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OCR A2 Biology F215 Monday 13th June EXAM QUESTION ERROR?

Discussion in 'Science' started by dhoskyns1, Jun 18, 2011.

  1. I would be very grateful to hear anyone's opinion on whether or not you agree with me that OCR have made an error in question 7 of the F215 paper on monday 13th.
    It is a Hardy Weinberg calculation and I am convinced they have made a mistake by mixing up the dominant and recessive forms in the info given for Q7 part c(ii). The info at the very start of question 7 contradicts the info at the start of part c. This could make it very confusing to students when calculating the allele frequencies.
    If anyone gets the chance to check it out I would be grateful to hear what you think.
     
  2. I would be very grateful to hear anyone's opinion on whether or not you agree with me that OCR have made an error in question 7 of the F215 paper on monday 13th.
    It is a Hardy Weinberg calculation and I am convinced they have made a mistake by mixing up the dominant and recessive forms in the info given for Q7 part c(ii). The info at the very start of question 7 contradicts the info at the start of part c. This could make it very confusing to students when calculating the allele frequencies.
    If anyone gets the chance to check it out I would be grateful to hear what you think.
     
  3. There's no error, although at first glance it appears to be wrong.
    Although we would usually expect the most common phenotype to be the dominant, this is not always the case when there is another factor involved - maybe the melanic form gets eaten more frequently or heats up too much so has a much lower survival rate. If the melanic form is created by a mutation which is dominant to the red form, but is selected against, then the table and info make sense. (Think of the odd data that can show up with peppered moths when there's selection involved as well as genetics)
    Also, they were carefull not to have the data in the table in ratios we would normally expect from monohybrid crosses (3:1) etc.
    Part c) clearly states which is the dominant and even expands on this to say that the red is homozygous recessive for bb.
    The question is not only testing the use of Hardy-Weinberg, but the students' ability to use <u>all</u> the data/info provided.
    Hope this helps.

     

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