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Edexcel A2 Biology Unit 5 (6BIO5) - 22/06/2011- OFFICIAL THREAD !

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By the way, have you guys been told about the mistake in the article;
On page 3, paragraph 6, the sentence should read:

Researchers at the biotech company Chiron in Emeryville, California, reported similar results in a 1998 trial that used AAVs to deliver the epo gene to two baboons.

To be honest it doesn't make much difference just thought I would tell ya :wink:
Reply 2501
Avatar for amnah_70
amnah_70
Original post by hey-hey-hey
has anyone got 2011 jan snab mark scheme? pleasee

Also on the article, im a bit confused because it says bit on
Catching Cheaters, 4th paragraph, states that:
people with plenty of red blood cells should have little or no eop circulating in the blood.Surely the concentration of eop should be higher?? because they injected the gene for it, so more epo was produced?! to make higher red blood cells, epo is required. How can they have high red blood cells with low epo? shouldnt it be high, then we know if they took it-cheaterd.
please help me, i dont understand.


6BI05 MS Jan 2011.PDF
Original post by amnah_70


wow thanks!! thats really good!! :smile:
was that made by your teacher?
Reply 2503
Avatar for amnah_70
amnah_70
Original post by hey-hey-hey
wow thanks!! thats really good!! :smile:
was that made by your teacher?


no not my teacher, someone elses teacher who posted this a couple of days ago :smile:
omg.. i feel really bad...
i revised well.. and i just began solving June 2010.. its easy.. but I can barely remember anything :s-smilie:S :s-smilie: !
Original post by amnah_70

Original post by amnah_70


Wow that was quick!! thank you!! i was looking everywhere for this, edexcel want username, password for this.
Thanks! +rep!
Original post by hey-hey-hey
has anyone got 2011 jan snab mark scheme? pleasee

Also on the article, im a bit confused because it says bit on
Catching Cheaters, 4th paragraph, states that:
people with plenty of red blood cells should have little or no eop circulating in the blood.Surely the concentration of eop should be higher?? because they injected the gene for it, so more epo was produced?! to make higher red blood cells, epo is required. How can they have high red blood cells with low epo? shouldnt it be high, then we know if they took it-cheated.
please help me, i dont understand.


It's a negative feedback system so as RBC levels go up, epo goes down and when RBC decrease, epo increases to restore the norm value for RBC. It can be used to distinguish those who used the EPO gene therapy or those with natural mutations because they will have high RBC levels AND high epo levels which shouldn't happen as negative feedback system usually counteracts any increase in RBC with a decrease in epo.
Forgive me, i know this has been asked to death...

The difference between ACCOMMODATION and ADAPTION?
Original post by sparkle*92

Original post by sparkle*92
It's a negative feedback system so as RBC levels go up, epo goes down and when RBC decrease, epo increases to restore the norm value for RBC. It can be used to distinguish those who used the EPO gene therapy or those with natural mutations because they will have high RBC levels AND high epo levels which shouldn't happen as negative feedback system usually counteracts any increase in RBC with a decrease in epo.


thankyou!! now i get it! :smile:
Reply 2509
Avatar for lbavfc
lbavfc
In terms of EPO receptors, where are they? Do the same receptors trigger the production of EPO as well as combine with it to activate second messenger?
Reply 2510
Avatar for Coatseh
Coatseh
Hey, does anyone have the June 2010 mark scheme?
Original post by sparkle*92
It's a negative feedback system so as RBC levels go up, epo goes down and when RBC decrease, epo increases to restore the norm value for RBC. It can be used to distinguish those who used the EPO gene therapy or those with natural mutations because they will have high RBC levels AND high epo levels which shouldn't happen as negative feedback system usually counteracts any increase in RBC with a decrease in epo.


I think the way it is written in the article confuses the issue slightly. As I see it, it is as simple as this: if they test someone and they have heightened RBCs after a period of rest, then it should be fair to say they are using EPO.

JP
Original post by Maria1234
Explain differences in the mechanisms of substances like IGF-1 and MGF, and transcription factors such as FOXO???????????????????


Could be ...

IGF-1 and MGF are protein growth factors and should work in a similar way to protein hormone EPO ... activated/released because of stress -> binds to receptor -> activates 2nd messenger -> protein kinase cascade -> genes for muscle proteins (e.g. actin, myosin) transcribed and translated.

FOXO transcription factor -> inhibted by IGF-1 and insulin -> when not inhibited, binds to promoter region of DNA -> atrogenes transcribed and translated -> atrogens break down muscle proteins (e.g. actin and myosin).
Reply 2513
Avatar for amnah_70
amnah_70
Original post by Coatseh
Hey, does anyone have the June 2010 mark scheme?


6BI05 MS June 2010.PDF
Reply 2514
Avatar for Coatseh
Coatseh
Original post by amnah_70


Lifesaver cheers
Anyone got a quick link to all past papers and mark schemes? Thanks in advance :wink: x
Original post by lbavfc
In terms of EPO receptors, where are they? Do the same receptors trigger the production of EPO as well as combine with it to activate second messenger?


Seeing as EPO is pumped from the kidneys when o2 levels are low, would it be fair to say that chemoreceptors are used to detect this? They can be in arteries. The hormone then travels to the bone marrow where it activates the second messenger inside cells to produce more red blood cells.

At least, this is how i understand it!

JP
Reply 2517
Avatar for avig613
avig613
Original post by Choca Mocha

Original post by Choca Mocha
okayyy, so what happens to Na+ then?


Nothing.
Anyone know the grade boundaries for the June 2010 paper????
Original post by Jammers123
Anyone got a quick link to all past papers and mark schemes? Thanks in advance :wink: x


http://vle.havant.ac.uk/Biology_web/exam_papers.htm

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