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    (Original post by ClarkyC...)
    That's correct
    :party: :party: :party:
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    So annoyed I completely forgot to draw the hydrogen bonds on the DNA molecule!!
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    (Original post by ClarkyC...)
    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
    I thought the answer would be the information they gave us; that grey squirrels stay on the ground more and are less afraid of humans, hence they're more likely to be spotted and reported?

    EDIT: I must say that I'm quite impressed by how much you remember of the exam!
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    (Original post by Vian)
    I thought the answer would be the information they gave us; that grey squirrels stay on the ground more and are less afraid of humans, hence they're more likely to be spotted and reported?
    I thought this too!
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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 though protein was in the question??!! I wrote enzymes...
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    (Original post by Easter Bunny)
    DEM SQUIRRELS! haha, bro i can tell you what i wrote
    For the collagen :-
    1)It is a fibrous protein
    2)It is make up of alpha-C1-C4 Glycosidic Bonds which form long polypeptide chains
    3) it has cross-links made of hydrogen bonds between the fibres
    4) It is strong and flexible
    5) this allows the artery to recoil
    6) It is also insolube , which means it doesn't reduce the water potential of the cells.

    the Selective breeding question: -
    1) Farmers select the plants that have survived and they allow them to reproduce.
    2)They will transfer the Resistive Allele to the offspring
    3)They then breed the offspring over generations, creating a fully resistive species
    4) to improve, and not cause this destruction of plant, they need to increase the gene pool which can be done by bringing in different types of potatoes, or creating cross-programmes where you bring in types of potatoe from all over the world to increase the gene pool.

    HOPE THIS HELPS!!!!!

    But I thought glycosidic bonds are for sugars?! Collagen is a protein. Also, fibrous was in the question? So it win't get a mark....right?
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    What do people think for A/B grade boundaries?
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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

    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
    well, somebody's definitely got an A! Your answers are really good!
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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

    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
    I wrote similar answers to you! Missed out a few but have to see when the results come out!
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    (Original post by Vian)
    I thought the answer would be the information they gave us; that grey squirrels stay on the ground more and are less afraid of humans, hence they're more likely to be spotted and reported?

    EDIT: I must say that I'm quite impressed by how much you remember of the exam!
    Yes they are probably correct but they are my answers I mucked that one up a bit
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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

    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
    OH THANK GOD!!!! My answers are almost identical to this and it makes so much sense to see them written out like that, meltdown over, I was having a total panic i'd done awfully.
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    Same here, when I finished the question I was quite satisfied and thought I got a full mark but now I am really concerned about this.
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    I have a bad feeling i'm looking around 73, 74, and that is excluding your Q6 where I haven't deducted marks. I don't have much hope i'll get my A now
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    This exam was honestly f****ing s**t, worst exam ever.. hopefully low grade boundaries..
    any mark schemes with actual paper?
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    (Original post by theworld)
    This exam was honestly f****ing s**t, worst exam ever.. hopefully low grade boundaries..
    any mark schemes with actual paper?
    It was pretty shocking, its my third time doing it and I'd definitely say it was the worst paper I'd seen..

    Sent from my HTC Desire using Tapatalk 2
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    (Original post by Dan_JR_12)
    The enthalpy change when one mole of a compound is made from its constituent elements under stand conditions, with all elements in their standard states. Why are you asking this on a biology thread?
    Thank you! and I didn't realise I was on the biology thread aha!
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    (Original post by the A* guy)
    Hi everyone sitting the OCR biology F212 exam on the 3rd of June.

    Please use this thread for exam preparation, revision help & support, as well as any chat that refers to the OCR biology AS exams.

    Personally, I am quite nervous about this exam considering the exam length & the amount of information that we need to know for it, in comparison with the first F211 exam.

    What is everyone else doing for revision?
    Does anyone have any ideas of what some of the questions will be?
    Hi, have you got/posted the paper for this exam?
    • Thread Starter
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    (Original post by Saif95)
    Hi, have you got/posted the paper for this exam?
    Sorry no, i don't have this exam.
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    (Original post by Jooost)
    what did you guys put for the phagocyte one?
    wasit B? or C?


    also the process of phagocytosis
    i think i misunderstood teh question
    i spoke briefly aout the enveloping of the phagocyte membrane inward forming a phagosome vacuole and i mentioned the enzymes digesting the pathogen
    but i went onto to talk about antigen presenting cells and the rest of the immune response :c


    any thoughts on the grade boundaries?
    i believe it was the one on the left if i remember because it was undergoing phagocytosis and showed the pathogen being ingest
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    (Original post by Allawy0596)
    I though protein was in the question??!! I wrote enzymes...
    dehydrogenase question was easy, ethanol is a competitive inhibitor
 
 
 
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