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AQA BIOL2 ~ 21 May 2012 ~ AS Biology

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Original post by Jack_Smith
what is the difference between conservative and semi-conservative model?


simply speaking, constervative model produces 2 DNA molecules, one with the original bases, the other with new ones

semi conservative mixes the 2 strands, so 1 DNA molecule has 1 strand of the new bases and 1 strand of the old bases
Reply 1981
Avatar for hazelw
hazelw
Original post by dongonaeatu
George, if she struggles with that question, she is on course for a U in the exam.


okay mate seriously calm down, i misread the question, not everyone is a wiz like you, you have no right to say that a day before the exam
I just did Jun '10 and I got 66/85, that's 126 UMS and would have given me an overall B at AS :O. I'd be ecstatic if I could do this tomorrow :')
(edited 11 years ago)
Original post by dongonaeatu
What grade did you get in unit 1?


B, why?
Reply 1984
Avatar for Livvy99
Livvy99
Guys please help, is concentration gradient and diffusion gradient the same thing? i'm so confused... :frown:
Original post by rturnbull94
I just did Jun '10 and I got 66/88, that's 126 UMS and would have given me an overall B at AS :O. I'd be ecstatic if I could do this tomorrow :')


Well done. Fingers crossed for us all tomorrow!
Original post by unbelievable
just realised my teacher skipped a chapter and trying to do last minute revsion anyoe care to help with chapter 10


i have my teachers powerpoint presentations on the chapter i could forward the contents of chapter 10 to you if you think that would be helpful?
Original post by pepeeglesfield
good luck for tomorrow everyone...i'm strangely excited :biggrin:


Yeah.... That's strange :P
Reply 1988
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rommy123
Original post by GemachtFurDamon
the question on hybirdisation ?

well hybirdisation is when a strand of dna is heated untill it is seperated(as all hydrogen bonds joining the helix have broken) and mixed in with a strand of different dna. the closer the dna of the species are related the more base pairings there will be. these parings with the dna from the other species is called the hybirdisation. so the higher the percentage of hybirdisation the more closer the species are linked.

in this case it would be Grus americana and Grus monachus as they are two different species with the highest percentage of hybirdisation.

REMEMBER HYBIRDISATION ONLY OCCURS BETWEEN TWO DIFFERENT SETS OF DNA.

i hope this is helpful and is the correct question.


Thanks, Understand it now :biggrin:
Original post by Starlight94
B, why?


I got a B too
Original post by idontquitelikecake
Well done. Fingers crossed for us all tomorrow!


:crossedf: Indeed, I wish everyone the best of luck - let's hope the paper isn't too difficult :smile:
Anyone up to explain the semi-conservative model experiment..think it might come up tomorrow and i dont get it :/
Original post by GemachtFurDamon
i have my teachers powerpoint presentations on the chapter i could forward the contents of chapter 10 to you if you think that would be helpful?


that would be amazig thank you
Original post by Jack_Smith
Anyone up to explain the semi-conservative model experiment..think it might come up tomorrow and i dont get it :/


Semi-conservative is basically where when a DNA molecule splits and forms the new strand, that the new molecule has half the original strand with a new strand :smile:
Reply 1994
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Rayquaza
Original post by GemachtFurDamon
if you have chemistry you could do biochem biomed or something along those lines.

you can do biomed in some unis without chemistry but you have to research. also you could do a biology degree or a degree in genetics. there is a lot of choice just research what the universities you want to apply for offer. :smile:


Yeah, I'm studying chemistry. Thanks, I'll look them up :smile:
Original post by rommy123
Thanks, Understand it now :biggrin:


oh thanks :P
Original post by dongonaeatu
One person does mark an entire physics paper. Dont be idiotic.


No, they don't. It's part of standardisation.

I'm stupid though, because it's not as though I was ill when I took BIOL1 but still got 100 UMS (illness being your excuse for not getting an A, I believe? Man up!).
Original post by Jack_Smith
Anyone up to explain the semi-conservative model experiment..think it might come up tomorrow and i dont get it :/


The Semi-Conservative Model experiment is when we separate a Strand of DNA into its 2 Polynucleotide chains; which is done using a special Enzyme called DNA Helicase. With these 2 strands of Nucleotides; we can mix them with free Nucleotides; as they act as "Templates" as each Organic Base only had one other complementary base that it can join to.

After mixing the two strands with free nucleotides, we use another enzyme called DNA Polymerase; which is used to connect the free nucleotides that are connected to the polynucleotide chain and bond them together to create the other Polynucleotide chain.

I'm sorry if its a bit confusing :P
Original post by unbelievable
that would be amazig thank you


hope it helps you there's some activities in it too i suggest you really try doing them how did your teacher manage to miss out a whole chapter and this chapter almost always comes in the exam. good luck :smile:
chapter 10.pptx1001.1KB
Original post by rturnbull94
Semi-conservative is basically where when a DNA molecule splits and forms the new strand, that the new molecule has half the original strand with a new strand :smile:


i mean the evidence!

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