(Original post by aj_slate)
... Another thing, can anybody help with recessive and dominant epistasis?
Recessive epistasis is where homozygous recessive at the first locus masks the expression of alleles at the second allele. So if A/a was the first locus, and B/b was the second locus, then aaBb/aaBB/aabb would mean that only the aa alleles would be expressed. The ratio for this is 94
Dominant epistasis is where a dominant allele(s) at the first locus masks the expression of alleles at the second allele. So if C/c at the first locus and D/d was the second locus, then CcDd/CcDD/Ccdd/CCDd/CCDD/CCdd would mean that only the C allele would be expressed. The ratio for this is 121 or 13:3
Thank you! I understood dominant and recessive epistasis, but the exam was horrible, there was nothing on anything I knew well like protein synthesis or plasmid, but thanks again, just got to hope I did well enough.
I hope you take the time to read the following as I have dedicated time to writing this, whereas I could be using this time to revise for an exam in the forthcoming week. I have been in education all my life in the United Kingdom and have been privileged to have received education at the expense of others. I am in the final year of college and yesterday undertook an exam written by the OCR exam board. The exam was the Biology F215 sat on the 15th June 2012 at 9.a.m I feel that I need to express my complete anger and disillusionment at the paper which I sat for a number of reasons.
This is not the first time I, or others for that matter have had problems with your papers that you have written up. An exam board which publishes papers with spelling errors justifies this. Last year, as you are fully aware, there were a number of complaints due to the F215 exam set. My elder sister in A2 at the time had an offer from Birmingham University for Medicine which required AAB, and missed an A in Biology by 5 UMS due to the paper set. I felt the paper set this year was just as bad as last years, if not worse, due to the numerous suggest questions and some absolute ludicrous questions.I feel cheated due to the fact that we are expected to revise 3 different modules for the exam, and yet the paper is predominantly based on subjective suggest questions? I have an offer for Medicine form the Kings College London and I am fully aware that missing the A grade in Biology is now a real possibility due to the paper you set. I feel the content did not test us on what we were asked to learn, and although I acknowledge that the exam tests students on synoptic and unifying concepts, there is a limit as to how many suggest questions you can ask.
Another major problem I have is the fact that the exam board re-used a whole question from one of the earlier legacy papers. I was absolutely shocked to find this exact question was in an earlier paper, and had not been modified in the slightest. I understand exam boards tend to re-use old specification papers, however copying a whole question is unacceptable, and what has infuriated me is the fact that these paper materials were not available to our college whereas they were to the other grammar sixth forms in Birmingham, only hours prior to the exam. I have never experienced this with AQA,Edexcel,WJEC or any other exam board that I have undertaken a paper with. The sheer laziness of the those who produced this paper has not only angered me, but the teachers and students who study A-level Biology at my college, as well as family and friends alike. The inconsistency with the questions asked in the papers you set amazes me as the Jan 2012 F214 paper was a standard paper where no one had any real complaints, however it is this paper that seems to consistently draw up controversy. Some suggest that you have a hidden agenda as you do not want people to gain places in Universities across the United Kingdom, I strongly disagree with this, however I do not want my younger brother or sister to go through this again, and feel the heartache that my sister did last year due to any of your papers you set.
I hope that you take the points I have made into consideration, and that they do result in action, whether it be a statement and I am expecting a significant drop in the grade boundaries for this paper. I will not hide my immense frustration and will do all that is in my power to get my voice heard, whether it costs me traveling half way across the country. Thank you for taking the time to read my views, and wish that these problems will be addressed in the future.
I'm really struggling with genome sequencing and the steps in it as I've read different in each text book and find it a confusing concept.
Could somebody please list the steps of genome sequencing for me,
And tell me why electrophoresis is needed it it?
And whether you compare overlapping regions or use the automatic fluorescent terminator base process as the final step? Thanks