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    (Original post by ibysaiyan)
    Yea same boat.I got a D too but anyways this time My plan is to ace it.Last time I completely skimmed through genetics and left awful lot on animal behavior LOL.
    Not happening now.So when are you planning to revise? I have 3 more exams before this one.I have completely finished variation/genetics.I am good with biotech,that shouldn't be a worry.
    At the moment I've memorised my notes so just saying them over and over again to myself at the moment so nothing serious as I have one exam before it and that's this Friday, so once that's done, I'll have 12 days of crazy F215 revision
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    (Original post by mathsclown)
    At the moment I've memorised my notes so just saying them over and over again to myself at the moment so nothing serious as I have one exam before it and that's this Friday, so once that's done, I'll have 12 days of crazy F215 revision
    Good good.Perhaps we could help each other out.
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    (Original post by ibysaiyan)
    Good good.Perhaps we could help each other out.
    Definetly I'll be on here for whole of next week and the week of the exam, so we can share some knowledge!
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    (Original post by mathsclown)
    Definetly I'll be on here for whole of next week and the week of the exam, so we can share some knowledge!
    Cool.
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    http://www.execulink.com/~ekimmel/drag_gr11/sexlink.htm

    Whats the answer for the last two questions about offspring?

    Nevermind :P just realised why it was coming up wrong silly percentage sign
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    (Original post by aimz08)
    http://www.execulink.com/~ekimmel/drag_gr11/sexlink.htm

    Whats the answer for the last two questions about offspring?

    Nevermind :P just realised why it was coming up wrong silly percentage sign
    Did you get my previous quote to you ?
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    (Original post by ibysaiyan)
    Ouch not much time left damn.So far I have just completed variation/and stuff related to genetics. Gr...

    Alrighty lemme recall... hmm
    Biological def. of species: A group of individual organisms that share same morphology,physiology,anatomy and are able to breed with each other to produce fertile offspring.

    In biological species concept two criteria are needed:
    1) It applies to sexually produced organisms.
    2)Species extinct,produced asexually/fossils don't get categorized.
    Hence the disadvantage over this concept is that it limits the no. of species(less diversity)/ignores organisms produced asexually.

    Evolutionary (phylogenetic) concept deals with how close do two organisms are to each other i.e how back do they share common ancestry.If there are signs of having common linkage then these are classified as other species without even knowing whether there is a reproductive isolation btw. the two species or not.

    for example: A duck living in region X and other one living in region Y,have different colour ,nothing is known about their isolation = classified separately.

    The advantage of this method is that it widens the no. of species and includes what the above concept excluded.The only dis-advantage is that it's not reliable since any person/organisation could come up wit their own no. of species based on their said assumptions.

    The book which I have by Mary jones includes only A.I of cow (

    Artificial Insemination:
    A.I is done to increase the rate of offspring's compared to the wild population.
    A chosen bull's semen is collected.In the wild this would only impregnate a cow but in A.I a large no. of cows are impregnated with the semen.

    The bull goes through progeny testing.To check whether it has the suitable traits or not.If it's female offspring's show the desired traits,farmers use it's sample for the breeding programme.All this takes time hence why semen is stored/frozen for a longer period (2 years approx).In during which the calf matures and so forth.

    Embryo transplantation:
    A chosen cow with the desired trait is a. inseminated with semen.She's fed with different hormones for her to super ovulate.At the oviducts embryo (fertilizes).In the uterus it's washed out of the cow/ Now it could either be further divided into two embryo + or transfered into surrogate mother/s.
    The surrogate mother needs to be fed with same hormones for her uterus to carry.
    Surrogate mother is of low value compared to the parent cow.
    Yes I did thanks Helps...
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    Quick meiosis question...making me confused.

    Homologous pair-does this refer to the 2 chromatids conected by the one centromere ie: 'X' or does it refer to 2 of the same chromosome ie: 'XX', if so than it can also be as 'II' (chromosome not replicated yet...)

    bivalents: refers to a pair of chromosome temporarily united. Does this mean 'X' or 'XX'?

    Are bivalents the same as a homologous pair or not?
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    (Original post by aimz08)
    Quick meiosis question...making me confused.

    Homologous pair-does this refer to the 2 chromatids conected by the one centromere ie: 'X' or does it refer to 2 of the same chromosome ie: 'XX', if so than it can also be as 'II' (chromosome not replicated yet...)

    bivalents: refers to a pair of chromosome temporarily united. Does this mean 'X' or 'XX'?

    Are bivalents the same as a homologous pair or not?
    Four Chromatids or tetrads.
    Before meiosis dna replication occurs in which ,say for example l becomes ll.
    Since humans have two sets of each chromosome you end up with the homologous pair consisting of ll-ll.
    Bivalents is when ll or in your example XX join during prophase one.Yep bivalents are same as homologous pairs.
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    (Original post by ibysaiyan)
    Four Chromatids or tetrads.
    Before meiosis dna replication occurs in which ,say for example l becomes ll.
    Since humans have two sets of each chromosome you end up with the homologous pair consisting of ll-ll.
    Bivalents is when ll or in your example XX join during prophase one.Yep bivalents are same as homologous pairs.
    Hey remember me?

    I got 90/150 which was terrible, so I am resitting this module only, although I dont see the point as I cant go up. I would need like 131/150 to go up a grade and I haven't started proper revision yet! :eek:

    But I do have an unconditional offer so far plus Im looking at school leaver schemes which need a maximum of 300 UCAS points anyways, which I have.

    How are you feeling for this exam?
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    (Original post by Chunkeymonkey62)
    Hey remember me?

    I got 90/150 which was terrible, so I am resitting this module only, although I dont see the point as I cant go up. I would need like 131/150 to go up a grade and I haven't started proper revision yet! :eek:

    But I do have an unconditional offer so far plus Im looking at school leaver schemes which need a maximum of 300 UCAS points anyways, which I have.

    How are you feeling for this exam?
    Well I got a D on it last time.I am sitting this module only and so I am aiming to achieve 100% on this.So far I have gone through genetics,variation.Tonight I will finish vegetative propagation,and biotech stuff. =]
    Twelve days left =P
    That's great =]
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    (Original post by ibysaiyan)
    Well I got a D on it last time.I am sitting this module only and so I am aiming to achieve 100% on this.So far I have gone through genetics,variation.Tonight I will finish vegetative propagation,and biotech stuff. =]
    Twelve days left =P
    That's great =]
    Ah. I somehow cant keep concentrating. I had planned on doing 6-9 pages today but only completed one

    I remember someone put some notes up which are answers to each syallabus point which Im hoping will get me through the pages quicker. Are you retaking any other subjects?
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    (Original post by Chunkeymonkey62)
    Ah. I somehow cant keep concentrating. I had planned on doing 6-9 pages today but only completed one

    I remember someone put some notes up which are answers to each syallabus point which Im hoping will get me through the pages quicker. Are you retaking any other subjects?
    A module of physics and couple for maths.
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    I'm also resitting this exam, got a C in it, but A's in all my other Bio modules, so need to try and get an A in this exam! My main problem is lack of practice questions, I can't seem to find any papers, apart from the specimen one and the one that I sat in June. Does anyone have access to questions, particullarly ones regarding genetics and the whole genetic diagrams/epistasis/chi-squared test crap etc? Would help a million! The first topic is the hardest and the rest are ok, just have to crack genetics and fingers-crossed i'll be fine

    X
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    (Original post by twinkl3)
    I'm also resitting this exam, got a C in it, but A's in all my other Bio modules, so need to try and get an A in this exam! My main problem is lack of practice questions, I can't seem to find any papers, apart from the specimen one and the one that I sat in June. Does anyone have access to questions, particullarly ones regarding genetics and the whole genetic diagrams/epistasis/chi-squared test crap etc? Would help a million! The first topic is the hardest and the rest are ok, just have to crack genetics and fingers-crossed i'll be fine

    X
    Yep.That's why I cracked on genetics first
    to do them you'll have to use old syllabus past papers: 2804/04= ]]]]]]]
    Anything bothering with genetics? Post it here...


    I got all A's in my previous module too 95% in 214 but a D on f215.Lack of practice =]
    11 days to go.. I will finish cloning/biotech tonight =]
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    9 days left Grrr....
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    Question anyone?
    If chi squared value is larger than the critical value, how can this be explained genetically?
    also, can anyone explain genetic drift/founder effect?
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    (Original post by hazu121)
    Question anyone?
    If chi squared value is larger than the critical value, how can this be explained genetically?
    also, can anyone explain genetic drift/founder effect?
    Yay AT LONG LAST SOMEONE POSTED HERE with some INTEREST... Right from what I can recall on chi square is that say if the value which we get is less than the critical value of 0.05 probability then it's safe to assume that null hypothesis is valid i.e we expect these difference to occur and are not by chance but if the value is greater than the critical value we reject null hypothesis,we need to reconsider our experiment.

    Genetic drift is the random/change shift in the number(set) of alleles of a population (definition for gene pool).The criteria for genetic drift to occur are:
    *No selection pressure/or low pressure.
    *Occurs RANDOMLY WITH no connection to natural selection
    *Anytime and in particular to small populations
    *More often in island places.
    How it all happens?
    basically you get few individuals in a small population who overtime by chance happen to survive better and hence reproduce on the contrast others who can't cope die.You end up with a chance of alleles in this population resulting in the change of charactersics.These alleles become dominant and hence shift the previous gene pool.
    =]]]]

    Founder effect is a special case of Genetic drift but in the OCR spec we don't need to know that.If you have any more follow on questions to this post of mine or anything to do with genetics/variation ,please quote me back.
    Good night it's almost 8 am xD

    EDIT: I just re read your post on chi square: the only genetic explanation to that is hm... I think mutation could be the reason for the differences OR polygenic inheritance to cause continuous variation =]
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    Pheewww my maths exams are other now, and had a day off from revision yesterday, so today going to go other my notes and post up the stuff I know about cellluar control and variation (would do genetics but it's kinda like maths, if you practise it, you'll get it )

    BTW Does anyone have a copy of the June paper? Thanks.
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    (Original post by Chunkeymonkey62)
    I remember someone put some notes up which are answers to each syallabus point which Im hoping will get me through the pages quicker.
    Looking for this? I went through them, they are great, but if you are going to go through them make sure you've got the text book handy, there are a few points missing, but other than that, they are a great set of notes
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  1. File Type: pdff215.pdf (249.9 KB, 159 views)
 
 
 
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