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Jimmy20002012
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#781
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#781
(Original post by Magenta96)
I think it's 23 because meiosis produces haploid gamete cells which have half the amount of usual chromosomes and so half of 46 is 23. It also explains that's why when two gametes each fuse together, they form a zygote with the full 46 set of chromosomes.
Is it true you cannot produce sex cells, thus meiosis cannot occur in a mule for example due to them having an odd number of chromosomes, therefore cannot half???


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x-Sophie-x
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#782
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#782
(Original post by Liam2404)
I find unit 2 much easier than unit 1 for some reason, its just the massive hsw that end up pulling my marks down - like that 15 marker on asthma and the 8 marker on the parometer in the jan 2013 paper! Hope because there was quite alot of hsw in the unit 1 paper theres less in this one!
I think the same.

I doubt there'll be less HSW questions though.
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x-Sophie-x
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#783
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#783
(Original post by Jimmy20002012)
Is it true you cannot produce sex cells, thus meiosis cannot occur in a mule for example due to them having an odd number of chromosomes, therefore cannot half???


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Yep. Meiosis does happen though, just not in the correct way.
They have 33 chromosomes I think?
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blackstarz
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#784
Just did the specimen paper and there was a 6 marker on insects gas exchange if anyone was interested i dont know if its just the specimen paper but there seems to be a lot of irrelevant questions and hsw questions. If someones done the specimen can you let me know how difficult you found it compared with the normal papers? Cheers.
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x-Sophie-x
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#785
(Original post by blackstarz)
Just did the specimen paper and there was a 6 marker on insects gas exchange if anyone was interested i dont know if its just the specimen paper but there seems to be a lot of irrelevant questions and hsw questions. If someones done the specimen can you let me know how difficult you found it compared with the normal papers? Cheers.
I've done it. It was ridiculously hard.
Define 'species'. I mean seriously?!
Quite a nice 6 marker though.
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ImAz
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(Original post by x-Sophie-x)
I've done it. It was ridiculously hard.
Define 'species'. I mean seriously?!
Quite a nice 6 marker though.
Species is when organisms can interbreed and produce fertile offspring right?


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x-Sophie-x
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#787
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#787
(Original post by ImAz)
Species is when organisms can interbreed and produce fertile offspring right?


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Yep

But when asked for a definition it simply did not occur to me
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JoeMccarthy
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(Original post by x-Sophie-x)
Yep

But when asked for a definition it simply did not occur to me
I had the same issue when asked to define 'genetic variation'

Funnily enough I got the mark for saying variation in DNA.
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ashabumbleb
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#789
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#789
I have tried to put together a You tube Playlist for this - Just started learning the content for BIOL2 I have 6 days with three hours each day to learn the whole specification fun fun fun!!! The joys of being a private candidate, working full time and being at college full-time in the evenings too - perhaps I have taken a bit too much on

If anyone has any quirky hints and tips (I have 3 copies of each past paper printed ready to be conquered) or pieces of information that I really should know that would be appreciated.

In the meantime the link to my playist for Biol2 is here: http://www.youtube.com/playlist?list...gf3v0EBRv4N0h9

Best of luck everyone x
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Sapphire123
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#790
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#790
(Original post by blackstarz)
Just did the specimen paper and there was a 6 marker on insects gas exchange if anyone was interested i dont know if its just the specimen paper but there seems to be a lot of irrelevant questions and hsw questions. If someones done the specimen can you let me know how difficult you found it compared with the normal papers? Cheers.
Hi, yh i did the specimen paper and i thought the hsw questions were unbelievable, they were simple answers but sometimes the simplest answers don't occur to you in exams! Also have you seen the grade boundaries for unit 2 they are very lenient in regards of getting full ums you can almost on average lose around 10-15 marks which is quite fair
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LiamDaly
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(Original post by LiamDaly)
Also why, I mean WHY is there only cohesion in the apoplastic pathway and only osmosis in the symplastic pathway? PLEASE


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Doess anybody know why? It would be so useful


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Jimmy20002012
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#792
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(Original post by x-Sophie-x)
Yep. Meiosis does happen though, just not in the correct way.
They have 33 chromosomes I think?
Does it? You cant really get half of 33 chromosomes?


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Tee Logan x
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In eukaryotes, much of the nuclear DNA does not code for polypeptides. There are, for example, introns within genes and multiple repeats between genes.

Can someone please explain to me what this means? thank you
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krishio
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#794
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#794
(Original post by x-Sophie-x)
2^3.

Because there are 3 pairs of chromosomes.

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omg you genius!! but i don't get why or how you knew that?
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Jimmy20002012
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(Original post by krishio)
omg you genius!! but i don't get why or how you knew that?
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


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blackstarz
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(Original post by Sapphire123)
Hi, yh i did the specimen paper and i thought the hsw questions were unbelievable, they were simple answers but sometimes the simplest answers don't occur to you in exams! Also have you seen the grade boundaries for unit 2 they are very lenient in regards of getting full ums you can almost on average lose around 10-15 marks which is quite fair
Ye i know what you mean during the exam im clueless as to what to write for some of the hsw questions but when i see the mark scheme im like... it was that easy?
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Secret.
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(Original post by Tee Logan x)
In eukaryotes, much of the nuclear DNA does not code for polypeptides. There are, for example, introns within genes and multiple repeats between genes.

Can someone please explain to me what this means? thank you
I just quickly drew this up so it wont be the best but

they're just regions of DNA that do not code for an amino acid, but you will need to know the difference between introns and multiple repeats
Hope this helped
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Jimmy20002012
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(Original post by Secret.)
I just quickly drew this up so it wont be the best but

they're just regions of DNA that do not code for an amino acid, but you will need to know the difference between introns and multiple repeats
Hope this helped
Do we need to know about exons?


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Neon-Soldier32
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(Original post by Jimmy20002012)
Do we need to know about exons?


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Exons are just pieces of DNA which are coded. Exons = expressed.
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Secret.
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#800
(Original post by Jimmy20002012)
Do we need to know about exons?


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yeah I don't think it's ever been asked before but it's very simple so why not

(it's the coding regions within a gene (in green in that picture), as opposed to the non coding regions introns)
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