EDEXCEL IAL January 2017 biology unit 1

I don't think the grade boundaries will be high, atleast lower than last year

What was the answer of the last question ( the difficult part )?

what was the answer to the question that asked why we would need a buffer solution?

PH is a variable that affects the work rate of an enzyme, so if no buffer, ph can cause enzyme to denature, buffer acts as a controlled variable for the ph so the only variable present is enzyme concentration (which is what were testing or that's the reason we are doing the experiment)

I think it was because of the presence of fatty acids in the solution.As tryglyceride were forming the fatty acids were reducing so the ph could alter as a result to that.to keep it a fair experiment buffer was used

the M S Z allele one? im not sure that question took me the longest, I came up with, M dominant, Z recessive, I said at first S is co-dominant but our teacher said no co dominant in a-level so I said s is recessive as well, a top student in our country (got 8a* in o level) said he wrote their all co-dominant and M was the most influential co-dominant then S then Z, im not sure tbh

Was the last questions answer 25 percent probability? The Question related osmosis,the rbcs ruptured in solution Q right?

Was the last questions answer 25 percent probability? The Question related osmosis,the rbcs ruptured in solution Q right?

can someone confirm wether the rbc shrink or burst . cause i assumed it shrink but a reasonable amount of my friend s are saying that it burst