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    (Original post by ecornwell97)
    anyone got a link to unit 5 practise questions? (that aren't in textbook)
    This thread has lots of PPQ's
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    So what does tropomyosin do, exactly? I'm very unclear, the best I can come up with is "inhibits actin binding sites without an AP triggering Ca2+ release in the sarcoplasm".
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    (Original post by djhodnett)
    oh, i thought the grade boundaries would be higher in this one compared to last years but by peoples responses maybe not?
    I thought last years was so nice! I found this year's considerably harder and more time-stretching (although that said I don't think I did too badly according to the unofficial mark scheme, but I definitely was not happy leaving the exam hall!)
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    Anyone know if we need to know the stuff on p86+87 of the cgp guide?
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    Name:  20150612_153606.jpg
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    can someone mark these for me the importance of protein structure to its function
    Attached Images
     
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    When an action potential arrives, Ca2+ ions are released and move through t tubules to myofibrils. The presence of Ca2+ in high enough concentrations causes a conformational change in the trypsin molecules that lie between the actin molecules and the tropomyosin molecules. The change in the shape of trypsin causes tropomyosin to move, exposing the myosin head binding sites on the actin molecule, allowing the sliding filament mechanism to proceed. Hope that helped)
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    when you have a psych and maths exam the day before biol5.... basically 3 exams in one go!
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    sorry i am a bit late, could someone kindly just repost mentioning what the predicted titles are for this years essay?? Good luck to everyone!!!
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    (Original post by Azurefeline)
    So what does tropomyosin do, exactly? I'm very unclear, the best I can come up with is "inhibits actin binding sites without an AP triggering Ca2+ release in the sarcoplasm".
    During contraction Tropomyosin is removed in order to expose the binding site on the actin filament to form cross-bridges with the myosin head by the release of Ca2+ ions from the sarcoplasmic reticulum in response to the arrival of an action potential at the neuromuscular junction.

    During relaxation Ca2+ are actively reabsorbed back into the Sarcoplasmic reticulum using energy produced from the splitting of ATP to ADP via ATPase.
    This causes the tropomyosin to re-block the binding site on the actin filament because no contraction is taking place.
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    Is anyone else seriously scared for this exam!?
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    (Original post by PurpleJag)
    Is anyone else seriously scared for this exam!?
    Yes, literally terrified, got several exams around it as well, might just do a few past paper now...
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    Me too ive got chem and psych mon and tues before this exam
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    will someone please read over my essay
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    (Original post by nualamurphy5)
    will someone please read over my essay
    Its difficult for another student to mark a bio5 essay because the mark schemes are so bare, its best if you ask a teacher to do it who has a better understanding of how to use the marksheme
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    my teacher is crap does anyone have a good teacher that they could ask to look at it
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    (Original post by foureyes_)
    when you have a psych and maths exam the day before biol5.... basically 3 exams in one go!
    i have 4 content heavy exams next week, my brain is going to explode
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    Has anyone got brief bullet points for DNA technology as i missed all lessons due to hospital appointments and i'm terrified.

    Also,

    any brief bullet points for essays?

    thank you!
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    (Original post by sn4kebiteheart)
    Has anyone got brief bullet points for DNA technology as i missed all lessons due to hospital appointments and i'm terrified.

    Also,

    any brief bullet points for essays?

    thank you!
    https://chemstuff.files.wordpress.co...it_5_notes.pdf
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    Does anybody know if we need to know the differences in protein synthesis between prokaryotes and eukaryotes?
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    Can someone explain resting potential and action potential
 
 
 
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