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BIOL4 Biology Unit 4 Exam - 13th June 2011 watch

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    (Original post by woods.vanessa)
    I wrote NAD instead of NADP in the very last question :0
    Do you think I'll loose 1 or 2 marks for that or more?!?!
    hiya,

    i think i did exactly the same thing...wrote NADH instead of NADPH
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    (Original post by woods.vanessa)
    I wrote NAD instead of NADP in the very last question :0
    Do you think I'll loose 1 or 2 marks for that or more?!?!
    The examiners will not take away marks. To my knowledge, that's not how the mark schemes work. If you made 6 good points for a 6 mark question, but wrote something additional but silly, you will still get the maximum of 6. If, however, your NAD point was, e.g., your only point, you most probably lost that mark, and would get 0! So that would be worth one mark, but if you made more than X distinct points (4/5/6? I forget) then you'll likely get the maximum anyhoooo.
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    You know the question that said why the breeder got different results to what he expected what did everyone put? I put due to mutations that may have produced more chocolate coloured cats rather than cinamon? Is that right??!?!?
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    (Original post by Superlogon)
    homozygouse was actually 64% anywho.
    Homodominant=64%
    hetero=32%
    homorecessive=4%

    I worked them all out to completly cover every angle possible! :P
    I worked everything out... Got the same as you and made sure it all added up to 1...

    Then wrote down the Heterozygous percentage
    Hoping I'll get one?
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    Rickesh, I knew the answer to this but wrote it in the box for the next question part, by some weird coincidence thinking that was the right answer for the next bit. Which it wasn't. Suffice to say that he expected same number of cinnamon and chocolate cats (as did we, from our punnett square) but he got more chocolate ones (if I remember rightly). This is because whilst our table predicts the frequencies of certain genotypes in offspring of parents with known genotypes, the fusion of gametes is random and therefore does not necessarily reflect the predicted frequencies in a small sample. Now if only I'd written that in the correct box.
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    (Original post by Rickesh)
    You know the question that said why the breeder got different results to what he expected what did everyone put? I put due to mutations that may have produced more chocolate coloured cats rather than cinamon? Is that right??!?!?
    Random selection of gametes during fertilisation. Also mentioned crossing over in meiosis which increases variation
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    For the question on how deforestation and burning of vegetation would affect the concentration of CO2 I put:

    -Plants and trees use CO2 for photosynthesis
    -Their net rate of photosynthesis is greater than the net rate of respiration so plants and trees take in CO2 from the atmosphere
    - by destroying the plants and trees less CO2 is taken in for photosynthesis so there is an increased amount in the atmosphere

    - The carbon compounds in the vegetation is released in the form of CO2 when they are burnt - combustion, so this also increases the amount of CO2 in the atmosphere

    - However, the destruction of plants and trees means that there are fewer niches/habitats
    - therefore species move out or die out
    - there are therefore fewer respiring organisms in the area so less CO2 is released into the atmosphere in that respect
    - However, overall it is likely that the CO2 concentration will have increased in the area.



    Would this get all 6 marks???? what did others put?
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    (Original post by altudios)
    Rickesh, I knew the answer to this but wrote it in the box for the next question part, by some weird coincidence thinking that was the right answer for the next bit. Which it wasn't. Suffice to say that he expected same number of cinnamon and chocolate cats (as did we, from our punnett square) but he got more chocolate ones (if I remember rightly). This is because whilst our table predicts the frequencies of certain genotypes in offspring of parents with known genotypes, the fusion of gametes is random and therefore does not necessarily reflect the predicted frequencies in a small sample. Now if only I'd written that in the correct box.
    Oh no! So what I said was wrong?
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    (Original post by SarahTM)
    Random selection of gametes during fertilisation. Also mentioned crossing over in meiosis which increases variation
    I also put this. I said: predicting the frequency of alleles in the genotype is only an estimate as offspring formed are randomly selected, therefore any of the potential genotypes can be formed.
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    (Original post by woods.vanessa)
    I wrote NAD instead of NADP in the very last question :0
    Do you think I'll loose 1 or 2 marks for that or more?!?!
    You won't lose any for that, both NAD and NADP are equally acceptable.
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    (Original post by SK-mar)
    For the question on how deforestation and burning of vegetation would affect the concentration of CO2 I put:

    -Plants and trees use CO2 for photosynthesis
    -Their net rate of photosynthesis is greater than the net rate of respiration so plants and trees take in CO2 from the atmosphere
    - by destroying the plants and trees less CO2 is taken in for photosynthesis so there is an increased amount in the atmosphere

    - The carbon compounds in the vegetation is released in the form of CO2 when they are burnt - combustion, so this also increases the amount of CO2 in the atmosphere

    - However, the destruction of plants and trees means that there are fewer niches/habitats
    - therefore species move out or die out
    - there are therefore fewer respiring organisms in the area so less CO2 is released into the atmosphere in that respect
    - However, overall it is likely that the CO2 concentration will have increased in the area.



    Would this get all 6 marks???? what did others put?
    It was only 4 :')
    I assume the marks will be for burning releases CO2,
    Trees use CO2 during photosynthesis,
    Less trees = less CO2 removed from the atmosphere
    So more CO2 in the atmosphere

    I think it will be something like that
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    (Original post by Rickesh)
    You know the question that said why the breeder got different results to what he expected what did everyone put? I put due to mutations that may have produced more chocolate coloured cats rather than cinamon? Is that right??!?!?
    i don't think its a mutation. there was a 25% chance that it would be chocolate - it just so happens that chocolate was selected more than expected. it was against the odds but can still happen.
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    (Original post by Rickesh)
    Oh no! So what I said was wrong?
    Well theoretically mutations could cause it, so you might be alright if the mark scheme is forgiving. However, the fact is that most mutations result in something useless happening, and mutation of the allele is not really the primary reason that real offspring don't match the theoretical ones. But you gave an example of a process that can affect offspring genotypes, and you wrote it in the correct box, so you probably got more than me on that one!
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    (Original post by SarahTM)
    It was only 4 :')
    I assume the marks will be for burning releases CO2,
    Trees use CO2 during photosynthesis,
    Less trees = less CO2 removed from the atmosphere
    So more CO2 in the atmosphere

    I think it will be something like that
    im sure it was at least 5 no? or even 6? two 5 markers and the light independent 6 marker?? maybe im wrong haha. so your saying i would have got all marks? thats good then i hope! actually your probably right. one 6 marker, one 5 and one 4 amount to 15. damn i shouldn't have spent so much time on it then haha ....cheers though!
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    (Original post by SK-mar)
    For the question on how deforestation and burning of vegetation would affect the concentration of CO2 I put:

    -Plants and trees use CO2 for photosynthesis
    -Their net rate of photosynthesis is greater than the net rate of respiration so plants and trees take in CO2 from the atmosphere
    - by destroying the plants and trees less CO2 is taken in for photosynthesis so there is an increased amount in the atmosphere

    - The carbon compounds in the vegetation is released in the form of CO2 when they are burnt - combustion, so this also increases the amount of CO2 in the atmosphere

    - However, the destruction of plants and trees means that there are fewer niches/habitats
    - therefore species move out or die out
    - there are therefore fewer respiring organisms in the area so less CO2 is released into the atmosphere in that respect
    - However, overall it is likely that the CO2 concentration will have increased in the area.



    Would this get all 6 marks???? what did others put?
    hey it was only 4 marks..
    and i put..
    cutting trees means reduced removal of carbon dioxide in the atmosphere as plants use carbon dioxide for photosynthesis.
    burning trees releases carbon dioxide in the atmosphere so increases the concentration of the Carbon dioxide.
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    (Original post by SK-mar)
    im sure it was at least 5 no? or even 6? two 5 markers and the light independent 6 marker then?? maybe im wrong haha. so your saying i would have got all marks? thats good then i hope!
    Noo, it was 4, the others were 5 and 6
    Yeah, you put waay enough to get the marks
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    (Original post by SK-mar)
    I also put this. I said: predicting the frequency of alleles in the genotype is only an estimate as offspring formed are randomly selected, therefore any of the potential genotypes can be formed.
    i put it is down to the random fusion of gametes and thats it
    is this right?
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    Is it just me, or did anyone think this paper was easier than January's?

    I think grade boundaries would be about 49???
    Not sure though"/
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    why did the horse use less energy at 9C (march)
    i had no idea :s
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    Completely messed up the very last question but everything else was a gift. Glad I learned Hardy-Weinburg, very glad I'm good with genetics... if I don't improve on my pitiful January grade I give up.
    Thankfully I'll be done after unit 5 and planned to give up anyway. Ha.
 
 
 
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