Hey there! Sign in to join this conversationNew here? Join for free
    Offline

    0
    ReputationRep:
    I've just been through the syllabus for this unit and there are a couple of points i am unsure of, don't know if anyone can help?

    - Explain how the concept of niche accounts for distribution and abundance of organisms in a habitat.
    Is this referring to the fact that organisms that occupy the same niche have to compete and that competition is a biotic factor affecting distribution?

    - Analyse and interpret different types of evidence for global warming and its causes (including records of carbon dioxide levels, temperature records, pollen in peat bogs and dendrochronology) recognising correlations and causal relationships.
    Will questions on this be graph interpretation? Not really sure how much detail we are supposed to know?!


    -Describe the role of micro-organisms in the decomposition of organic matter and the recycling of carbon.

    Thanksss
    Offline

    2
    ReputationRep:

    Dreading this one
    Offline

    0
    ReputationRep:
    Oh also how much are we meant to know about estimating the time of death etc? The specification point on it is very vague and suggests you only need to know the ways it can be determined?!
    Offline

    0
    ReputationRep:
    does anyone have any predictions on whats coming up? especially the big questions
    Offline

    0
    ReputationRep:
    (Original post by Lastminutepanic)
    Oh also how much are we meant to know about estimating the time of death etc? The specification point on it is very vague and suggests you only need to know the ways it can be determined?!
    i think your expected to know it to quite a bit of detail as in the jan 2013 paper there was a 5 mark question on it, saying that , its less likely to come up then
    Offline

    7
    ReputationRep:
    Does anybody have any ideas of what might come up???
    Offline

    1
    ReputationRep:
    (Original post by ADAOBI123)
    mark scheme for 2013 paper please ?
    Here it is...
    Attached Images
  1. File Type: pdf 6BI04_01_rms_20130307.pdf (158.3 KB, 1608 views)
    Offline

    2
    ReputationRep:
    (Original post by SKK94)
    Here it is...

    thank you xxxxxx
    Offline

    1
    ReputationRep:
    What is the difference between allele frequency and gene pool??
    This is what I think:
    - Allele frequency is the number of different alleles in a population
    - Gene pool is the total number of different genes in a population
    Someone please correct me if I am wrong :rolleyes:
    Offline

    0
    ReputationRep:
    (Original post by SKK94)
    What is the difference between allele frequency and gene pool??
    This is what I think:
    - Allele frequency is the number of different alleles in a population
    - Gene pool is the total number of different genes in a population
    Someone please correct me if I am wrong :rolleyes:
    I learnt them as:

    Allele frequency: the number of times (as a percentage or decimal) the same allele appears in a gene pool

    Gene Pool: the number of alleles present in a population at one time
    Offline

    2
    ReputationRep:
    (Original post by SKK94)
    What is the difference between allele frequency and gene pool??
    This is what I think:
    - Allele frequency is the number of different alleles in a population
    - Gene pool is the total number of different genes in a population
    Someone please correct me if I am wrong :rolleyes:

    Total number of alleles in a population - Gene pool

    The proportion of one allele in a population - Allele frequency
    Offline

    0
    ReputationRep:
    Explain how does vaccination bring about the increase in the level of antibodies?
    Offline

    1
    ReputationRep:
    (Original post by amberee)
    I learnt them as:

    Allele frequency: the number of times (as a percentage or decimal) the same allele appears in a gene pool

    Gene Pool: the number of alleles present in a population at one time

    (Original post by yarshad)
    Total number of alleles in a population - Gene pool

    The proportion of one allele in a population - Allele frequency
    Thanks a lot! I think I get it now.

    So when they say allele frequency increases (due to selection pressure), does it mean the proportion of the advantageous allele in the population has increased?
    Offline

    1
    ReputationRep:
    (Original post by bubblegummer)
    Explain how does vaccination bring about the increase in the level of antibodies?
    Vaccinations are a form of artificial active immunity, where the weakened form of a pathogen is injected into the body (the antigens still function though).
    Cells of the immune system can bind to the antigens (provided they have the specific shape on their receptors) and specific antibodies can be made.
    I think in this case, the humoral response occurs( eventually resulting in B memory cells and B effector cells):
    - The B memory cells are able to 'remember' the pathogen - in case of secondary infection
    - The B effector cells become Plasma cells, which then produce the required antibodies.
    Offline

    0
    ReputationRep:
    (Original post by SKK94)
    Thanks a lot! I think I get it now.

    So when they say allele frequency increases (due to selection pressure), does it mean the proportion of the advantageous allele in the population has increased?
    yeah only those with the beneficial allele survive and are able to pass on their genes (which have the beneficial allele) and those that don't can't adapt to the environment so they die out because they are outcompeted

    I hope that's right anyway. One of the topics I need more work on ^__^
    Offline

    1
    ReputationRep:
    (Original post by Lastminutepanic)

    [/B]-Describe the role of micro-organisms in the decomposition of organic matter and the recycling of carbon.

    Thanksss
    -Decomposition by microorganisms
    -These microorganisms respire
    -Releasing carbon dioxide for photosynthesis
    -Methane released in anaerobic condition
    -Methane available as fuel

    Another mark scheme:
    -Carbon/organic compounds digested
    -Digestion provides respiratory substrates
    -Carbon dioxide released from respiration
    -This carbon dioxide is available for photosynthesis
    Offline

    1
    ReputationRep:
    (Original post by Lastminutepanic)
    Oh also how much are we meant to know about estimating the time of death etc? The specification point on it is very vague and suggests you only need to know the ways it can be determined?!
    Just the ways TOD can be determined, i.e, stage of succession, decomposition, body temp, rigor mortis and forensic entomology.
    Offline

    1
    ReputationRep:
    I've seen a question on the Jan 2011 paper, "Describe how the organisms that cause TB are taken up by macrophages", on the mark scheme is mentions the point of 'labelling of bacteria by B lymphocytes/cells', what does this mean?
    Offline

    1
    ReputationRep:
    (Original post by SKK94)
    Vaccinations are a form of artificial passive immunity, where the weakened form of a pathogen is injected into the body (the antigens still function though).
    Cells of the immune system can bind to the antigens (provided they have the specific shape on their receptors) and specific antibodies can be made.
    I think in this case, the humoral response occurs( eventually resulting in B memory cells and B effector cells):
    - The B memory cells are able to 'remember' the pathogen - in case of secondary infection
    - The B effector cells become Plasma cells, which then produce the required antibodies.
    Its actually active artificial immunity, the vaccine can involve either: weakened virus/bacteria (so its harmless); toxin that's been altered into an harmless form; or an actual part of the pathogen containing the antigen (non self) that leads to specific immunity.
    Offline

    1
    ReputationRep:
    (Original post by Satta101)
    I've seen a question on the Jan 2011 paper, "Describe how the organisms that cause TB are taken up by macrophages", on the mark scheme is mentions the point of 'labelling of bacteria by B lymphocytes/cells', what does this mean?
    Stimulated B cells> B effector cells> Plasma cells> antibodies.
    The B cells (indirectly) lead to antibodies being produced, these antibodies bind to specific antigens on the bacteria (labelling them). this labeling, therefore allows macrophages and other phagocytes to identity them more quickly.
 
 
 
  • See more of what you like on The Student Room

    You can personalise what you see on TSR. Tell us a little about yourself to get started.

  • Poll
    What's your favourite Christmas sweets?
  • See more of what you like on The Student Room

    You can personalise what you see on TSR. Tell us a little about yourself to get started.

  • 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.