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Edexcel GCE Biology Unit 5 6BI05 June 2013

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Reply 920
For anybody still stuck on the pre-release revision, I have uploaded a document which may be of use.
http://getrevising.co.uk/resources/pre_release_2013_questions_practice
Anyone got the pre-release material for PAST PAPERS? (So we can do Section C of past papers)
Original post by bubblegummer
Hmm... that makes sense :smile: mind if you explain how does a positive feedback work? it happens during hypothermia right?


positive feedback is when effectors promote a change. For example, in the case of the development of athersclerosis, blood pressure is the cause. It damages the endothelial lining of arteries, so platelets clump on the wound. Cholesterol then settles on the clump, forming and atheroma. This increases blood pressure further, so more damage occurs....

I'm not sure what you mean by hypothermia in this context. Can you elaborate?
Reply 924
Original post by Lujain Al Omari
positive feedback is when effectors promote a change. For example, in the case of the development of athersclerosis, blood pressure is the cause. It damages the endothelial lining of arteries, so platelets clump on the wound. Cholesterol then settles on the clump, forming and atheroma. This increases blood pressure further, so more damage occurs....

I'm not sure what you mean by hypothermia in this context. Can you elaborate?


so whats the difference between negative feedback and positive feedback?
Original post by TheNoobyPotato
hello, could anyone explain this bit in the mark scheme please? The question was about comparing auxins to hormonal control:

4. speed of action compared e.g. slower in plants,
some animal hormones are faster ;
5. duration of effect compared e.g. some animal
hormones have a shorter term effect ;

Why is speed faster in animals? is it just the fact that the hormones reach their target faster in blood?
And also, the whole duration thing. I thought animals would have a longer duration, such as testosterone effecting males over years, whereas auxins take a few hours.. But I understand that something like adrenalin would take a shorter time than Auxins. So would either be acceptable - the mark scheme is SO ambigious?


All your deductions are correct. Some hormones travel faster in blood and have shorter effect (Adrenaline), others have long term effect (testosterone)
Keep in mind the mark scheme keeps saying 'some'
Reply 926
Original post by I Hate Edexcel
I've done a lot, but still have a lot to go. Thankfully I did unit 4 back in Jan.


Mind telling, what grade did you achieve?
Original post by Sravya
so whats the difference between negative feedback and positive feedback?


negative feedback is when the effectors oppose the change occurring.
For example, core body temperature rises, this is detected by thermoreceptors that send impulses to the hypothalamus, the hypothalamus causes sweat glands to produce and release more sweat, core body temperature increases, this is detected by thermoreceptors, hypothalamus stops send impulses to the sweat gland, so sweating stops
Reply 928
Original post by Lujain Al Omari
negative feedback is when the effectors oppose the change occurring.
For example, core body temperature rises, this is detected by thermoreceptors that send impulses to the hypothalamus, the hypothalamus causes sweat glands to produce and release more sweat, core body temperature increases, this is detected by thermoreceptors, hypothalamus stops send impulses to the sweat gland, so sweating stops


Thanks :smile:
Reply 929
Original post by Aishahhhhh
Does anyone have the mark scheme for this paper which opens as a pdf?


wht year ? Jan or June ?
Original post by Abod
Mind telling, what grade did you achieve?


I managed to get an A* by some sort of miracle haha
Original post by ramanan
wht year ? Jan or June ?


The January 2013 6BIO5/01 please
Original post by I Hate Edexcel
I managed to get an A* by some sort of miracle haha


there is an A* for unit 4?
stepping into the thread out of the blue, i m not going to study for much longer, bloody exhausted after all this, so tomorrow afternoon, i ll be free from my exams, last one!!!!! i really need to get a high grade to get into uni, good luck everyone, tomorrow afternoon around 4pm, freeeeeeeeeeeeeeeeeeeeeeeeee !!!!!!!!
I hate not knowing what the last section is going to be like. I just don't know what to expect.
Reply 935
Original post by Maybenexttime
Anyone got the pre-release material for PAST PAPERS? (So we can do Section C of past papers)


it was somewhere in the old post, try this if u haven't started to prepare for part C
http://www.thestudentroom.co.uk/showpost.php?p=41915038&postcount=32

http://www.thestudentroom.co.uk/showpost.php?p=42241375&postcount=72
Reply 936
a bit confused when markschemes used word potential difference and de-polarisation... can someone please explain the difference? thanks
Reply 937
Original post by Aishahhhhh
The January 2013 6BIO5/01 please


6BI05_01_rms_20130307.pdf

here u go :smile:
Reply 938
I can't wait for the exam to finish and discuss how sh1t the exam went :rolleyes:


omgg thankyou so much been looking for this for agesss :tongue:

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