AQA A2 Biol4 January 2012 pre- exam discussion

But energy released from carriers chain is only used to make ATP directly in photosynthesis right, not on the inner membrane of a mitochondria.

I think your book might be summarising it a little too much. I have a text book that says the same but it's not the case. When it says the energy released goes towards making ATP, it's actually talking about all the steps in which protons are pumped and what not. So don't get confused, it never happens DIRECTLY - that's only in photosynthesis.

Fantastic, thanks a lot. We seem to have raced through this unit and missed out a lot of the smaller details.



Unfortunately the question was the other way round, the advantages of natural over artificial, but thanks anyway Adds to my list of pro's/con's!

This seems correct
How are you revising for this? I've pretty much done but still not confident at all
Stupid HSW

Thanks, that actually makes it a bit better. I'm beginning to think too much and think of the whole thing as separate steps but it's really the same step.

anyone got any idea why the grade boundaries are so low? did a paper today and was shocked you only need 39/75 for an A*?

Was 57 for jun 11, 52 for jan 11, i guess it will be around 57-60 this time. To be fair i did worse on the papers with lower boundaries so it is fairly accurate

How do you know what the grade boundaries are going to be without even seeing the paper...awk

he said he'll 'guess it will be around 57-60 this time'

lolololol

Before sitting the paper?
Wow. Extraordinary

yeah if you can guess what topics came up by looking at previous papers, then you can estimate it definetly

I think your book might be summarising it a little too much. I have a text book that says the same but it's not the case. When it says the energy released goes towards making ATP, it's actually talking about all the steps in which protons are pumped and what not. So don't get confused, it never happens DIRECTLY - that's only in photosynthesis.

Hi, having done several papers, I've managed to come out with fairly good A's having got pretty rubbish results - which is typical AQA.

However, I did the specimen paper today that was given to us by school and got 44/75 - which is definitely not good. The problem is, I can't find any grade boundaries online, actually I'm not even sure if AQA release GB's for these - does anyone happen to know?

Also, it is definintely the general consesus that over the last year, the grade boundaries have risen because the content in the paper is easier? (I don't have the june 2011 paper and will do the jan one as a mock at school apparently, so I haven't actually looked) Or is it because AQA are tightening the boundaries?

Sorry this is long, but thanks

Just to add, the protons are not pumped INTO the inner membrane. They are pumped into the space between the inner membrane and outer membrane. Then they diffuse back into the matrix.

Don't think there are grade boundaries for the specimen paper but they are renowned for being very dodgy since the mark schemes don't get checked like the final ones do...
And yeh to the content getting easier i reckon, i did a few papers within about 2 weeks in december and got the higher marks in the papers which had higher grade boundaries...also i think the ridiculously low boundaries of the first 2 papers where due to the backlash after those exams, plus them being the first of the 'new style' of exams