17th May 2016- OCR 21st Century Science B1 B2 B3 Exam

Reply 80

ahmed3140

1

Original post by Ella_08

For raw marks maybe like 45/60

If an A* is 45 then Is okay to say 45 is 90 ums marks, how much marks do you think 95 and above ums marks will be??

Reply 81

MezmorisedPotato

OP

18

Original post by ahmed3140

If an A* is 45 then Is okay to say 45 is 90 ums marks, how much marks do you think 95 and above ums marks will be??

UMS points after 90 isn't too hard to get and sometimes going over the raw mark grade boundaries by just 4-6 marks can give 100UMS. This is because there is a cap off point.

Reply 82

niamhdoesmaths

21

Original post by Ella_08

For raw marks maybe like 45/60

Oh no that's going to be hard to reach!!! If I perform well I a science paper I get around 46/47 but my worst score was 33 so I really don't want the boundary to be as high as 45!! :s-smilie:

Reply 83

username1454260

17

Original post by MezmorisedPotato

UMS points after 90 isn't too hard to get and sometimes going over the raw mark grade boundaries by just 4-6 marks can give 100UMS. This is because there is a cap off point.

yeah, you're right :u:

Reply 84

username1454260

17

Original post by NiamhM1801

Oh no that's going to be hard to reach!!! If I perform well I a science paper I get around 46/47 but my worst score was 33 so I really don't want the boundary to be as high as 45!! :s-smilie:

It's not always. In 2013 it was 41/60. I'm estimating 33 would still be an A, maybe a high B... that was your worst though. Don't worry, just nail the 6 markers - it's amazing how much difference they make :wink:

Reply 85

thannah

Original post by BULL14

Can someone explain how genes are shuffled together randomly to make egg and sperm. Please. I really din;t understand it.

did you mean the process of fertilisation ? which will produce a zygote, have 46 chromosomes (23 from egg, 23 from sperm)

Reply 86

atomc19

11

Original post by thannah

did you mean the process of fertilisation ? which will produce a zygote, have 46 chromosomes (23 from egg, 23 from sperm)

No, I think he means meiosis. But that isn't even in B123

Reply 87

B4sh

13

Original post by ahmed3140

what do you think will be the grade boundaries for an A*??

grade boundaries always vary between 42-48 (in extreme cases) for an a*, but you can really know until after the exam as standard deviation is used when determining the boundaries

really hope its low af this year, im resiting from doing it last year

Could someone explain ADH please? It's my weakness

Reply 89

olivialois

1

Original post by Starlight15

Could someone explain ADH please? It's my weakness

think of it as

LESS
MORE
MORE
LESS and MORE
LESS
LESS
MORE

If more water is consumed into the body, the body will send a message to the brain (proccessing centre) to coordinate a response. The pituitary gland therefore less AHD so the kidneys stop absorbing as much water. This means you will produce a large volume of dilute urine. The process of returning the water levels back to normal is done by negative feedback. If too little water is consumed, the brain (processing centre) co-ordinates a response to get it back to normal levels by negative feedback. The pituitary gland releases more ADH so the kidneys can reabsorb more water. This means less urine is released and is of high concentration.

Reply 90

Usmaan345

2

Anyone got a prediction of what will come up

Reply 91

nitthushz

3

Original post by Ella_08

Sure, pm me ur email

can i also have the 2015 b1-b3 paper please.

Reply 92

nitthushz

3

Can someone please explain natural selection???

Reply 93

olivialois

1

M- Mutation in DNA
V- causes variation within the species
A-can give an advantageous gene
s- therefore this organism SURVIVES as it beats the COMPETITION
R- so when they reproduce
O- their OFFSPRING has this advantageous gene too

can help them survive and therefore evolution occurs over years.

Original post by nitthushz

Can someone please explain natural selection???

Reply 94

suhaislam

4

Original post by Dave50

Hi
Does any of you have 2015 21st century science b1 b2 b3 papers

I did for practice in class, it had 6mq about :genetically identical/not genetically identical twins
Heart disease & heart stuff
Nitrogen cycle with a flow chart for description.

Reply 95

suhaislam

4

Original post by Stressedwbu1

What time are your guy's exam on tuesday?! I'm terrified!

I have French in the morning and b123 @ 13:30

Reply 96

GeorgiaC901

1

Original post by Starlight15

Could someone explain ADH please? It's my weakness

ADH = anti pee hormone

Posted from TSR Mobile

Reply 97

Char4ncubex

4

Original post by olivialois

M- Mutation in DNA
V- causes variation within the species
A-can give an advantageous gene
s- therefore this organism SURVIVES as it beats the COMPETITION
R- so when they reproduce
O- their OFFSPRING has this advantageous gene too

can help them survive and therefore evolution occurs over years.

Oooooh this is good, thanks :smile:

Reply 98

nitthushz

3

Original post by olivialois

M- Mutation in DNA
V- causes variation within the species
A-can give an advantageous gene
s- therefore this organism SURVIVES as it beats the COMPETITION
R- so when they reproduce
O- their OFFSPRING has this advantageous gene too

can help them survive and therefore evolution occurs over years.

Thank you

Reply 99

niamhdoesmaths

21

Ok so I've been revising B123 most of today and I'm a lot more confident about it now - I've still yet to look at B3 properly but I'll do that in the morning as luckily it's an afternoon exam!!
I've partially done 2 past papers (Jan and June 2012) and so far I have got 33/41 in Jan and 41/49 in June so I'm doing quite well! I'll finish them both off after learning B3 and possibly do the June 2014 paper in full if I have time.
I still need to go over controlling water content for B2 but other than that it's all B3 from here!

Also, did anyone who's done the June 2012 paper notice how it was really weird - there are 2 6 markers in B2 and none in B3??? If that happened tomorrow I'd be really happy (as I got 6 and 4) but I doubt it will.

Good luck for tomorrow everyone! :h:

17th May 2016- OCR 21st Century Science B1 B2 B3 Exam

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