Edexcel Biology (Unofficial) B2 Mark Scheme.

I said the question one differently. I said bacterial cells have chromosomal DNA and plasmids and sometimes a flagellum. Do you think I wouldn't get the marks because I worded it differently?

The answer to the graph pH question about enzymes (it was with the yeast cell question). Here's how I worked it out:
Sucrose was higher, lactose lower (I think?) so I connected the dots and did some maths.
I divided the lactose result by the sucrose result for both pH 9 and pH 7 and got the same answer, so I timesed that answer by the sucrose result for pH 5 and got 16 with decimal places, rounded it up to 17 so the answer was 17.

Nope - I asked before the start of the exam and they told me to do the one I was entered for. A bunch of other people had been switched without being told, too. It's an absolute joke. Unless I cough up £50 to switch the next two exams I'm going to be stuck on a paper I should not have been entered for.

Additional Science is the one subject I really struggle in and they've gone and done this to me. I suppose the A in the CATs might boost my grade a little, but there's only so much that they can do.

why would you divide them both though? when surely they both have different properties meaning they denature and produce different levels of carbon dioxide at different Ph's. i got 42

I divided it because I thought that maybe there is a scale for it so only a certain fraction of the result for sucrose will appear in lactose. I thought that if they have the same fraction of sucrose result produced in lactose result for both of the pH's, then I could do the same for pH 5.

For example, if sucrose produced 500 at pH 9, 700 at pH 7 and sucrose got 250 at pH 9 and 350 at pH 7, the fraction produced would be a half so if the result for sucrose pH 5 was 100, for lactose it would be 50.

I see, i think the question wasn't a very good one because it could either decreased or increased as by pH 9 it could have denatured a lot meaning less CO2 production or pH 9 could be optimum pH meaning it could have been a higher percentage released.

I'm not sure, i mean i guess it said estimate because it could of increased or decreased

Yeah "estimate" threw me off, but I assumed that's why as well.

Well, the good thing is, is that its only worth 1 mark. What do you think the grade boundaries would be like? And also do you know how many marks the Watson and Crick question was?

3 marks I think!

I missed the six marker on the back page!! I didn't even see it!! Anybody else? Praying for low grade boundaries

Ah thats annoying i thought it was 2, and i spoke about the wrong scientists' work

You'd probably get credit for recalling the names though!

@olivia1066 awh, so unlucky! I almost made that mistake myself. Just remember for future GCSE science exams though that there are always two six-markers per paper - so if you see one and not the second, you know you've missed one :P

@chrlhyms Watson and Crick was two marks, I think

I think grade boundaries will increase this year: I found the test more challenging than past papers because it tested application of biology far more than it did content knowledge but I don't think too many found the test exceptionally difficult, hence why I think grade boundaries will increase. I'd be tempted to say 52/53 for the A*.

I thought that Watson and Crick used crystallised DNA and then x-ray beams but its Wilkins and Franklin but I didn't say the names

Any thought about A?

Its 42 because the table showed that as the pH decreased by 2, the (whatever it was) increased by 7 (I think it was 7). So it looked like this:

pH: Sugar: (Whatever it was)
9. fructose. 28
7. fructose. 35
5. fructose 42. ----> this is the answer you should have got - the question was testing our ability to notice trends.

@olivia1066 awh, so unlucky! I almost made that mistake myself. Just remember for future GCSE science exams though that there are always two six-markers per paper - so if you see one and not the second, you know you've missed one :P

@chrlhyms Watson and Crick was two marks, I think

I think grade boundaries will increase this year: I found the test more challenging than past papers because it tested application of biology far more than it did content knowledge but I don't think too many found the test exceptionally difficult, hence why I think grade boundaries will increase. I'd be tempted to say 52/53 for the A*.

Maybe 45/46ish? Then 37/38 for a B and 30/31 for a C.

All guesses, though.