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    (Original post by Tania2k9)
    it think he alcohol dehydrogenase question was a little tough and some parts of others can't remember. I am in a big dilemma for this 1 mark question of 'which biological molecule does alcohol dehydrogenase belong to' i said protein am thinking this might be wrong
    I remember in the question it already said that it was a protein, so instead of protein I put enzyme instead as it was relating to the ethanol and DEG substrate. Im about 80% sure about this. Don't worry though most questions were worded badly especially the 7 mark phagocyte question.
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    i know, the phagocyte one is just what happens in the actual process but just continuing of from where they left us
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    (Original post by Missyeln213)
    The squirrels, the alcohol dehydrogenase, the collagen, the potato effing blight, the EIA.

    All the tiny gaps in my knowledge... Exposed! GAH.
    So peeved off at the exam paper and myself right now. Cannot even express it into words. At all.

    Actually, I think all of my exams to date this year have been a series of fails.
    this is exactly how i feel
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    (Original post by Dr Mick)
    I remember in the question it already said that it was a protein, so instead of protein I put enzyme instead as it was relating to the ethanol and DEG substrate. Im about 80% sure about this. Don't worry though most questions were worded badly especially the 7 mark phagocyte question.
    YES THANKYOU I'M GLAD YOU AGREE
    I though the questions were completely misleading
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    (Original post by hassaniqbal99)
    Guys,

    What was the phagocyte in the insert, was it B or C ? :confused:

    And also the question where you had to draw hydrogen bonds between the bases, instead of dotted lines i kept them solid, will it make a difference?
    it was b and c
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    (Original post by Jooost)
    this is exactly how i feel
    Same here! Everything that I didn't want to come up, came up!

    Posted from TSR Mobile
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    It was a decent paper overall, so I think the grade boundaries will be close to 70. I believe I've lost about 20 marks, though come August I'm almost certain I'll have done worse .

    For the infective agent of TB, would Mycobacterium bovis get the mark? For some reason I couldn't remember tuberculosis :facepalm:.

    (Original post by Easter Bunny)
    -The Lysosomes Release Hydrolitic Enzymes that '''BREAK DOWN''' Not 'Digest' the antigen (2)
    I wrote digest

    (Original post by OliverG)
    And for the person who said they thought it was an actual bear, one of my friends did that too (but realised!).
    That's hilarious! It would certainly be the weirdest bear I've ever seen!
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    (Original post by LauraDaniel)
    Same here! Everything that I didn't want to come up, came up!

    Posted from TSR Mobile

    That's exactly what a friend of mine said- she then proceeded to throw her textbook against a wall.

    Seriously though, I swear more than half the marks were allocated to questions on biodiversity or whatnot. And the wording of the long mark written questions were terrible- really vague!
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    (Original post by Vian)
    It was a decent paper overall, so I think the grade boundaries will be close to 70. I believe I've lost about 20 marks, though come August I'm almost certain I'll have done worse .

    For the infective agent of TB, would Mycobacterium bovis get the mark? For some reason I couldn't remember tuberculosis :facepalm:.
    I think you will get the mark for saying 'Mycobacterium bovis'. In the textbook, I'm pretty sure that they say TB can be caused by either. one mark in the bag!

    I think I lost around 20 marks too. Initially it was like 6, and then the more I strolled through tsr the more marks are lost
    If I get an A overall in biology, it'll be a godsent miracle. (And it's meant to be my best subject. Hahahahaha).
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    (Original post by Missyeln213)
    I think you will get the mark for saying 'Mycobacterium bovis'. In the textbook, I'm pretty sure that they say TB can be caused by either. one mark in the bag!
    :woo::woo::woo::woo::woo::woo::woo::woo::woo::woo::woo::woo::woo::woo::woo::woo::woo::woo::woo:

    (Original post by Missyeln213)
    I think I lost around 20 marks too. Initially it was like 6, and then the more I strolled through tsr the more marks are lost
    If I get an A overall in biology, it'll be a godsent miracle. (And it's meant to be my best subject. Hahahahaha).
    I was thinking 17. There's just nothing quite like visiting TSR after an exam!

    I love Biology, but it's my worst subject exam-wise; I just can't stand ecology, the awkward exams and the fact that I suck at memorisation!
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    (Original post by Missyeln213)
    That's exactly what a friend of mine said- she then proceeded to throw her textbook against a wall.

    Seriously though, I swear more than half the marks were allocated to questions on biodiversity or whatnot. And the wording of the long mark written questions were terrible- really vague!
    I think you can know the majority of the knowledge, but the exam paper itself can still throw you off! That's my only problem, so Ill be focusing on exam technique next year.

    Posted from TSR Mobile
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    I spent a while on exam technique, and I had to come to the conclusion that at least one question almosts asks to be quoted from the textbook, but has its own special set of answers seen nowhere else on earth

    I always think i've done really well in that exam when i've done a past paper, and so far i've been the better side of A, albeit borderline, which is infuriating! Watch me get a B or a C now :mad:
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    the guy who said that describing the structure of collagen is saying its insoulbe is wrong thats a property not the structure you need to say primary structure 35% repeating unit glycine. Its has three polypeptide chains wound around eavh other to make a collagen fibril that has hydrogen bonds and the collagen fibrils wound round eavh other to make a collagen fibre which has covalently bonded cross-links. Probably some more stuff i forgot but even saying its a protein with amino acids gets you one mark haha
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    What I got.. I've missed a few marks out because I can't think of them

    Q1
    Name given to sequence of amino acids (1)
    I put polypeptide

    Draw the structure of an amino acid (3)
    H2NCRHCOOH (drawn)

    Why collagen is good for arteries (1)
    I put insoluble, there were many others

    Describe the structure of collagen molecule (6)
    Fibrous
    3 polypeptide chains twist to form triple helix
    Held by hydrogen bonds
    Every third is glycerine making more compact
    Covalent bonds between molecules gives strength
    Then I referred to primary, secondary and tertiary structure

    Difference between haemoglobin and collagen
    Haemoglobin has two alpha glucose and two beta glucose sub units
    Has 4 polypeptide chains
    Globular

    Q2
    Type of biological molecule (1)
    Enzyme

    Why can it catalyse both (3)
    Both have an OH group on the end meaning they have a similar shape to one another, both substrates can bind to the complementary active site of alcohol dehydrogenase and so are able to form ESC by induced fit

    Why high ethanol concentration decreases toxicity (3)
    Ethanol acts as a competitive inhibitor with a similar shape. It forms enzyme inhibitor complexes to the complementary active site. Producing a non toxic product. Low amounts of Ethanol produce ESC which form a toxic product

    Q3
    Infective agent of TB (1)
    Mycobacterium tuberculosis

    How its transmitted (2)
    Airborne droplet (coughing, sneezing etc), I also mentioned the fact that physical contact could spread it

    Describe the data between 2000 and 2008 (3)
    I can't remember which but one group remained the same one went up and one went down
    (Pretty straightforward)

    Why low income have greater incidence (3)
    Homelessness
    Poor health due to not being able to afford health care
    Overcrowding

    Q4.
    Which cells are phagocytes? (1)
    B&C

    Why "secondary"? (1)
    Because primary defence occurs first (I.e skin). If the pathogen is able to get past this then phagocytes are initiated

    Why is it non-specific? (1)
    Does not involve B&T lymphocytes to have receptors complementary to certain antigens

    What happens after pathogen attaches to phagocyte? (7)
    Pathogen attaches to receptors on phagocyte (already stated)
    Pathogen engulfs bacteria by phagocytosis
    Becomes a phagosome and moves to the lysosomes by the cytoskeleton
    Lysosomes engulf the phagosome making it into a phagolysosome
    Release lysins which hydrolyse polymers into monomers
    Antigens move to the surface of the membrane, cytoplasm absorbs all other products

    Q5.

    Calculate SI of Diversity (3)
    I got 0.633 something like that

    Species richness (1)
    Number of species present in a habitat (I also put measured using line transect, qualitative and visual observations)

    Species evenness (1)
    Measures the abundance of individuals in a species (quantitative using quadrants)

    Low SI Index (2)
    Certain species is dominant, unstable habitat, low frequency of useful alleles

    Improve accuracy of sampling (2)
    Use a key to identify species
    Sample more than one area

    Q6.

    Question but I'm unsure what is was

    Why crop yield varies (2)
    Use of fertilisers, different selection pressures, different alleles

    How genetic variation arises (1)
    Random gene mutation

    Selective breeding
    I mentioned that the American plants with the resistant allele need to breed
    Offspring with desired characteristic are the ones that will breed over generation to pass on their gene
    Inbreeding to keep the desired gene in the population
    After many generation frequency of alleles resistant will have increased
    Long term - I think I mentioned use of fertilisers or pesticides, and also isolating some of the species with different selection pressures so if a new disease was to break out then the whole population would not be affected

    Q7.
    define biodiversity (2)
    Number and variety of species in the world, the genes they carry and the habitats in which they live

    Why conservation methods needed for the specific area (2)
    Ecotourism
    Gene pool/genetic diversity (there were many more)

    Suggest why people against culling (1)
    Ethically wrong, we have a moral responsibility to conserve biodiversity

    Why red squirrel population may be higher than counted (2)
    People might not be able to identify red and grey squirrels properly
    Not representative as some areas may have more grey squirrels which were counted

    EIA criteria (3)
    Effects biodiversity
    Harm habitats or endangered species
    Affect and ecosystem or food chain

    Q8.
    Draw dotted lines (3 between C&G), (2 between A&T) (2)

    Components of DNA (2)
    Cytosine
    Nucleotide

    Complete gaps (2)
    Protein? (Might be polypeptide)
    Ribosome

    How RNA would be different to DNA (2)
    RNA is not double stranded
    RNA would have uracil

    Why it is "semi-conservative" (2)
    Old stand and new strand form, template is old strand

    Why complementary base-pairing is important (2)
    Determines primary structure of protein
    Would not form double helix

    Draw in the R1 and R2 (2)
    I did one intermediate DNA then on the next. Intermediate and light DNA

    3 precaution in centrifugation (3)
    Same speed of centrifugation
    Same volume of sugar solution
    Same time for centrifugation

    Q9
    (5)
    genus? (Can't remember)
    Can't remember it was class or order
    phylum
    Kingdom = Animalia
    Domain = Eukaroyta

    Phylogeny (3)
    Study of evolutionary relationships between species, looks at how closely related they are are whether they have common ancestors. Helps taxonomists classify (anatomy, morphology, cytochrome c), also compares there characteristics

    Why water bear was undiscovered (2)
    Too small to be seen
    Technologies were not up to date
    (I got this wrong not really sure about it)

    This is what I put and by no means am I correct but you can compare. Also see what I would roughly get maybe? As I said it would be a guess because I've missed some marks out
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    i thought the paper wasn't extremely hard but it wasn't great either :P
    the first question on collagen threw me, i kinda blanked out and didn't remember much......... :/ but the rest wasn't too bad i answered everything...
    You know the causative agent of TB, did you have to underline it? i didn't but some of my friends did....
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    did the hydrogen bonds have to be drawn as dotted lines?
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    Realised when the invigilator told us to stop writing that I'd made an awful pun in the selective breeding question - I said something about a new disease cropping up :ashamed2::facepalm:

    I thought on the whole it was an alright paper - hoping I've only lost 20 or so marks.

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    (Original post by kited4)
    did the hydrogen bonds have to be drawn as dotted lines?
    I think it would be fine to draw straight lines as long as they were correct
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    (Original post by ClarkyC...)
    I think it would be fine to draw straight lines as long as they were correct
    ahh that's okay - i did 3 lines between the G&Cs and 2 lines between the A&Ts
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    (Original post by kited4)
    ahh that's okay - i did 3 lines between the G&Cs and 2 lines between the A&Ts
    That's correct
 
 
 
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