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OCR F211/F212 AS Biology Retake 2016 watch

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    Q1
    a) C, O, OH
    b) OH and H inverted around the Carbon
    c) 1,4 Gylcosidic Bond, Maltose
    d) Compact, Branched so glucose easily broken off, Animals require lots of glucose due to high levels of activity

    Q2
    a) beta pleated sheet
    b) Hydrogen bonds
    c) tertiary structure
    d) subunits
    e) quaternary

    Anyone else fancy continuing? Cheers
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    It was called orlistat, I think it's used as a weight loss supplement.


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    And it isn't lactose. That's alpha glucose and galactose. This was two alpha glucose, so maltose.


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    Q3
    a) Active Artificial
    b) .....don't remember
    c) Viral RNA code changes, amino acid sequence changes, different tertiary structure

    Not sure what other questions

    Q4

    a) Biuret test, Blue -> Lilac
    b) 1.4
    c) 0.35g
    d) Use a better colorimeter, less gaps between enzyme concentrations
    e) Use no enzyme, just water and biuret

    Not sure on last two
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    (Original post by GetOverHere)
    And it isn't lactose. That's alpha glucose and galactose. This was two alpha glucose, so maltose.


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    Changed it wrote maltose in the exam thankfully
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    (Original post by Beckyg19)
    I put species richness and species eveness.. Did anyone else?
    Me too dw
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    I think the cofactor question was next
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    (Original post by Bgxx)
    Someone please make a mark scheme
    Has anyone made a unofficial mark scheme?
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    out of rating scale of 10. how did everyone find it? 10 being hardest exam ever done
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    (Original post by Rajan_S97)
    Q3
    a) Active Artificial
    b) .....don't remember
    c) Viral RNA code changes, amino acid sequence changes, different tertiary structure

    Not sure what other questions

    Q4

    a) Biuret test, Blue -> Lilac
    b) 1.4
    c) 0.35g
    d) Use a better colorimeter, less gaps between enzyme concentrations
    e) Use no enzyme, just water and biuret

    Not sure on last two
    For Q4b) i said he should do a curve instead of doing dot-to-dot, and then find the enzyme concentration.
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    (Original post by RescueToast)
    For Q4b) i said he should do a curve instead of doing dot-to-dot, and then find the enzyme concentration.
    I dont think it would have made a difference? Surely dot to dot more accurate right ?
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    (Original post by Redman789)
    I dont think it would have made a difference? Surely dot to dot more accurate right ?
    A curve is a better way to represent that data, but you'd have still gotten the same answer. I put measuring 1.5 mg cm-3, using smaller intervals (e.g. 0.25mgcm-3) and I'm sure I put something else too but I can remember.


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    The question asked specifically how the method could be improved, not the data presentation. Oh yeah I remember, I said to do repeats haha.


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    Repeats ? I think wrote that .... hopefully i did ! Maybe a larger range perhaps i dunno
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    (Original post by Rajan_S97)
    Q3
    a) Active Artificial
    b) .....don't remember
    c) Viral RNA code changes, amino acid sequence changes, different tertiary structure

    Not sure what other questions

    Q4

    a) Biuret test, Blue -> Lilac
    b) 1.4
    c) 0.35g
    d) Use a better colorimeter, less gaps between enzyme concentrations
    e) Use no enzyme, just water and biuret

    Not sure on last two
    Q5 - explain the effects of tar on the lungs

    Tar settles on lining of airways and alveoli increasing diffusion distance for oxygen entering blood and CO2 leaving blood
    Chemicals in tar can cause allergic reaction causing airways to contract - reduced lumen so restricts airflow
    Tar damages cilia therefore they are unable to move mucus
    Tar stimulates goblet cells and mucus secreting glands to secrete more mucus
    Bacteria collect in mucus - smoker is more susceptible to infection
    Smokers cough damages lining of airways replacing it with scar tissue - this is less flexible and thicker
    Presence of bacteria in mucus causes inflammation - chronic bronchitis
    Phagocytes attempt to fight pathogenic material - they release an enzyme elastase which reduces the elasticity of airways - emphysema
    Reduction of elasticity can cause alveoli to burst as pressure increases due to alveoli walls not recoiling and expelling all air out
    Chronic pulmonary obstructive disease is a combination of chronic bronchitis, emphysema and asthma
    Tar contains carcinogens such as benzopyrene - can cause mutations in the DNA and cells divide uncontrollably causing lung cancer


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    (Original post by Redman789)
    Repeats ? I think wrote that .... hopefully i did ! Maybe a larger range perhaps i dunno
    Yeah, you could test it a few times and then calculate the mean absorbance to reduce random error and eliminate anomalous results. To be honest I don't think a larger range would help, seeing as the absorbance measurement was only 1.4 whilst the absorbance at 2.00mgcm-3 was higher than that I think. It's like if you're measuring an insect, you don't need a meter stick because the insect is so small anyway.


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    (Original post by Anymorefor123)
    I doubt you'd have to state the number hence it was only 1 mark and the q just asked for the bond


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    yeah pretty sure it was between alpha glucose sub units which could have either 1-4 or 1-6 so i think just glycosidic would be fine. If not, then i doubt most people got it anyway.
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    What did you guys write for the question about how the students got the (0.0, 0.0) point in the graph on the enzyme experiment?
    I was so confused. I wrote about how they'd have to calibrate the colorimeter using pure water/ white paper, or the students could form a solution containing 0% enzyme conc
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    If you get like an A at AS overall and get A*s in A2 exams would you end up with an A* overall?
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    I put subunits in the fill in the blank space first then crossed it out and put chains:ashamed2::ashamed2::ashamed2: Would that not be right too, alpha and beta chains?
 
 
 
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