then break the hydrogen bonds and separate the DNA strands by heating. We then allow the separated DNA strands to mix. Hybrid DNA forms which contains strand of DNA from one organism and a strand of DNA from the other. We now attempt to separate these two strands via heating. The higher the temperature required to separate the strand, the more closely related the two organisms are as their must be more Hydrogen bonds so there must be more complementary base pairs and so the base sequences of dna must be more similar
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    (Original post by Lola1244)
    Hybridisation is what we use to determine the degree of 'relatedness' between two organisms. The first step is to obtain DNA from the two organisms. We then break the hydrogen bonds and separate the DNA strands by heating. We then allow the separated DNA strands to mix. Hybrid DNA forms which contains strand of DNA from one organism and a strand of DNA from the other. We now attempt to separate these two strands via heating. The higher the temperature required to separate the strand, the more closely related the two organisms are as their must be more Hydrogen bonds so there must be more complementary base pairs and so the base sequences of dna must be more similar
    Thank you so much!!!😃
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    How can Biologists use protein structure to investigate the relationship between differentspecies?
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    (Original post by LightsOut.)
    How can Biologists use protein structure to investigate the relationship between differentspecies?
    Look at sequence of amino acid - primary structure, in same protein . The more similar the sequence , the closer the relationship

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    Am I correcting in thinking the first paper was only on the first 2 units (even though AQA said the papers would be mixed) and so paper 2 will be on Unit 3 and 4?
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    (Original post by Lemauricien)
    Look at sequence of amino acid - primary structure, in same protein . The more similar the sequence , the closer the relationship

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    Cheers.
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    (Original post by Oddwatermelon)
    Am I correcting in thinking the first paper was only on the first 2 units (even though AQA said the papers would be mixed) and so paper 2 will be on Unit 3 and 4?
    You Only Learn Units 1 and 2 In Aqa As Biology.
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    (Original post by Oddwatermelon)
    Am I correcting in thinking the first paper was only on the first 2 units (even though AQA said the papers would be mixed) and so paper 2 will be on Unit 3 and 4?
    The paper seemed to be almost solely on Unit 1 and 2, but that's purely a coincidence. But, that does mean that there is a high chance that this paper tomorrow will contain mostly Unit 3 and 4 content.
    (Saying that, it's hard to tell as AQA are very unpredictable, they may surprise us with even more enzymes).
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    (Original post by Lola1244)
    I think what this means is that normally we don't use forced expiration: our intercostal muscles do not normally contract during expiration. This is because the elasticity of the alveoli is enough to push the air out: the alveloi sort of recoil. However, reduced elasticity renders this mechanism ineffective and so we need to rely on forced expiriation which means expiration is no longer passive
    Helped so much thank you
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    (Original post by Productivity)
    The paper seemed to be almost solely on Unit 1 and 2, but that's purely a coincidence. But, that does mean that there is a high chance that this paper tomorrow will contain mostly Unit 3 and 4 content.
    (Saying that, it's hard to tell as AQA are very unpredictable, they may surprise us with even more enzymes).
    Wait... I seem to be missing something. What is in Unit 3 and 4? Is it not A2 content?
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    (Original post by LightsOut.)
    Wait... I seem to be missing something. What is in Unit 3 and 4? Is it not A2 content?
    The AS content is split up into 4 units on the specification.
    1. Biological molecules.
    2. Cells.
    3. Organisms exchange substances with their environment.
    4. Genetic information, variation and relationships between organisms.

    We weren't talking about the exam papers which are also named Unit 1-4, in case that is where the confusion lies.
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    predictions what's likely to come up tomorrow? and how prepared you feeling, I'm kinda nervous
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    Anyone simple can explain translocation?
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    Does anyone know the key points of how tissue fluid is formed?
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    (Original post by _naomi0511)
    Does anyone know the key points of how tissue fluid is formed?
    1. High hydrostatic pressure at the arteriole end of the capillary bed causes fluid and small molecules to be pushed out of the capillary into the surrounding tissue, (as the pressure is lower there)

    2. Plasma proteins are too large and are therefore not pushed through the capillary and remain inside it. These are soluble and therefore lower the water potential.

    3. Some water will therefore move back into the capillary via osmosis

    Also as a side note it is good to know that any excess tissue fluid is drained by the lymphatic system
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    (Original post by JakeRStudent)
    1. High hydrostatic pressure at the arteriole end of the capillary bed causes fluid and small molecules to be pushed out of the capillary into the surrounding tissue, (as the pressure is lower there)

    2. Plasma proteins are too large and are therefore not pushed through the capillary and remain inside it. These are soluble and therefore lower the water potential.

    3. Some water will therefore move back into the capillary via osmosis

    Also as a side note it is good to know that any excess tissue fluid is drained by the lymphatic system

    Thank you so much!
 
 
 
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