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A2 Biology OCR June 2015 Revision Thread

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thought the paper was decent ... did not like the last question though, on nicotine. Didn't finish .. so I've missed a 3 marker.literally begging for low grade boundaries after f214
Original post by alexandralilley
I think the exam was better than last year's one. They could have made it much worse
What did people put for the one about the significance of plants having more than one set of chromosomes to create new species?


i agree! what the hell is that question?
Original post by janetconner
such event occurs in an artery supplying blood to the brain, there is reduced blood flow to the brain, they don't have sufficient oxygen to respire hence brain cells die


Yeh fam, i wrote that. Cant believe i remembered that from last year lol

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Original post by ollielee
I put cytokinesis and then questioned myself cause it didn't look like the right word.. so I crossed it out and put cell division. That might have been a silly move :/


I said prophase for A and Telophase for B. Is that ok? I said it because the mass of the cell increases during prophase when chromatin thickens and when spindle fibres and centrioles form. And in Telophase the cell separates into two cells so the mass of the new cell is half.....
I don't know if it's right
Original post by Hayley Williams
i agree! what the hell is that question?


It was near the end. Aftwr the questions about similarities between plants amd animal hormones
Original post by Hayley Williams
i agree! what the hell is that question?


Was that the one where it had more chromosomes so more dna so more base sequences so higher chance of mutation so characteristics change with a higher chance so more likely new species or some **** made
Original post by alexandralilley
I think the exam was better than last year's one. They could have made it much worse
What did people put for the one about the significance of plants having more than one set of chromosomes to create new species?


I was talking about more genes can be present in genome so more favorable triats can be expressed lol I dunno maybe it was to due with increased genetic diversity so less suseptible to larger range of diseases
Original post by games211
yeah but in the book doesn't the ape learn to get the banana by using the baskets to climb on :smile: oh acc your right :frown: loooooool


but the example in the textbook about insight learning is how the monkeys learned to reach the bananas. surely this is a reward too but is classified as insight?? :/
Original post by alexandralilley
I think the exam was better than last year's one. They could have made it much worse
What did people put for the one about the significance of plants having more than one set of chromosomes to create new species?


Is this the polyploidy question?
If it is...I put down that the original domesticated plant by artificial selection is sterile. So it's crossed with a wild plant to make a polyploidy plant which is still sterile. Then it undergoes random mutation and its crossed with goat grass to make another polyploidy plant which is fertile.
Original post by alexandralilley
It was near the end. Aftwr the questions about similarities between plants amd animal hormones


can't remember and i didn't leave any questions?
Did no one put meiosis 1 and meiosis 2 for the first question?? Because I'm such in the description above the question it said it was happening in the testes so it completely threw me!
Original post by yusraa_96
but the example in the textbook about insight learning is how the monkeys learned to reach the bananas. surely this is a reward too but is classified as insight?? :/


Im 100% sure it is insight learning and not operant conditioning

Anyway, it's 1 mark fam
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Original post by Lilenthia
I said prophase for A and Telophase for B. Is that ok? I said it because the mass of the cell increases during prophase when chromatin thickens and when spindle fibres and centrioles form. And in Telophase the cell separates into two cells so the mass of the new cell is half.....
I don't know if it's right


i said the same!
Original post by georgieshack
Did no one put meiosis 1 and meiosis 2 for the first question?? Because I'm such in the description above the question it said it was happening in the testes so it completely threw me!


but i swear it said like different types of nuclear divisions HELP PLEASE :frown:
Original post by georgieshack
Did no one put meiosis 1 and meiosis 2 for the first question?? Because I'm such in the description above the question it said it was happening in the testes so it completely threw me!


No I put mitosis and meiosis, but I don't know....
Original post by alexdonnelly
Has anyone made an unofficial mark scheme? If so can where is the link?


here is one I started but it's rubbish, post 4577
Ok gonna start an unofficial MS, add what you remember!

-What kind of division is 1 and 2?
Mitosis (1) and meiosis (2)
-What happens to DNA at A and B? I have NO IDEA but I put
A: replication (1), B: division (1)
-Genetic variation (9):
prophase 1 crossing over and chiasmata, metaphase 1 independent assortment of chromosomes, prophase 2 ditto, metaphase 2 indpt assortment of chromatids. Mutations, random mating, not sure what else...
-What are the bases? (1? 3? not sure on marks here)
AAACTTC or something, 1 base repeated 3 times, 1 repeated twice? I think.
-TAT complete (not sure on marks)
TATTT[A]CC (again, not sure but I think it was TATTT then something and ended with CC?) Basically you had to copy the last few letters on the diagram but staggered
-How do they sort the fragments of diff sizes? (3)
I think it was electrophoresis but think there has been debate on this thread. Then describe electrophoresis
-Describe the data with the black and white graph (4? 3?)
I said black increases until 1922 or something then decreases, white is v low between certain years then increases, always fluctuates about 1500 FYI pretty sure this would only get one mark, probably had to compare black and white overall as well? idk
-shooting thing is accurate, is it reliable? or something (3)
I said accurate because it is a definite number but it doesn't tell you how many others were there
-something about the wolves
-factors before and after wolves introduces (7)
I put biotic: predators, parasites, pathogens; abiotic: weather, prey, water. Should prob have put intra/interspec competition too. Then after the wolves are intro'd, predator-prey relationship...?
-Bronchioles, how does the diameter reduce? (3?)
Muscles are damaged? Cannot contract?
-why does that mean they can't exhale easily? (1)
not much force because...?
-why does salperetol or something not work on 14%? (3?)
because mutation means they do not have a gene that codes for the receptors so it has no effect on the cells
-why does the other one work? (2)
because the mutation might mean receptors for the other meds are made
-is this experiment reliable? (1)
Maybe they will accept either if they are well-justified and include: sample size, control

that's all I can remember, blacked out for the last questions it seems! Add add add
Original post by BioAgent
I was talking about more genes can be present in genome so more favorable triats can be expressed lol I dunno maybe it was to due with increased genetic diversity so less suseptible to larger range of diseases

I kinda said something like that. I completely bull****ted that one :') i put it was able to asexually reproduce but can create a new species so can have genetic diversity to resist diseases. I wrote it in a better way than that though lol
you know what eff this whtas done is done I probably failed but who cares unis overrated anyway. :cry2:
Lool I wrote on my test for the long mark question that there are many sperms loooooooooooooooooooooooooooooooooooooool I can imagine the look on the examiners face looooooooool
Original post by Lilenthia
No I put mitosis and meiosis, but I don't know....


I think it was mitosis and meiosis! Damn I was so close to putting that aswel

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