AQA Biology A2 Unit 4: Populations and Environment - 16th June 2016

5 markers are literally the least of my worries, its the question 7 that drives me up the wall

Tell me about it! I've learnt the answers will mostly be 'avoid bias, representative sample, reliable so statistical tests can be carried out, sets a benchmark' for like all of question 7 :smile:

if the S.D overlap, results aren't significant etc

Reply 381

Boundless_x

16

Original post by hopingmedicinae

5 markers are literally the least of my worries, its the question 7 that drives me up the wall

In every paper I'm literally fine until I hit question 7, and I end up only getting half the marks or less :frown:

last years was pretty good but 2010 one was horrible :s-smilie:

Reply 382

Elizabeth_rose14

1

Original post by Kaya22

i like the cgp but i do find it goes into too much depth for me :/ i dont really like learning stuff aha

How do you do so well then? I have to like really learn stuff because I get stressed and then forget things... (Seriously jealous of your mind power right now...)

Reply 383

Unipits

Original post by SI 1

Could someone briefly explain the krebs cycle and ETC. I never know how to condense the information down for the 3 markera

For ETC say electrons pass through electron transport chain which provides energy for changing the shape of the protein, so allowing hydrogen ions to be pumped into the intermembrane space. This causes a chemiosmotic gradient so hydrogen ion pass back into the matrix through atp synthase which provides energy to combine adp+pi into atp.So to summarise for a 3 markerElectrons pass through electron transport chainWhich provides energy for pumping H+ into intermembrane spaceH+ ions go through atp synthase providing energy for synthizing atp

Reply 384

joebush

1

Original post by Robert2798

Jesus, fair enough haha, and with what people were saying about CHEM 4 today it seems like anything could happen.

After CHEM4 and Core 3 maths I'm pretty confident that just about anything could happen. AQA are on a roll this year with strange, hard exams.

Reply 385

thomaarrss

2

Original post by hopingmedicinae

speciation came up last year
so did mark release capture

won't be about those i think

someone mentioned co2 differences through the year, i think maybe that
- fertilisers
- The carbon cycle (idk why this does seem likely to me)
- Selection, how the mean moves over a certain period of time maybe
- How climate change affects plant and animals

what 5 points could you write about fertilisers??

Reply 386

Sacred Ground

19

Original post by thomaarrss

what 5 points could you write about fertilisers??

Replace lost nutrients
Applied in the form of soluble granules which contain ammonia
Ammonia combines with oxygen to form nitrites
Nitrites converted into nitrates by nitrifying bacteria
Nitrates used to build protein and amino acids
Increased plant productivity

That's just a guess haha

Reply 387

Applicant75235

12

Original post by Unipits

For ETC say electrons pass through electron transport chain which provides energy for changing the shape of the protein, so allowing hydrogen ions to be pumped into the intermembrane space. This causes a chemiosmotic gradient so hydrogen ion pass back into the matrix through atp synthase which provides energy to combine adp+pi into atp.So to summarise for a 3 markerElectrons pass through electron transport chainWhich provides energy for pumping H+ into intermembrane spaceH+ ions go through atp synthase providing energy for synthizing atp

I thought the energy released when elecron go down electron carier provide energy for oxidative phophorylation whic combines adp and Pi then this atp is used for activly tranposrting or pumping the H+ ions?

Reply 388

Applicant75235

12

Original post by Sacred Ground

Replace lost nutrients
Applied in the form of soluble granules which contain ammonia
Ammonia combines with oxygen to form nitrites
Nitrites converted into nitrates by nitrifying bacteria
Nitrates used to build protein and amino acids
Increased plant productivity

That's just a guess haha

I never get when do we say ammonium ions or ammonia?

Reply 389

thomaarrss

2

Original post by Sacred Ground

Replace lost nutrients
Applied in the form of soluble granules which contain ammonia
Ammonia combines with oxygen to form nitrites
Nitrites converted into nitrates by nitrifying bacteria
Nitrates used to build protein and amino acids
Increased plant productivity

That's just a guess haha

thank you! is the nitrogen in fertilisers in the form of nitrates or ammonia, nitrates would be better wouldnt they??

Reply 390

Sacred Ground

19

Original post by koolgurl14

I never get when do we say ammonium ions or ammonia?

It doesn't matter to be honest, usually nitrogen fixation fixes nitrogen gas into ammonium ions and ammonification (saprophytes decomposing proteins in organic matter) produces ammonia

Reply 391

hopingmedicinae

4

Original post by koolgurl14

I never get when do we say ammonium ions or ammonia?

So basically Nitrogen is actually fixed TO ammonia which dissolves to form ammonium ions in soil; hence the distinction

Reply 392

Sacred Ground

19

Original post by thomaarrss

thank you! is the nitrogen in fertilisers in the form of nitrates or ammonia, nitrates would be better wouldnt they??

It can be either, however, ideally fertilisers will contain nitrates so the plants do not have to carry out nitrification - this makes the nitrates readily available to the plant whereas if the fertiliser contained ammonia it would take longer for the plant to produce nitrates. You could mention this in a question though

Reply 393

thomaarrss

2

Original post by Sacred Ground

It can be either, however, ideally fertilisers will contain nitrates so the plants do not have to carry out nitrification - this makes the nitrates readily available to the plant whereas if the fertiliser contained ammonia it would take longer for the plant to produce nitrates. You could mention this in a question though

i guess a mixture would be benificial, something like ammonium nitrate, nitrate for use straight away then ammonium for nitrate in the future

Reply 394

lahigueraxxx

2

When to say saprobiotic microorganisms and when to say saprobiotic decomposers???

Reply 395

charlie2466

12

What would be write for a 6 mark question on natural and agricultural ecosystems????

Reply 396

lahigueraxxx

2

http://filestore.aqa.org.uk/subjects/AQA-BIOL4-QP-JUN15.PDF

http://filestore.aqa.org.uk/subjects/AQA-BIOL4-W-MS-JUN15.PDF

for 3b, can you say increased biodiversity for the last point???

Reply 397

shellypatel2

1

Original post by koolgurl14

I thought the energy released when elecron go down electron carier provide energy for oxidative phophorylation whic combines adp and Pi then this atp is used for activly tranposrting or pumping the H+ ions?

The energy released when electrons move down carriers is used to pump H+ ions by a proton pump into the inter membrane space membrane. when the electrons reach their final electron acceptor (Oxygen), H+ are transported into the matrix by ATP synthase down their electrochemical gradient by chemiosmosis, (ADP+Pi->ATP) and 2H+ + 2e- + 1/2 O2 form water (waste product)