AQA A2 Biol4 January 2012 pre- exam discussion

Actually wait, they both produced a offspring that were female and male both hairless so the girl must have inherited both Xd from parents, not tell me how that works if you have XDxd XDy? it doesn't

No, they only produced male hairless offspring... I think..

Reply 1781

Drex

Original post by XFire

What did people put for the 35C qn for the pigs? Why scientists don't do measurements at higher temperatures? I mentioned the mean growth rate being lowest but then didn't know where the next mark was, or if that's even a mark.. :/

Apparently it was because the efficiency of the last result and the one before were the same or something.

Reply 1782

Mission

Original post by XFire

What did people put for the 35C qn for the pigs? Why scientists don't do measurements at higher temperatures? I mentioned the mean growth rate being lowest but then didn't know where the next mark was, or if that's even a mark.. :/

Energy efficency was the same for 30 and 35 so repeat measurements not needed.

Reply 1783

izzwizz

Original post by barzy_j

Actually wait, they both produced a offspring that were female and male both hairless so the girl must have inherited both Xd from parents, not tell me how that works if you have XDxd XDy? it doesn't

I'm confused with the above bit.
But
XD Y
XD XDXD XDY
Xd XdXD XdY

25% male no hair

Reply 1784

stealth_writer

4

What did people for every pig Q

What about the trees and plants Q

Reply 1785

EffKayy

16

Original post by Mission

Energy efficency was the same for 30 and 35 so repeat measurements not needed.

I said that but it was worth 2 markssss :'( life sucks haha

edít: sorry but i get all panicky and suicidal after every exam hahah

Reply 1786

Drex

Original post by juliewho

I got confused, wrote about quadrats, then thought they wanted a method like percentage cover in each quadrat, then I switched it to a transect. Not really sure what I was supposed to be writing about.

I put a belt transect with randomly distributed quadrats on it. Then calculate population density per quadrat by dividing the number of marram by the area of each quadrat...dunno if it's correct...

Reply 1787

JesusIsMyHomeboy

9

God, I really have no idea how this has gone!

Reply 1788

alexissocool

5

Original post by Drex

For the single celled one I think any one of

More of it would be eaten (as it doesn't have bones etc)
OR
It has a higher net productivity idea would do.

I said the first point; the fact that more of the single celled algae will be eaten. I so hope that's right. It's logical but I think timing was such an issue, at this point I skipped that question and then came back to it after I did the questions at the end.

Reply 1789

NutterFrutter

I doubt the grade boundaries will be higher than June 2011, question 7 on that paper was much easier than the question 7 on this paper, if anything grade boundaries will be slightly lower..

Reply 1790

EffKayy

16

I also talked about percentage cover :ninja:

Reply 1791

Nuss

12

How was people's timing, I didn't get to finish the HSW question, so lost around 10 marks cos I didn't even get onto it

Reply 1792

izzwizz

Original post by Drex

Apparently it was because the efficiency of the last result and the one before were the same or something.

Wouldn't it cause health problems to the pigs, denaturing enzymes etc over 35oC

Reply 1793

NutterFrutter

Original post by izzwizz

Wouldn't it cause health problems to the pigs, denaturing enzymes etc over 35oC

No, it said they can survive above that temperature.

Reply 1794

EffKayy

16

What did you guys say about the nitrate concentration decreasing?

Reply 1795

pearl25

5 extra minutes would've made so much difference in this paper!

Reply 1796

alexissocool

5

Original post by Drex

I put a belt transect with randomly distributed quadrats on it. Then calculate population density per quadrat by dividing the number of marram by the area of each quadrat...dunno if it's correct...

Oh I spoke about percentage cover of marram as it was asking for the distribution rather than the abundance of which you would just count the number of marram plants right? But I did speak about the systematic sampling along transects.

Reply 1797

izzwizz

Original post by EffKayy

I talked about number of marram grasses on the line transect and how it was systematic

Reply 1798

laughingbagel

For the "proof that it's on the X chromosome", would I get a mark for saying that any female offspring from a cross with a father with hair, would always have hair themselves, as the X from the father must always be passed on to the daughter; and then I used an example - although it only happened once in the diagram so it's not really proof that it always happens?