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Aqa gcse b3 thread

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ack, what did people put for the question about using biogas being pumped back into the fermenter(?) i know i got it wrong but i think i wasn't worth too many marks...
anyone remember how much it was worth? :s-smilie:

i think it was 2 marks? or maybe 1 :s-smilie:

Reply 41

megank

I put so gases cannot escape??!

Reply 42

ilovechemistry

hey, you know for the weird counting bacteria one..
i got: 22, 8800 and 880000 or something like that, anyone else?

Reply 43

scaryassmonster

Original post by ilovechemistry

hey, you know for the weird counting bacteria one..
i got: 22, 8800 and 880000 or something like that, anyone else?

yh that should be right.

Reply 44

thepastpaper

Original post by Felineyx

I threw away so many marks on the question about the heart and blood, and then on the last question. With the blood one, I didn't actually know what it was asking until halfway through writing the answer! Definitely lost some there.

Hopefully I can just get that 78 I need!

omg same here just need that 78 too :biggrin:

hopefully the grade boundaries will be really low like 27 for an A* :smile:

Reply 45

thepastpaper

i think i have failed this exam :frown:

Reply 46

sadzfabulous786

any1 have an idea wht the grade boundaries r roughly gonna b?

Reply 47

garyhe

Original post by sadzfabulous786

any1 have an idea wht the grade boundaries r roughly gonna b?

my teacher said theyre a lot lower this year and seeing as everyone found it so hard....

i think 34 for a*? :s

Reply 48

ilovechemistry

Original post by thepastpaper

i think i have failed this exam :frown:

I think everyone thinks they have, you might surprise yourself :smile:

Reply 49

LuciiAnna

Original post by megank

I feel like crying. all the exams have just been going badly for me :/

Me too :/ i actually cried when i came out of this one it was so horrible, i didn't know what half of the questions were, let alone the answers :frown:

Reply 50

megank

Original post by thepastpaper

omg same here just need that 78 too :biggrin:

hopefully the grade boundaries will be really low like 27 for an A* :smile:

I need roughly around that too :smile:

but i highly doubt 27 will be an A*.. thats abit too low :L

Reply 51

LuciiAnna

Original post by garyhe

my teacher said theyre a lot lower this year and seeing as everyone found it so hard....

i think 34 for a*? :s

Maybe but i hope its MUCH lower, like 29? It has been in the past so fingers crossed :smile:

Reply 52

scaryassmonster

Original post by garyhe

my teacher said theyre a lot lower this year and seeing as everyone found it so hard....

i think 34 for a*? :s

im thinking less. i guess it'll be like 30 ish seeing as so many people found it hard. lets hope its low anyway :biggrin:

Reply 53

Jadb

Original post by garyhe

Just one or two I think? I wrote that it would stir up the mixture and it'd be better than air because air can be easily contaminated with bacteria that would compete with the bacteria already in the fermenter.

Reply 54

Antzlive

Original post by N0body

I drew a curve down since the other graph was going up. (as the number of bacteria increases theoretically number of glucose should go down)
Don't feel to bad though i think i made mistakes some were else thats more worse than a curve

Although you are correct about the curve going down, it should have crossed the x axis at around 34 hours, as that was the time that the microbes above stopped rapidly produced. It was a 2 marker so you must of got 1.

Reply 55

ilovechemistry

I put A for the first one- and 'more CO2 produced from respiration' or something. I think it's wrong though..? :/ I HATE AQA

Reply 56

garyhe

Original post by scaryassmonster

im thinking less. i guess it'll be like 30 ish seeing as so many people found it hard. lets hope its low anyway :biggrin:

lol, that would be great though missing out 15 marks and getting an a*! :biggrin:

Reply 57

Antzlive

Original post by Jadb

I did a downwards curve to 34/35, because the glucose was being used up. I thought it was alright except the last question, may have dropped a few there. What did you guys put for the question on villi?

I made references to the ideas that:
there was plenty of microchondria for respiration
there is a large surface area due to the shape
micro villi only increase surface area
large blood supply, and an explanation of that
short diffusion distance
i also made reference to the idea that it was moist, which may not be exactly true.

I'm sure 3 ideas with good explanations is enough for the full marks.

(edited 12 years ago)

Reply 58

IAmMclovin

sorry guys, but i got 90/100 in core biology, 100/100 in additional and 36/40 in my isa, does anyone know what UMS / grade i need in this paper for A* OVERALL? :frown:

Reply 59

GMD

Original post by Jadb

Biogas is better than air because if you used air, some of it would enter the biogas exhaust tube. Then the concentration of the useful bio gasses (ie methane) would be reduced since now it's mixed with air.