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

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    (Original post by wndms)
    Last question. Microscope topic is in unit 1. So I thought it made more sense to talk about speciation and evolution because that whole section was about biodiversity.

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    In the specification it required us to know about how how classification has changed due to scientific advancements or something along those lines
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    (Original post by wndms)
    Last question. Microscope topic is in unit 1. So I thought it made more sense to talk about speciation and evolution because that whole section was about biodiversity.

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    Pretty sure evolution and speciation take thousands of years to have an impact, was this a suggest question?


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    Just some quick questions, I'm really nervous so please can you firstly I wrote phagoctyes are non specific because they activate the release of B and T cells which destroy pathogens, they don't do it themselves directly.

    Another question, I put protein for the question, the other answer was ribosome. People are saying its polypeptide but I was just wondering?

    Also, I put phagoctyes are secondary response - I said about memory cells and faster response with more antibodies produced.

    It would make me feel better if someone could confirm the marks for these, just for some peace of mind

    thanks
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    (Original post by Hello...)
    I don't know what people are talking about when they say underlining, has somebody underlined their answer??
    ohh it just says in the book that the binomial Latin name is always written in a style that makes it stand out. In printed text, this italics and when handwritten it's underlined.

    But I think its okay if you didn't.
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    (Original post by xKaylax)
    Is there an unofficial mark scheme for this? I didn't think it was too bad but a lot of my friends thought it was really hard so hopefully grade boundaries won't be too high
    Go back a few pages and its impossible to miss xD
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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 may have made some mistakes thinking back. I put The primary structure for the first question. For the infective agent of TB I only put mycobacterium, for the bonding question I put 3 hydrogen bonds between C and G and two between A and T, but I drew 3 straight lines instead of dotted (however I did label the bond as hydrogen bonding) would I still get the mark?) and lastly the phagocyte cell, I put C and B but then crossed out B
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    (Original post by Liberty.)
    I was sosososo lucky that I looked over it just before entering the exam.
    I suspect lots of brain farts tomorrow, in Chemistryy!
    Oh my goodness- tell me about it- so under prepared for chemistry!!!!!


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    (Original post by Minz)
    3 precautions in centrifugation
    -Same volume of DNA
    -Same volume of sugar solution
    -Same time for centrifugation

    Is the first point correct? same volume of DNA? Wouldn't it determine how much is spun out if it is more or less?



    I reckon grade boundaries will be about 73 for an A. Its like ocr wants everyone to suffer
    :unimpressed:
    a agree, although the grade boundaries may be 72 or 71 ish
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    (Original post by ClarkyC...)
    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

    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 ESCORT 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
    oh wow..as if you remembered all that :O but that seems correct most of it! Well done!
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    That should not say ESCORT it should be ESC(enzyme substrate complex)
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    (Original post by GirlWithADream)
    What did everyone write for the question on EIA?
    I wrote that they assess:
    -Whether the area is habitat to an endangered species
    -The rarity of the habitat
    -To what extent the new development will affect the biodiversity of the area

    How likely is it that I get the 3 marks?
    Very likely, I hope, since I wrote the same thing
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    (Original post by ClarkyC...)
    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

    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
    There was also a part question in Q1 about the differences between haemoglobin and collagen.
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    (Original post by ellie2996)
    Just some quick questions, I'm really nervous so please can you firstly I wrote phagoctyes are non specific because they activate the release of B and T cells which destroy pathogens, they don't do it themselves directly.

    Another question, I put protein for the question, the other answer was ribosome. People are saying its polypeptide but I was just wondering?

    Also, I put phagoctyes are secondary response - I said about memory cells and faster response with more antibodies produced.

    It would make me feel better if someone could confirm the marks for these, just for some peace of mind

    thanks
    Protein or polypeptide will get you the mark.
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    my head blanked out completely for question 1 :'( got so worried and tensed that didnt even remember anything on collagen :/
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    i spelt mycobacterium as micobacterium, would i still get the mark?
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    (Original post by BioGeek)


    Draw Hydrogen bonds between polynucleotides (2)
    3 between C and G
    2 between A and


    Were cytosine and Guanine at the top?

    I drew 3 hydrogen bonds for the top one...

    completely forgot what was a purine/ pyrimidine :O
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    On previous past papers, the grade needed for an A is typically mid-late 60's with the highest being 73...
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    (Original post by ellie2996)
    Just some quick questions, I'm really nervous so please can you firstly I wrote phagoctyes are non specific because they activate the release of B and T cells which destroy pathogens, they don't do it themselves directly.

    Another question, I put protein for the question, the other answer was ribosome. People are saying its polypeptide but I was just wondering?

    Also, I put phagoctyes are secondary response - I said about memory cells and faster response with more antibodies produced.

    It would make me feel better if someone could confirm the marks for these, just for some peace of mind

    thanks
    Hi Ellie, first of all protein and polypeptides are the same thing so you'd get the mark.

    Phagocytes are secondary defenses, not in the secondary immune response. So nothing to do with antibodies I'm afraid.

    It's non specific as it can act on any antigen as opposed to only one like lymphocytes.

    Hope I helped.
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    (Original post by MarkProbio)
    Hi Ellie, first of all protein and polypeptides are the same thing so you'd get the mark.

    Phagocytes are secondary defenses, not in the secondary immune response. So nothing to do with antibodies I'm afraid.

    It's non specific as it can act on any antigen as opposed to only one like lymphocytes.

    Hope I helped.
    Thank You !!! xxx
 
 
 
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