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AQA Biology B2 - Unofficial Mark Scheme

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Parents Phenotype = Brown hair : Red hair Parents genotype = Bb : Bb Gametes genotype = B - b : B - b Offspring genotypes = BB Bb Bb bb (1 in 4 chance / 3:1 ratio) Offspring genotypes = Brown hair : Brown hair : Brown hair : red hair

Reply 361

hannahb9184

Original post by Blahblahblah7

That's what I put I think and I revised it quite well

Phenotype is whet you see e.g. Brown hair
Genotype is what's there e.g. Bb
And for Dad I put XY and mum is XX

i put this aswell but people are saying its wrong ohwell

Reply 362

Spiket

The question asking for the estimated number of plants in a field was 160,000 i think as the quadrant was 25cm X 25cm meaning the total area in m2 would be .25*.25*10 to give .635m2 so there are 32 plants per m2 and 32*100*50=160,000

Reply 363

hansa123

Original post by Naco88

It said that it was an example of the equipment that you can use but if you used all 3 then it will probably get you the marks. :smile:

you also had to talk about how to make the test valid eg by using quadrats, transects etc.

Reply 364

Macym

what about the stem cell questions about an advantage and disadvantage to using stem cell from a childs own umbilical cord ??????

Reply 365

Ahmed74

Does anyone else think that this was piss hard and that b3 was much better?

Reply 366

funky2722

Original post by Macym

what about the stem cell questions about an advantage and disadvantage to using stem cell from a childs own umbilical cord ??????

it is okay because it won't have thical problems, since the cord cant form a whole new organism, but it will be rejected.

Reply 367

funky2722

Original post by hansa123

you also had to talk about how to make the test valid eg by using quadrats, transects etc.

no you didn't go away

Reply 368

theholychilli

Plantains question's answer was 1600, all of my class got this. Also an advantage for hydrogen peroxide question is that is does not require a high temperature

Reply 369

Yusuf90

For quadrats question:
0.25m x 0.25m = 0.0625m^2
0.0625 x 10 = 0.625m^2 (Total area of 10 quadrats)
20 ÷ 0.625 = 32
32 x 5000m^2 = 160000 plantains in total
Is this correct and will it get all the marks?

Reply 370

YAY GCSE

Original post by funky2722

it is okay because it won't have thical problems, since the cord cant form a whole new organism, but it will be rejected.

Wasnt the question just: why would using stem cells from the childs umbilical cord not help the childs genetic disorder?

Reply 371

Spiket

Original post by Yusuf90

Thats what i got and number seems reasonable for such a large area

Reply 372

hansa123

Original post by funky2722

no you didn't go away

yes you did just because you didnt doesnt mean you have to be a stubborn cow

Reply 373

coreHelp

GUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUYS

did we have 2 six markers in b2??????????//

Reply 374

funky2722

Original post by coreHelp

GUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUYS

did we have 2 six markers in b2??????????//

yh think so

Reply 375

funky2722

Original post by hansa123

yes you did just because you didnt doesnt mean you have to be a stubborn cow

this is for the photosynthesis 6 mark question right?

Reply 376

GCSE_core

Original post by coreHelp

GUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUYS

did we have 2 six markers in b2??????????//

1, b3 had 2

Reply 377

funky2722

Original post by theholychilli

Plantains question's answer was 1600, all of my class got this. Also an advantage for hydrogen peroxide question is that is does not require a high temperature