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AQA A2 Biology BIOL5 - 17th June 2015

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Each row must add up to 100% of bases, so you just add up 38, 20 and 24 and subtract that from 100, then do the same for the other row :smile:

Thank you!! :smile:

Reply 941

RebeccaHoran

Original post by jessicasydes1

Are you sure? My teacher just told me they can't because they leaked some stuff and about grade boundaries for different papers are different so it's unfair , I'm really stressed about it

I'm sure I just had the reserved exam today, and people were saying that apparently AQA couldnt get the reserve papers in time to all areas

Reply 942

joannaly246

How do you do this question I'm so confused :///:

Reply 943

dianajxox

Can someone help with question 5(a)(i) and 5(b)?

http://filestore.aqa.org.uk/subjects/AQA-BIOL5-W-QP-JUN11.PDF

Reply 944

Turdasaurus Rex

Original post by joannaly246

How do you do this question I'm so confused :///:

What paper is that from?

Reply 945

Ozy96

Original post by Cpie21

Could you sort of bullet point what you'd talk about with ions? Thanks :smile:

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VengefulCandy has included a nice out of spec info on it which is:
"Hydrogen carbonate ions and calcium ions are combined to form calcium carbonate in shells found in clams. However, increasing acidification of sea water by excess hydrogen ions formed by dissolving of CO2 from global warming is weakening the shells and making them brittle."

I would also include:
H+ Could be used in terms of photosynthesis and respiration (NADPH, NADH)
Nitrates in nitrogen cycle
Cl- in CFTR and inhibitory response in a synapse and in cholera.
Oral rehydration therapy for cholera - consists of K+ to stimulate appetiate
Ca2+ in muscle contraction and in in vivo cloning
Mg2+ for chlorophyll production.
Na+-K+ pump in maintaining a resting potential and its role in absorption from broken down food molecules.
Fe2+ In haemoglobin combines with 4 O2 molecules.

Reply 946

Ozy96

Original post by joannaly246

How do you do this question I'm so confused :///:

What's the question? ._.

Reply 947

Thebest786

I understand what happens in action/resting potential, but can someone explain when and what is hyperpolarasation and depolarisation and what they mean etc?

Reply 948

78Saab

Original post by Thebest786

I understand what happens in action/resting potential, but can someone explain when and what is hyperpolarasation and depolarisation and what they mean etc?

Depolarisation is when +40mv is reached so Na+ voyage gated channels close and K+ channels are opened causing repolarisation of the axon.

More K+ ions diffuse out which cause the electrical gradient to fall below -70/-65 mv - hyperpolarisation.

Posted from TSR Mobile

Reply 949

Ozy96

Original post by dianajxox

Can someone help with question 5(a)(i) and 5(b)?

http://filestore.aqa.org.uk/subjects/AQA-BIOL5-W-QP-JUN11.PDF

Screw 5a i, I didn't get it whatsoever. For b they tell you they've already made a cut with BAMH1 so to get 3 fragments we need 2 more cuts

Reply 950

may_1

I'm screwed for tomoz

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Reply 951

Thebest786

Original post by 78Saab

Thanks

Reply 952

Vengefulcandy

Original post by Ozy96

Screw 5a i, I didn't get it whatsoever. For b they tell you they've already made a cut with BAMH1 so to get 3 fragments we need 2 more cuts

for a) your just stating that somewhere along the base sequence of the unknown DNA there is one recognition site that Kpn1 cuts which produces the two fragments of DNA. The other cut is on plasmid.

Reply 953

joannaly246

Original post by Turdasaurus Rex

What paper is that from?

It's basically a exam question pack all on genetics and DNS technology

Reply 954

joannaly246

Original post by Ozy96

What's the question? ._.

Oops sorry! Here it is

Reply 955

prophetkid

https://www.youtube.com/watch?v=zOG4E0vEMUo
Synoptic Essay Predictions

Found this earlier on in the thread and thought I would share it again. Nice little video and definitely worth watching if one of the predicted essays come up!

Reply 956

djhodnett

does someone have 'out of spec' info for an essay on CO2

Reply 957

MollyMcFly1

So if they don't get all the reserve papers out in time and some sit one paper and others the other, surely they'll have to have two separate sets of grade boundaries??

Reply 958

prophetkid

Some people said that if a paper is stolen and they produce a new paper etc. Then the grade boundaries are lower no matter what.
It doesn't make sense to me though. Anyone have any ideas?