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AQA BIOL5 Biology Unit 5 Exam - 22nd June 2011 watch

  • View Poll Results: Are you resitting this unit?
    YES!
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    NO!
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    (Original post by Destroyviruses)
    http://store.aqa.org.uk/qual/gce/pdf/AQA-2410-W-SP.PDF

    Start reading from page 6
    Lol :ahee:
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    (Original post by llamalad200)
    Is anyone else just not bothering to prepare for the synoptic essay?

    I'm just going to have a blind stab at it when i finish the other questions
    I'll probably end up doing this too. I might do another essay and read through the spec though.
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    (Original post by tehsponge)
    Lol :ahee:
    Its not that much! I've gott them all printed. Unit 1-5 How rad am I?
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    (Original post by tehsponge)
    I'll probably end up doing this too. I might do another essay and read through the spec though.
    Im revising unit 5 then will do a little staring at my mind map.
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    7 (b) (i) You could use an optical microscope and a slide of stained muscle tissue to find the
    diameter of one of the muscle fibres. Explain how.

    Mark scheme says:
    Measure with graticule/eyepiece scale;
    Calibrate against something of known size:
    OR
    Estimate/measure field diameter with a scale;
    Estimate number of fibres to cover diameter;

    Eh? I wrote an answer to do with measuring the diameter of the image then using the magnification= image/object calculation...
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    (Original post by tehsponge)
    7 (b) (i) You could use an optical microscope and a slide of stained muscle tissue to find the
    diameter of one of the muscle fibres. Explain how.

    Mark scheme says:
    Measure with graticule/eyepiece scale;
    Calibrate against something of known size:
    OR
    Estimate/measure field diameter with a scale;
    Estimate number of fibres to cover diameter;

    Eh? I wrote an answer to do with measuring the diameter of the image then using the magnification= image/object calculation...
    That's exactly what I wrote as well! The mark schemes are so dodgy...the specimen one got an action potential question completely wrong (said sodium channels diffuse out when an impulse arrives).
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    Question 10
    There were occasional essays that were a pleasure to read. They had accurate and detailed
    content and presented the underlying argument lucidly and coherently. Many of the essays
    seen, however, were of poor quality.

    I wonder why, AQA.
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    What are people learning for the 'stretch and challenge' off spec aspects to add into essays, I need a few things that can most likely be applied to any essay topic that could come up
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    (Original post by LeBubbled)
    That's exactly what I wrote as well! The mark schemes are so dodgy...the specimen one got an action potential question completely wrong (said sodium channels diffuse out when an impulse arrives).
    I know and the examiners report had the cheek to say that using the calculation was impractical :mad:

    How is "Estimate/measure field diameter with a scale;
    Estimate number of fibres to cover diameter;"

    more practical than using a simple calculation which gives the EXACT diameter?! wtf?! :mad:
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    (Original post by thevoicesarecallin)
    What are people learning for the 'stretch and challenge' off spec aspects to add into essays, I need a few things that can most likely be applied to any essay topic that could come up
    If you have the Nelson Thornes textbook, I've found that sometimes the application questions have some useful things.
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    (Original post by tehsponge)
    7 (b) (i) You could use an optical microscope and a slide of stained muscle tissue to find the
    diameter of one of the muscle fibres. Explain how.

    Mark scheme says:
    Measure with graticule/eyepiece scale;
    Calibrate against something of known size:
    OR
    Estimate/measure field diameter with a scale;
    Estimate number of fibres to cover diameter;

    Eh? I wrote an answer to do with measuring the diameter of the image then using the magnification= image/object calculation...
    I think, tahts what it means by "eye piece scale"
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    I haven't revised at all for the exam, I'm dreading the synoptic especially!
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    (Original post by thevoicesarecallin)
    What are people learning for the 'stretch and challenge' off spec aspects to add into essays, I need a few things that can most likely be applied to any essay topic that could come up
    Go through the spec and google stuff you find interesting.
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    (Original post by leesh18)
    can someone please outline for me the mentrual cycle and what we need to know
    thank you
    This seemed to help someone a few weeks ago so I'll just copy/paste it from then:

    There's four hormones: FSH, Oestrogen, LH and Progesterone.

    The first hormone is FSH. This is released from the pituitary gland, and stimulates the follicles to grow.

    As the follicles are growing, they begin to release small amounts of oestrogen. Oestrogen's job is the make the uterus thicker and stronger. The more oestrogen, the thicker it gets. Another thing about oestrogen is that in small amounts, is inhibits FSH and LH release. However, at a critical point, the oestrogen stimulates FSH and LH release.

    So when oestrogen reaches it's critical point, it causes LH to be released from the pituitary gland. LH causes ovulation. - the egg being released from its follicle. When the egg leaves the follicle, the follice bcomes a corpus luteum. It's basically just an empty follice.

    The empty follicle releases progestrone Progesterone has two effects. Firstly, it inhibits FSH and LH. Also, since the follicle is now a corpus luteum, it stops producing oestrogen. So for ease, imagine at this point there is only Progesterone. Progesterone's second effect is that it maintains the strength of the uterus, awaiting pregnancy. If the egg isn't fertilised in time, the progesterone being released from the corpus luteum 'runs out'. It stops being released, so FSH and LH stop being inhibited.

    FSH is once again released from the pituitary gland, and it all starts over.
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    (Original post by angel1992)
    i dont understand why primers are needed in pcr, when in dna replication dna polymerase can just join up bases to the chain without primers?
    because you can isolate a specific gene....
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    9 (d) The scientists analysed the DNA on the Y chromosome and the DNA in the
    mitochondria of the Swedish wolves. They concluded that the Swedish wolf population
    descended from one male wolf from Finland and one female wolf from Russia.
    9 (d) (i) Explain why DNA on the Y chromosome helped them to reach this conclusion.

    answer:

    Y chromosome inherited/comes from male parents/only found in males;

    What?! That doesn't even follow from the question...
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    someone help me on Q (6)(c)ii) june 2010 - why can't you write oncogenes?
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    50/75 for the June 2010 paper (didn't do the essay). That's 66% so I just scraped an A
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    (Original post by Cyanohydrin)
    because you can isolate a specific gene....
    In DNA replication, DNA doesn't completely separate into two strands, so there is a short double stranded section which can act as an initiator region for DNA polymerase - this section is then removed once replication is complete. All the primer does is provide this initiator region as polymerase cannot act unless there is a double stranded section. Without the primer the free nucleotides could not be joined into a complementary strand as the two strands are completely separate
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    (Original post by tehsponge)
    50/75 for the June 2010 paper (didn't do the essay). That's 66% so I just scraped an A
    So... what's with the face? That's excellent without the essay.
 
 
 
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