Join TSR now and get all your revision questions answeredSign up now

OCR Biology F212 Revision [3rd June 2013] (Now Closed) Watch

  • View Poll Results: How did you feel the F212 exam went?
    Awesome
    14
    9.46%
    Good
    50
    33.78%
    Okay
    53
    35.81%
    Bad
    16
    10.81%
    Rubbish
    8
    5.41%
    Not Sure
    7
    4.73%

    Offline

    2
    ReputationRep:


    This could be the answer?
    Offline

    11
    ReputationRep:
    (Original post by Kayess67)
    Where did people draw bands on the centrifuge test tubes? :confused:
    on R1 it was slighlty above the first

    on R2 one band was level with the band on R1 and the other was level with the band in the final test tube

    (I did an algebra thing to prove this somewhere on a previous page)
    Offline

    0
    ReputationRep:
    (Original post by Kayess67)
    Where did people draw bands on the centrifuge test tubes? :confused:
    i did R1 as the same...R2 one the same and second band higher

    for valid i wrote-same suger concentration,same number of spins and rate and volume of dna the same
    Offline

    1
    ReputationRep:
    hey might be a daft question but im just curious...

    for the drawing of the amino acid question i did it in pencil but when we had to draw the H bonds between the bases i did this drawing in pen... will this matter?
    Offline

    14
    ReputationRep:
    (Original post by Kayess67)
    Where did people draw bands on the centrifuge test tubes? :confused:
    First tube I drew a band between n15 and n14

    Second tube same band and one below because the denser n15 was transferred to n14
    Offline

    11
    ReputationRep:
    (Original post by Goldie2912)
    How many marks was it for drawing hydrogen bonds? I totally misread the question and missed that out :'(



    Posted from TSR Mobile
    I think it was 2....but not certain on that one (it was either 1 or 2)
    (Original post by LaughingGas)


    This could be the answer?
    yeh that's right but you don't need the fancy two-tone band thing
    Offline

    12
    ReputationRep:
    (Original post by lahabz2012)
    the very last question was NOT BECAUSE of micrscopess . it was because the water bear has evolved from a common ancestor by natural selection , mutation and u can mention also some environmental factors like competition and predators.....
    I put both so hopefully I get some credit :/
    Offline

    3
    ReputationRep:
    Any and all websites say that a water bear is from the kingdom animalia. I considered protoctista but it didn't look like one so I put animal. Wikipedia says animal


    Posted from TSR Mobile
    Offline

    2
    ReputationRep:
    Bump again if any of you are wondering for what the answer is:


    Found this on google, looks similar
    Offline

    3
    ReputationRep:
    (Original post by krishkmistry)
    Too small and passes through the lymph nodes


    Posted from TSR Mobile
    Also that it has a multilobed nucleus, allows flexibility to move through the pores?
    Offline

    0
    ReputationRep:
    (Original post by ThePremierLeague)
    hey might be a daft question but im just curious...

    for the drawing of the amino acid question i did it in pencil but when we had to draw the H bonds between the bases i did this drawing in pen... will this matter?
    i did it in pen too it doesn't matter but are the lines have to be dotted or normal
    Offline

    0
    ReputationRep:
    (Original post by lahabz2012)
    the very last question was NOT BECAUSE of micrscopess . it was because the water bear has evolved from a common ancestor by natural selection , mutation and u can mention also some environmental factors like competition and predators.....
    LOOL wth did you read :L it cant evolve in 300 years it takes more than that to evolve from ancestors,plus it makes more sense about microscopes that the crap your saying :L
    Offline

    2
    ReputationRep:
    (Original post by g.k.galloway)
    yeh that's right but you don't need the fancy two-tone band thing
    haha I didn't draw them, don't worry, just looked on google to find something similar
    Offline

    12
    ReputationRep:
    (Original post by g.k.galloway)
    When there is an infection macrophages release histamine which makes the capillary walls more permeable/leaky, so they can move easily through the pores out of the blood and into the tissues. I think.
    Macrophages dont as far as Im aware. It's the infected cells.
    Offline

    0
    ReputationRep:
    (Original post by Deziah)
    For the selective breeding one I put that;
    The farmer should choose the crop with resistance to the disease.
    He should then breed them asexually so that they are genetically identical and crop are resistant to the disease - which is ideal for the short term.
    He should also use another method of breeding to increase genetic diversity and variation, so if a new diseases arises in the future not all the crop will die.
    The breeded crop should pass their resistance to the disease onto their offspring, and he should carry this on for generations.
    Eventually all his crop will be resistant to the disease.
    I put for short term the farmer could use pesticides and other chemicals to stop the vectors, which may be insects or just terminate the virus. Don't know if this was right though :/
    Offline

    2
    ReputationRep:
    (Original post by jamesmact)
    Any and all websites say that a water bear is from the kingdom animalia. I considered protoctista but it didn't look like one so I put animal. Wikipedia says animal


    Posted from TSR Mobile
    It said it was a vertebrate so it is animal
    Offline

    1
    ReputationRep:
    (Original post by LaughingGas)
    Bump again if any of you are wondering for what the answer is:


    Found this on google, looks similar
    Omg I completly guessed it.. hope that's the correct answer :')

    Posted from TSR Mobile
    Offline

    1
    ReputationRep:
    (Original post by lahabz2012)
    the very last question was NOT BECAUSE of micrscopess . it was because the water bear has evolved from a common ancestor by natural selection , mutation and u can mention also some environmental factors like competition and predators.....
    I don't understand how people can come on here saying they are 100% of the answer. I believe this was a suggest question, was it not? Either way, there is often more than 2 points that are valid for a 2 mark question.

    I haven't googled the water bear so perhaps you know more about this than me, and having looked around it seems the microscope - in its early stages - has been around since 1595, not to mention the fact the Romans used glass in experiments. That said, unless you are near certain and have some proof to back your case up, I wouldn't scare people so much by saying their answer is 100% wrong.
    Offline

    2
    ReputationRep:
    (Original post by wndms)
    Omg I completly guess it.. hope that's the correct answer :')

    Posted from TSR Mobile
    Same ahaha!
    Offline

    0
    ReputationRep:
    (Original post by MarkProbio)
    I am no examiner and I may be completely wrong but I think you've just completely misquoted what the question asked. It said explain how pathogens are destroyed after the pathogen binds with the receptor on the phagocyte.

    Nowhere was antigen stated. Antigens are presented AFTER the pathogen is destroyed.

    That said, you may well be right in saying that cytotoxic T cells secret hydrogen peroxide and possibly antibodies clumping pathogens together for phagocytosis.

    But I based my response on the phagocyte's mode of action, I think there is enough you can say there to get the six marks (plus the one mark for the correct sequencing).

    1. Pathogen is engulfed by folding of the membrane made possible by the phagocyte's extensive cytoskeleton - endocytosis/phagocytosis.
    2. Pathogen held in a vesicle named a phagosome.
    3. Lysosomes fuse with phagosome.
    4. Secrete digestive enzymes e.g lysins onto pathogen
    5. Pathogen is digested
    6. Antigen presented on plasma membrane
    7. Sequencing of marks 1-6

    Of course I may be wrong and I believe it may have been referring to cytotoxic cells and antibodies as well, but I think you can get at least the majority of the marks by describing phagocytosis correctly.
    Yeah, I wrote about phagocytosis and lysins etc, probably made about 5 points? but thought this wasn't enough so just rambled on about T lymphocytes teehee
 
 
 
Poll
If you won £30,000, which of these would you spend it on?

The Student Room, Get Revising and Marked by Teachers are trading names of The Student Room Group Ltd.

Register Number: 04666380 (England and Wales), VAT No. 806 8067 22 Registered Office: International House, Queens Road, Brighton, BN1 3XE

Quick reply
Reputation gems: You get these gems as you gain rep from other members for making good contributions and giving helpful advice.