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Reply 860
oops quoted wrong person


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does anyone have a document off all the 6 mark questions that can come up? :smile:
Reply 862
Original post by homefind
Cell organelle are replicated, however number of cells don't increase during interphase


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I was just doing this paper too.im so stupid I forgot the word "interphase" I just put "the cells are in the S phase where DNA replicates" .got 0 -.-
Have you done 6b) that question does not make sense at all


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Reply 863
Original post by chelley2
I was just doing this paper too.im so stupid I forgot the word "interphase" I just put "the cells are in the S phase where DNA replicates" .got 0 -.-
Have you done 6b) that question does not make sense at all


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It's on about how enzymes are specific I think, therefore talk about all that good stuff


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what are the advantages of selective breeding and what definition would u use in the exam?
Reply 865
Original post by gcse2012
So when they are " / / " they still count as homologous chromosomes/ a homologous pair? And when they are / / do they count as two chromosomes as one of the chromosomes will have originally come from a sperm cell and one of the chromosomes will have come from an egg cell?
Also, when they are X X is each chromosome (X) made up of sister chromatids, and one pair of the sister chromatids is from the father and one pair of the sister chromatids from the mother.

Sorry if that it a very confused set of questions but I am very confused by the wording of everything when I try and link it to / and X etc!


Anyone able to help me with the above questions? My questions are in response to havana-affairs post but I don't know how to quote is post as well as mine. Just had a look at the Nelson Thornes book and it says this "In the first division the homologous chromosomes pair up". Does that just mean they align next to each other? It then says "the homologous pairs have separated" does that just mean that the two chromosomes that are homologous chromosomes just split into different cells?
Original post by Lalalamide
what are the advantages of selective breeding and what definition would u use in the exam?


Advantages:-

Improves the species resistance to disease, meaning if more of specie is resistant to disease in for example cows, less number of cows die so increased yield of meat/milk

Which leads on to second advantage

Increased yield means cheaper prices for the meat/milk

3rd advantage) interbreed a certain characteristic meaning the specie causes less damage to each other

4th) food can be produced more efficiently of a consistently high quality which also means reduced prices :smile:
Original post by Jimmy20002012
Thats actually a formula I think, which aqa expected us to kind of work out somehow. Its always 2^ power of how many different chromatids you have I think :wink:


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In fact in maths wise. We use this to determine how many different combinations can be formed for example. How many different combinations. Search this online for it to be explained :smile:


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Original post by chelley2
I was just doing this paper too.im so stupid I forgot the word "interphase" I just put "the cells are in the S phase where DNA replicates" .got 0 -.-
Have you done 6b) that question does not make sense at all


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That strange. Because in one question where they asked during what stage was dna replicated. The examiners accepted both s phase or interphase.


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Reply 869
Original post by Layontheland
That strange. Because in one question where they asked during what stage was dna replicated. The examiners accepted both s phase or interphase.


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I know weird isnt it,I guess choice of key words is important



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Reply 870
Original post by science-oliver
Oooops misread it, although I still don't get it after I've misread it, why when transpiration is not occurring at night is there greater water movement in the trunk than in the branches?




I don't think there is, where does it say that?
Original post by Paulineuh
I'm confused, I always thought that a higher water potential meant it was closer to pure water = 0 so anything lower meant it had proteins/solutes in them so are more negative.

Which exam paper is that?:confused:


Yes me too, that was what I was confused about. Well this question wasn't on any of the papers from the new spec so I'm guessing the old spec then.
Original post by Secret.
I don't think there is, where does it say that?

Okay it doesn't matter :smile:
Can someone explain immunological comparisions of proteins please. :s-smilie: Can't get my head around them it.
why is it that when distance increases, pressure in the aorta decreases? I don't see the link and how does friction reduce pressure?. :s-smilie:
Reply 875
I don't get 1)a) answer on the specimen paper..is there anyone who understands it and can explain?
Reply 876
Original post by Magenta96
why is it that when distance increases, pressure in the aorta decreases? I don't see the link and how does friction reduce pressure?. :s-smilie:


I think it's because the ventricles relax and the muscle in the wall of aorta contracts to narrow the lumen. Not sure about the other bit
Reply 877
Original post by Magenta96
why is it that when distance increases, pressure in the aorta decreases? I don't see the link and how does friction reduce pressure?. :s-smilie:


Actually, it's because of friction
has anybody done the January 2011 paper?
this **** is hard
Original post by lettucesoap
has anybody done the January 2011 paper?
this **** is hard


ugh I know, it's a good thing they're quite generous with the grade boundaries though