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AQA Biology AS New Spec - 26th May and 7th June

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Original post by lilyjacks
for the question on Alzheimer's and it said why can it fit 2 active sites I said because antigen variability😂, was such a hard paper, what did everyone get for the ror at 10c I got 11


I put the induced fit model, so both the enzyme's active sites alter slightly allowing them to act on the same substrate?
What was the answer to the statistical test?
I messed that one up :angry:
Original post by Namita Gurung
What was the answer to the statistical test?
I messed that one up :angry:


Pretty sure it was T Test
Original post by CrazyFool229
Pretty sure it was T Test


Great
The statistical tests was the one area I didn't get to revise
Original post by Namita Gurung
Great
The statistical tests was the one area I didn't get to revise


it was only one mark anyway apparently - Don't worry too much about it.
Original post by saulgreen
I put the induced fit model, so both the enzyme's active sites alter slightly allowing them to act on the same substrate?



I said the protein structure is extremely similar
Original post by saulgreen
People are talking about a few statistical tests.... is my school the only one who didn't do statistical tests? I'm pretty sure its not in the spec!! All I know is the sign test from psychology and I know thats wrong so I just left the question blank :|


same here but i think its in the front of the book with all that how to science crap i read it but totallly forgot the names snd reasons so :'( your not alone
Original post by CrazyFool229
it was only one mark anyway apparently - Don't worry too much about it.


Yeah
I actually thought that the whole test was alright. Just some bits I'm unsure on.
Original post by saulgreen
I put 10cm3 of the inhibitor and 90cm3 of water to make 100cm3 of the inhibitor with a concentration of 1000 nmol dm-3. Because they started with 10000, so 10000 x 0.1 (90%) = 1000 and therefore you put 90cm3 of water - not the inhibitor. If you do it the other way round you are diluting it by 10% to get 9000 rather than by 90% to get 1000. I think thats right anyway... my maths sucks tbh


Yessss omg i did that too. Phew
Reply 209
Avatar for SANTR
SANTR
8
What did you guys write for the question on the last paper:
The one on why they had side effects?
And the one on mutation?
And I think one the other one was on peptides on something?
Original post by SANTR
What did you guys write for the question on the last paper:
The one on why they had side effects?
And the one on mutation?
And I think one the other one was on peptides on something?


Side effects I put as a result there would be too much whatever Alpha protein that was
Original post by Namita Gurung
Yeah
I actually thought that the whole test was alright. Just some bits I'm unsure on.


For the rates graph what did people put the explanation as and did peoples like go ofd then level out 10-12? Didnt put it in standard form aswell:frown:
Reply 212
Avatar for SANTR
SANTR
8
Original post by CrazyFool229
Side effects I put as a result there would be too much whatever Alpha protein that was


What about for the one after the Q on why both enzymes can act on the substrate?
Original post by SANTR
What did you guys write for the question on the last paper:
The one on why they had side effects?
And the one on mutation?
And I think one the other one was on peptides on something?

I said there will be an accumulation of the substrate because there was a decrease in the amount of a-secretate and also because of the b-secretate being inhibited?
Reply 214
Avatar for Gswp
Gswp
7
what was the second function of protein Y and how could you tell it was a cell membrane?
Anyone got an unofficial markscheme or copy of the questions?
Original post by SANTR
What did you guys write for the question on the last paper:
The one on why they had side effects?
And the one on mutation?
And I think one the other one was on peptides on something?


The stimulus piece they gave said the protein that leads to the formation of alpha-amyloid (i think that was the name of the protein?) is only ONE of the products of the reaction of beta-secretase. So I put that by inhibiting the enzyme and preventing the reaction from happening means that the other products of the reaction aren't being synthesised and these could be necessary for the body's normal functioning - hence the side effects.

The mutation causes sufferers to have a higher chance of having more beta-secretase; which therefore synthesises the proteins that lead to the formation alpha-amyloid, leading to more plaques in the brain.

Not sure what peptide question you're talking about
(edited 7 years ago)
Original post by Luchamb
For the rates graph what did people put the explanation as and did peoples like go ofd then level out 10-12? Didnt put it in standard form aswell:frown:


I just did a bit of explaining on why the rate increased and quoted some figures off the graph. Then yeah, I said it leveled off and then gave some explanation why, etc.
Original post by SANTR
What about for the one after the Q on why both enzymes can act on the substrate?


I put that the tertiary structure could be the same but only the secondary structure may change as one was Alpha and one was Beta so they could have similar shaped active sites

Original post by Epitype
I said there will be an accumulation of the substrate because there was a decrease in the amount of a-secretate and also because of the b-secretate being inhibited?


If the B Secretate was being inhibited then surely it means that there is a higher probability of the substrates forming an E-S Complex with A secretate and therefore form more of the A protein? I'm probably wrong
Original post by Gswp
what was the second function of protein Y and how could you tell it was a cell membrane?


Not sure of the function, I think that it acts as cell recognition site? Above the diagram it said (something along the lines of) 'figure 3 showing plant cells manufacturing cellulose for their cell walls' and so you can tell from the diagram that the cellulose is leaving the membrane to be part of the cell wall. The cell surface membrane is next to the cell wall whereas other plasma membranes (e.g. the ones around organelles) are not so thats why it was the cell surface membrane

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