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OCR Biology A Exam Thread (Breadth - May 26, 2016 and Depth - June 7, 2016)

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half of what I learn. Won't come up, it sucks
Reply 321
Avatar for plower
plower
9
Original post by Dharaa
have you found an answer for this? coz i really have no clue what this is about



No idea as well 😤 We don't need to know about spearmans rank and chi squared do we?
Original post by xsrajabx
Revise over the circulatory systems and ECG's


Posted from TSR Mobile


Do you think this is likely to come up?
You also need to know that if it goes back into optimal pH it will work as normal again. But if pH has changed too much it will denature and can't change back even in normal pH
Original post by plower
No idea as well 😤 We don't need to know about spearmans rank and chi squared do we?


Spearmans rank yes
Chi squared I've never heard of and never been taught it, but some people saying we need to know it?
biology q.png could any of you help me on this Q? I understand what it's asking but wondering if there's an easy way to calculate it.....good luck everyone tomorrow!
Original post by OddFuturez
How does pH effect enzymes ?


Proteins are long chains of amino acids that are folded into their tertiary structure using hydrogen, disulfide, ionic bonds and hydrophobic-hydrophillic interactions. The tertiary structure determines the shape of the active site. The interactions and ionic bonds obviously have charges so for e.g. if its too acidic thats many H+ ions which interfere with the charges causing the bonds to unravel and break. I heard someone here say that it is reversible but i'm pretty sure its irreversible because the interactions have been broken, but yeah if it unravels it means the protein has been denatured and the substrate can no longer bond.
Hope this helps you understand why the enzyme gets denatured etc :smile:
Original post by brodingoson
biology q.png could any of you help me on this Q? I understand what it's asking but wondering if there's an easy way to calculate it.....good luck everyone tomorrow!


LOL I just did that question too.
I did 1*2^n>100000
2^n>100000
n>log2(100000)
n>16.6
so n=17 years.
Sorry if you don't do maths.
Original post by Simbak6
Proteins are long chains of amino acids that are folded into their tertiary structure using hydrogen, disulfide, ionic bonds and hydrophobic-hydrophillic interactions. The tertiary structure determines the shape of the active site. The interactions and ionic bonds obviously have charges so for e.g. if its too acidic thats many H+ ions which interfere with the charges causing the bonds to unravel and break. I heard someone here say that it is reversible but i'm pretty sure its irreversible because the interactions have been broken, but yeah if it unravels it means the protein has been denatured and the substrate can no longer bond.
Hope this helps you understand why the enzyme gets denatured etc :smile:


It is reversible but only if the pH has not changed by too much. If it is too much then it denatures like you said but if only a little it can be returned to normal by going back to the optimal pH
Reply 329
Avatar for S.G.
S.G.
22
Does anyone have the locked specimen papers please?
Original post by invisiblegirl
i know, wish it was still spilt into f211 and f212, as there is wayyyyy too much to revise, I'm struggling with the 2015 specimen paper as we have no mark scheme


I agree theres just too much to learn. Isn't the specimen paper on the OCR website and it does have the mark scheme right at the bottom
Original post by 4nonymous
LOL I just did that question too.
I did 1*2^n>100000
2^n>100000
n>log2(100000)
n>16.6
so n=17 years.
Sorry if you don't do maths.


Hahah i did the same way as you!! but because its 1 mark it seemed to complex for the average biology student haha, thank you tho
Original post by 4nonymous
I agree theres just too much to learn. Isn't the specimen paper on the OCR website and it does have the mark scheme right at the bottom


no its not, the 2014 one is but my teacher gave us that with the 2014 specimen paper, can't seem to find or access the 2015 one
Reply 333
Avatar for plower
plower
9
Original post by 4nonymous
LOL I just did that question too.
I did 1*2^n>100000
2^n>100000
n>log2(100000)
n>16.6
so n=17 years.
Sorry if you don't do maths.



Why 2 * 1?
Original post by haes
is there anywhere i can get a list of all definitions for bio :/


back of your OCR textbook?
Original post by plower
Why 2 * 1?


its 1*(2^n) not 2*1
because you start with one and then it doubles each time
Original post by invisiblegirl
no its not, the 2014 one is but my teacher gave us that with the 2014 specimen paper, can't seem to find or access the 2015 one


Isnt it this one?
http://www.ocr.org.uk/Images/171694-unit-h020-01-breadth-in-biology-sample-assessment-materials.pdf
Original post by invisiblegirl
back of your OCR textbook?


If you want to look at definitions, its actually better to use the specification because they also tell you the ones that will be and wont be tested so that way you dont have to learn them all and then realise that you didnt even need to know half of them
Original post by 4nonymous


no thats the 2014 one, which i already have
Totally screwed for biology tomorrow, even more so for chemistry on Friday.

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