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OCR 21st Century Science B4 B5 B6 10th June 2016

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Sorry I said it wrong! Yeah there is a higher concentration of nitrates in the plant and therefore active transport tries to overcome this by going from low to high concentration! Sorry!
Original post by Ben.M
If active transport goes against the concentration gradient, from low to high, then would there not be a higher concentration of nitrates in the plant roots? Then the plant uses active transport to get nitrates from the soil into its roots.



Original post by subwayislife
if it was low concentration to high concentration wouldn't that mean that there is a higher concentration of nitrates in the plant than in the soil because it needs to move from a low concentration (in the soil) to a high concentration (in the plant)?
any predicted 6 markers? how do you predict them?
Original post by MezmorisedPotato
Six Marker Predictions

1/ B5: Cell cycle i.e mitosis or something on meiosis of organisms comparision question.

2/ B4: Active transport

3/ B6: Reflex arcs in animals for survival.


how did yo come up with these predictions?
Original post by MezmorisedPotato
Six Marker Predictions

1/ B5: Cell cycle i.e mitosis or something on meiosis of organisms comparision question.

2/ B4: Active transport

3/ B6: Reflex arcs in animals for survival.


how did you come up with these predictions?
Original post by idkyimhere
how did you come up with these predictions?


Based it on previous years and what has not been asked in a while. B5 and 4 has limited six markers they can ask really. B6 has lots of content so anything could come up.
Guys, what did you get for the ratio question.

I got 1:639


Posted from TSR Mobile
Reply 26
Original post by Callump1904
Guys, what did you get for the ratio question.

I got 1:639


Posted from TSR Mobile


I got 1:64 , don't know how you managed to get that
Reply 27
Original post by Callump1904
Guys, what did you get for the ratio question.

I got 1:639


Posted from TSR Mobile


I also got this answer.
Original post by Iqsar
I got 1:64 , don't know how you managed to get that


I also got 1:64
Reply 29
Original post by Iqsar
I got 1:64 , don't know how you managed to get that


Because the TOTAL population is 64,000,000 and the number of people AFFECTED is 100,000. Therefore, the number of people who are unaffected is the TOTAL - the AFFECTED so 64,000,000 - 100,000 = 63,900,000. Therefore, the ration of affected to unaffected is 100,000:63,900,000 (when divided by 100,000 it becomes 1:639).
Original post by Eueu
Because the TOTAL population is 64,000,000 and the number of people AFFECTED is 100,000. Therefore, the number of people who are unaffected is the TOTAL - the AFFECTED so 64,000,000 - 100,000 = 63,900,000. Therefore, the ration of affected to unaffected is 100,000:63,900,000 (when divided by 100,000 it becomes 1:639).

Crap I misread the question
Reply 31
I got 1:639 too. And 0.09% for the percentage of DNA in the mitochondria?
Reply 32
Original post by Ben.M
I got 1:639 too. And 0.09% for the percentage of DNA in the mitochondria?


I got 0.09% for the mitochondria but misread the ratio question
Was stage A or stage B mitosis?
Original post by babbajung
Was stage A or stage B mitosis?

I said stage B
Reply 35
Did you draw a straight line or curve for line of best fit? Does it matter?

For the estimate I got around 41 arbitrary units
Original post by Aishoolimoo
I said stage B


How come?
Original post by babbajung
How come?


I said it was mitosis as is produced a zygote which has 46 chromosomes which is the normal number in body cells. I said stage A was meoisis for the opposite reason. I have no idea if that's close to right though.
Original post by ry_s99
Did you draw a straight line or curve for line of best fit? Does it matter?

For the estimate I got around 41 arbitrary units


I did a curve as it's a limiting factor graph and got 42
Original post by Aishoolimoo
I said stage B


I got stage c

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