A2 Biology OCR June 2015 Revision Thread

Did you pull off a C4 all nighter??

Same man, how did you find c4? and what board you doing for maths?

Looks quite accurate to me, apoptosis and meiosis QWC would be ideal, labelling/functions of brain looks likely too

What do we even need to know about this so confused..

What do we even need to know about this so confused..

Basically, there was wheat, and it crossed with a grass, and was sterile<br />
Then it had a chromosome mutation and became fertile<br />
Then it was bred with other species of wheat to produce another fertile hybrid, it was fertile cos it had an uneven no of chromosomes so it couldn't pair<br />
It then went through another chromosome mutation where it doubled no. of chromosomes, so it became fertile again<br />
Further gene mutation lead to modern bread wheat<br />
Recently, other genes have been added eg. disease resistant <br />
And now they're continuously breeding for best yield etc etc all that artificial selection<br />
<br />
thats the story of wheat

Ahh mate, if there was a QWC on meiosis and apoptosis, i would literally cry lol, hope there is, iA.

I got less than 4hours sleep last night for c4 which I think worked out well in the end. One final push and it's all over.


OCR for maths. It went pretty well, so I'm hoping to gorge off the energy from doing well in that for the rest of the night

The ones for epistatsim, but you can work it out from the punnett square

Yeh surely they've got to put it in one year or another? Then again can never predict with these OCR pricks

Why is sterile air entered into fermentation vessels rather than normal air?

so emotionally drained bc of this exam my body can't take anymore

Timber management guys? Could someone simplify it into bullet points for me please? I would be soo grateful!! Cheers!

SMALL SCALE
Coppicing - cutting a tree close to the ground to encourage new growth, whilst keeping it alive - sustainable. It regrows new shoots over and over to be used

Pollarding - similar to coppicing, but higher up on the tree eg, branches - used when there are lots of deer as the deer eat the growing shoots from coppiced trees so it takes a while to grow back (when it's cut higher they can't reach it)

ROTATIONAL coppicing - dividing woodland into sections and only cutting from that section once a year, until they've all been cut - this means that the ones from the beginning are ready to be cut again as they've left them to grow. Good for biodiversity - different woodland areas provide different habitats (different amounts of light in woodland in diff areas), so biodiversity is larger


LARGER SCALE
Selective cutting - removing only largest, most valuable trees so habitat isn't affected much

Clear-felling - cutting down ALL the trees in one area at one time - rare in UK, leaves soil susceptible to erosion, soil can run off into waterways and pollute them because there are no trees to protect

I do not understand why this isn't in my book in the slightest