OFFICIAL OCR A2 Biology - F214 Thread

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ibysaiyan

Ornithine is ATP dependent :yep:

anyways it was just a mark.
http://en.wikipedia.org/wiki/Urea_cycle

The thing is I'm convinced the arrow was leaving the cycle.

Hence it was the second H20... or at least I though so at the time. :confused:

Reply 3781

lossy1234

Alex-92

I'm trying to explain there is no ATP involved in the Ornithine cycle! If you have the OCR endorsed book by Heinemann (Sue Hocking), turn to pg 40, and look in the bottom left corner. You will see a clear Ornithine cycle. One H20 in and 2 H20 out. This produces one net H20 out per cycle, represented by the equation. In the exam they showed one H20 in and one H20 out on their diagram, so an additional H20 needed to be placed coming out of the diagram, on the arrow leaving the cycle.

:eek3:

ye mate i have never seen an ornithine cycle that has ATP actually being shown in it

Reply 3782

ibysaiyan

Alex-92

Hmm, interesting. I am not aware of it, as we are taught such limited topics. I bet there is ATP involved in the Ornithine cycle, as you say. But for A2 biology, it doesn't mention it :s-smilie:

Written by my gran.

Reply 3783

SHAYAN1369

Guys what did u write about that fish question that had a toxin in it's body...I can't remember the question fully but i said fish has more effective buffer in it's blood and also cuz it lives in water toxin will will get diluted ...something like that.

Reply 3784

Alex-92

lossy1234

ye mate i have never seen an ornithine cycle that has ATP actually being shown in it

Thank you! I'm not going crazy then :eek3:

Reply 3785

lossy1234

DJkG.1

The thing is I'm convinced the arrow was leaving the cycle.

Hence it was the second H20... or at least I though so at the time. :confused:

ye i think that ornithine cycle there is alot more complicated than we needed to know for A2 biology there is no mention of ATP in the spec of textbook in it so i would say its definately water..

Reply 3786

ibysaiyan

Alex-92

Thank you! I'm not going crazy then :eek3:

*facepalm* it is :smile:

anyways whats its all done.

Reply 3787

uer23

For the first question was it Adenosine or Adenine ? Would you get a mark for Adenosine ? (Because the actual name of the compound is (Adenosine Triphosphate) Also would you get a mark for phosphate or did you have to say triphosphate since the bracket covered 3 Phosphate groups.

Reply 3788

Alex-92

ibysaiyan

Written by my gran.

Mmm ok then. Not quite sure what point you are trying to prove by this post, or if you are just joking. I mean wtf? :confused:

Reply 3789

lossy1234

SHAYAN1369

i put it has different shaped Na ion channels so the toxin cant bind to it and block it

Reply 3790

Su_x

SHAYAN1369

one of my friends put that, i put something about the sodium channels in the fish not having the complementary receptor to the toxin and so it didn't affect it.... i don't think that's right though :/

Reply 3791

ibysaiyan

SHAYAN1369

I dont recall much but I wrote about its structure and something to do with irreversible/reversible-inhibition. That for us it causes inhibition but not for the fish itself.

Reply 3792

uer23

Su_x

I wrote something like that too.

Reply 3793

TX22

when i saw the fish question as i turned the page, i was going to die as i thought it was question like the seal one and worth like 3 marks

thank god it was only one mark.

Reply 3794

ibysaiyan

uer23

I wrote something like that too.

Yea.. was two marks so didn't require much detail :yep:

Reply 3795

DJkG.1

uer23

It was the nitrogenous base adenine.

Adenosine is a nucleoside, made of adenine and ribose.

So adenosine for that label is wrong.

Next was ribose. Third I put "triphosphate - made of 3 phosphoryl groups" - didn't quite know what was the perfect answer there. :s-smilie:

But I think they'll accept triphosphate, phosphate or phosphoryl groups.

Reply 3796

ibysaiyan

Yea the question about diabetic type 2 person and his diet that was much of a copy/paste and you had to talk about that he should eat more poly-saccharide rich diet and so on... too much to writing :/
Also the question before it was to deal with B-glucose for cellulose which is not digestible by our digestive system ...... bla bla

Reply 3797

Alex-92

Ok exam is done now. Each to his own. Time for Chem5 revision. :smile:

Reply 3798

In2deep

TX22

16 PAPERS, wow.

i had 6 and i couldnt even cope with that lool.

did you retake AS modules because you did bad or did you just repeat some to boost points?

Very long story but I basically decided last year (my AS year) to do 3 A-levels in a go so I could take a gap year without falling back. I obviously underestimate them and know I'm doing 4 A-levels in a go.

Reply 3799

ibysaiyan

DJkG.1

But I think they'll accept triphosphate, phosphate or phosphoryl groups.

Yep its basically a phosphorylated Nucleotide just as DNA and RNA much closer to rna due to ribose sugar and so on... I wrote everything but the only bit I could remember was the energy given out by each phosphate bond... *facepalm* should be marked full though as I spoke of synthase.. and stuff . Hmm come to think of it now is it 30.5 Kj?