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Edexcel B3 Biology - June 16th 2014

Reply 20

Angelo12231

14

Original post by Skygliderjack

As said above they will probabley allow for a range as I got 6+4 instead of 3 because I counted it as 4 extra hours

I got 8 hours :3 still within range?

Reply 21

Decerto

OP

15

Original post by Angelo12231

You know the questioned about plants flowering, it said 85% had flowered so how many were flowering? i did 0.85x500= 425 then 500-425= 75

Because 425 flowered so 75 are still flowering? i am correct

it was 2 marks so i thought it can't be as simple as 0.85x500... so i looked at the question again and realised they said 'flowered' but then asked 'flowering'. Past and present, very sneaky... I think grade bounds will go down significantly ...

Two marks could be given for doing 85/100 * 500 = 425.

Answer + calculation.

But if it is what you say, they are sneaky. :tongue:

Reply 22

Angelo12231

14

Original post by Decerto

Two marks could be given for doing 85/100 * 500 = 425.

Answer + calculation.

But if it is what you say, they are sneaky. :tongue:

i think im right... im not sure, its just that nearly everyone in my triple class put 425... i just really don't know but the question did sound like 425 had already flowered so how many are flowering? I dont know :3

Reply 23

Angelo12231

14

I also think it was 75 plants because if it was 425, then the question would ask ''how many had flowered'' instead of the original question which was ''how many are flowering'' which would be the sum of the flowers which haven't flowered yet...

Reply 24

Angelo12231

14

I got 800,000 for the estimation... i think it would be a range from 700,000 to 900,000

Reply 25

Angelo12231

14

last 6 marker: chyminase (or whatever), invertase, lactase

Reply 26

Angelo12231

14

Dehydration question: Dehydration= pituitary gland releases ADH= more ADH=More water Absorption= hydration

Reply 27

Angelo12231

14

multiple choice was corpus luteum

Reply 28

Angelo12231

14

ways of identifying bone= 1) carbon-14 dating, 2) studying fossil (there was a third but only 2 needed)

Reply 29

Shadowninja107

5

1 1/2 days to revise C3.although it's probably the easiest of all the unit3s

Reply 30

Angelo12231

14

advatages of mitochondrial DNA= 1) there is lots of it 2) high mutation rate i believe... 3) Mitochodnrial DNA less likely to degrade

Reply 31

unimaginable118

3

I think I've done so badly in all three biology exams omg :frown:

Reply 32

Angelo12231

14

i think grade boundaries for an A will be 45, A* would be 52. Why? because it is either you didn't do so well and got a B, or you did great and got an A*... hence the 45 for an A i dont think there was an inbetween for this test

Reply 33

Angelo12231

14

Oh yeah, ways to use monoclonal antibodies: 1) identify cancer 2) identify blood clots. (someone help me make a mark scheme)

Reply 34

Grand-Master

Original post by Angelo12231

advatages of mitochondrial DNA= 1) there is lots of it 2) high mutation rate i believe... 3) Mitochodnrial DNA less likely to degrade

How is high mutation rate an advantage over the nuclear DNA???I wrote that as its only from the mother there will be more or less no variation???

Reply 35

Grand-Master

Original post by Decerto

I got 9, but edexcel will probably allow for a range.

I dont understand i thought it was 6+6+3=15 wtf did i do???

Reply 36

Angelo12231

14

Original post by Grand-Master

How is high mutation rate an advantage over the nuclear DNA???I wrote that as its only from the mother there will be more or less no variation???

high mutation rate makes it easier to date fossils. We are both correct...: Unlike nuclear DNA, which is inherited from both parents and in which genes are rearranged in the process of recombination, there is usually no change in mtDNA from parent to offspring. Although mtDNA also recombines, it does so with copies of itself within the same mitochondrion. Because of this and because the mutation rate of animal mtDNA is higher than that of nuclear DNA,^[32] mtDNA is a powerful tool for tracking ancestry through females (matrilineage) and has been used in this role to track the ancestry of many species back hundreds of generations.

(edited 9 years ago)

Reply 37

Liss16

Original post by Angelo12231

I got 800,000 for the estimation... i think it would be a range from 700,000 to 900,000

What was the question?

Reply 38

Grand-Master

Original post by Angelo12231

high mutation rate makes it easier to date fossils. We are both correct...: Unlike nuclear DNA, which is inherited from both parents and in which genes are rearranged in the process of recombination, there is usually no change in mtDNA from parent to offspring. Although mtDNA also recombines, it does so with copies of itself within the same mitochondrion. Because of this and because the mutation rate of animal mtDNA is higher than that of nuclear DNA,^[32] mtDNA is a powerful tool for tracking ancestry through females (matrilineage) and has been used in this role to track the ancestry of many species back hundreds of generations.