AQA A2 BIOL5 22nd June 2012

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Reply 1980

lmao nah it was good, do you know if we need to know about the 2nd messenger stuff

Oh yeah that's mentioned in the spec so yes I would defo learn it :biggrin:

Have you compared the June 10 paper and June 11 paper? Whatever isn't in those two may come up this time...but I can't ever predict with these AQAers :/

Reply 1981

Jessica_94

Original post by Sockhead

Difference between proto-oncogene and oncogene? Thanks

a proto-oncogene stimulates cell division however if a proto-oncogene is mutated, it becomes an oncogene which stimulates cell division excessively and cells divide too rapidly leading to the formation of a tumour. So basically an oncogene is a mutant proto-oncogene

Reply 1982

SashaLuLu

Original post by ZahraSmiley

Ahhh okay so it doesn't really matter where I put it then as long as it related to the question, I guess I'll put it in homeostasis but if I'm running out of points I'll try and scam the examiner by putting it as a different point :colone:

(it won't work)

Yeah that was a bit strange really, haven't seen it in negative feedback but I thought cause they regulate cell division it might be? No idea at all.

And thank you :biggrin:

No problem! Yeah i see what you mean with the cells etc, but i personally would not risk it as you may lose 1/2 marks for irrelevant or wrong material when you've got plenty for feedback which is enough to score 20+ marks, so i personally would not risk it unless you find out it is definitely an example of feedback!
Good luck :smile:

Reply 1983

rss.914

Original post by ZahraSmiley

Oh yeah that's mentioned in the spec so yes I would defo learn it :biggrin:

Have you compared the June 10 paper and June 11 paper? Whatever isn't in those two may come up this time...but I can't ever predict with these AQAers :/

ohh kl thanks, and not really have you? im just hoping restriction mapping doesn't come up

Reply 1984

. . .

What is the standard structure for the essay?

Reply 1985

Master.K

I would hate for menstrual cycle to come up! :frown:

Reply 1986

Dollyandra

Original post by Jessica_94

i would beable to write about 2 lines :frown:

no joke

Carbohydrates, by definition, are compounds containing carbon, hydrogen, and oxygen, so there's loads to talk about!

This means you can talk about a-glucose, storage as cellulose (branched, insoluble etc), b-glucose, digestion of starch, deoxyribose, reducing/non-reducing sugars, blood glucose regulation, production of glucose/other hexose molecules in light independent cycle, breakdown of glucose in glycolysis, the role of carbs in cellular communication (carb part of glycoproteins), triglycerides, saturated/unsaturated fats in CHD/health/blood pressure

I can't think of any more but that should be broad enough! Hope I helped :smile:

You'll be fine once you get in there!

Reply 1987

bubbletrouble

Original post by ILikeToEat

Partial digest is when restriction endonucleases don't cut the plasmid at all the restriction sites. If you think of it in terms of lots of plasmids being digested at once, you'll have some being completely digested and some partially. The partially digested bits could combine with other plasmids, so you'd end up with pieces of DNA longer than the original piece.

As an example, say you had a 10 base long strand of DNA, that was cut at 5, 3 and 2. A partially digested strand might only be cut at 8 and 2. The 8 could join with another whole plasmid making 18.

So if there are longer strands than the original, it's due to partial digestion. Just remember its in terms of hundreds of plasmids, never just 1!

that was a really good explanation, thanks!

Reply 1988

jessplease

How many 6 mark/long questions do they tend to put in? if any?

Reply 1989

JackMitchell29

Does anyone know if the comparison between the hormone system and the nervous system is essential?

Nervous System. Hormone system.
-transmitted by specific neurones. -Transmitted by circulatory system.
-Effect localised by neurone anatomy. -Effect localised by target cell receptors.
-Fast acting. -Slow acting.
-Short response. -Long response.

I wrote ^^^^ in my notes a while back and i cant remember why :s-smilie:

Reply 1990

TheDeviant

Original post by sarwara05

neg feedback - thermoregulation, regulation of blood glucose, regulation of blood water potential, control of ventilation, control of hearrt beat, metabolic pathways, population stability, oestrus cycle, selection.

homeostasis - and I don't know except for maybe water potential :s-smilie:

have I answered your question? :smile:

Where regulation of blood water potential and control of ventilation on the spec? I don't remember anything about them, but I think there's stretch-receptors in the lungs which presumably work like pacinian corpuscles...

Regulation of blood water potential? Regulated by chemoreceptors? Hydrostatic pressure? Suddenly my AS revision seems a lot less complete :s-smilie:

Reply 1991

JackMitchell29

ALSO, will someone go through PARACRINE SIGNALLING with me please

Reply 1992

ZahraSmiley

Original post by SashaLuLu

Yes you're right, better not to include them and take the risk.

Good luck to you too :biggrin:

Reply 1993

salad_fingers

Original post by sarwara05

have I answered your question? :smile:

What do metabolic pathways have to do with negative feedback? I can only think of increasing rae of metabolism / respiration to generate heat when it's cold, but that's thermoregulation really

Reply 1994

Jessica_94

Original post by Dollyandra

You'll be fine once you get in there!

aw thankyou! helped me alot :smile:

Reply 1995

ZahraSmiley

Original post by rss.914

ohh kl thanks, and not really have you? im just hoping restriction mapping doesn't come up

Nah haven't compared them yet but I will do after I have a run through unit 5 once more. There's a bus strike tomorrow fml. Out of all days...ofc it has to be on my exam day.

Ahh me too, they just kill the bio paper tbh :frown:

Reply 1996

freddy

Original post by Sockhead

Difference between proto-oncogene and oncogene? Thanks

an oncogene is a mutated proto-oncogene

an oncogene affects cell activity in 2 ways:

the oncogene can code for excessive growth factor which bind to cell surface causing increased cell division

or the oncogene can activate the receptor protein permanently so cell divison is stimulated even in the absence of growth factors.

these 2 changes both lead to increased cell division hence a tumour.