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Edexcel B3 unofficial markscheme 19th June 2017

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Dont think so because the plasmid the gave the name of is different to Bt toxin. I think you would have to mention it if it explicitly said so

It was irrelevant to what toxin so it would just be ignored.

Reply 161

Zaki1039

Original post by sassyvoldemort

Nope it clearly said "MALE with haemophilia"

Yeah i had to read the question like 3 times to make sure i actually get the percentage right, i got 25% since one of the genotypes was Xh Y which is a haemophilliac male

Reply 162

stephen1011

Original post by oliver45456

It wasn't it said children

Nope, a "boy" - it's a 3 marker question and they gave you what allele to use. The first mark is for correctly drawing the square. The second mark is for correctly identifing that the proberbility is out of the boy section. The third mark is for you correctly stating that out of the 2 boys who have a 50% chance of being born; given that they are a boy (as stated in the question), the chance of them inheriting the disease is out of those boys - 1/2 = 50%

Reply 163

__sahar

https://www.thestudentroom.co.uk/sho...rimary_content

THIS LINK FOR THE UNOFFICIAL MARK SCHEME COME AND HELP BUILD IT UP!!!

Lets start a mark scheme

1) Species 2
b) C
c) Co-evolution between moths and orchid
4) Moth gets more nectar to itself/food

2) Keeps them safe increasing chance of survival
b) Primrose flowers are short day plants, helps them get pollinated by right insects.
c) Caterpillars will not get eaten by the prey increasing chance of survival

Punnet square question on haemophilia
25%

UREA is produced in the liver due to the breakdown of excess amino acids

1st six marker
Primary produces less antibodies as it takes longer for the B-lymphocytes to produce antibodies.
However, it leaves memory lymphocytes behind.
secondary infection, the memory lymphocytes produces a lot more in the SAME TIME (2 days) before we see the graph falling. IT takes longer for the graph to fall (the antibodies to lower) due to the abudnce of antibodies in the blood.
primary response first infection of pathogen in body
immune response is formed as lymphocytes divide and antibodies bind to the antigen
destroy the pathogen, then memory lymphocytes are in the blood.
A rapid secondary response is triggered with 2nd infection
memory lymphocytes
rapid response of lots of antibodies to destroy the pathogen, most likely before symptoms can be felt.

HOW IS VEGETARIAN CHEESE PRODUCED? (4 MARKS)
- made using CHYMOSIN
- produced by GENETICALLY MODIFIED ORGANISMS
- CHYMOSIN initiating CLOTTING
-Chymosin and yeast production in fermenters
- REDUCED use of RENNET (which is extracted from animals)

2nd six marker
lactose converted by lactase to glucose and galactose
sodium alginate
calcium chloride
Keep the milk with the beads for around 15 minutes and at 40 degrees celcius. These are the optimum conditions.
nylon guaze and syringe beads are put in
Glucose test strip
lactose encapsulated in beads
glucose test strip shows it has been converted to glucose and galactose

Transgenic plant question
Restriction enzyme
Ligases enzyme
Sticky ends
Vector
Infects plant so DNA incorporated into plant
crown galls

This is what I have so far, if you could help me remember the question I can write more.
comment your answers below !!

Reply 164

username3059654

My final answer is 50%. It asked for the 'percentage of male haemophilics' meaning the percentage of males with haemophilia. correct me if I'm wrong.

(edited 6 years ago)

image1.jpg220.8KB

Reply 165

stephen1011

Original post by apk1

Think this settles the fact that the final answer is 50%. Science teacher agreed.

Thank you! finally someone who isn't thick!

Reply 166

Oliver4214

Original post by stephen1011

Thank you! finally someone It said what is the probability of the baby being a haemophiliac male

Reply 167

oliver45456

It was 25% lol. I asked my science teacher after and she said so

Reply 168

Amelia Louise

Original post by stephen1011

Thank you! finally someone who isn't thick!

It's 25%, it was the chance of the baby being male and a haemophiliac - not a male baby being a haemophiliac (which would have been 50%)

Reply 169

jacobabdi123

That paper was actually so easy apart from the last six marker, cuz like a donut I didn't revise it. But to be fair I have been doing all of my revision the night before. Ah well, you win some, you lose some.

Reply 170

jacobabdi123

Original post by Amelia Louise

It's 25%, it was the chance of the baby being male and a haemophiliac - not a male baby being a haemophiliac (which would have been 50%)

Word.

Reply 171

oliver45456

Think i got something between 47 and 51. could that be an A star

Reply 172

jayrx

What was the answer for the ADH multiple choice question?

Please let it be 25%

Yes Oliver! You're on a roll mate!

Original post by oliver45456

Think i got something between 47 and 51. could that be an A star

Reply 175

d22oo

Original post by spikelee3138

Did anyone get the sacchromyces cervisiae for the yeast question?

Reply 176

VictorGon

I got angry at Edexcel when they asked what the name of the yeast for inveterate was. I don't speak Latin, it's supposed to be a multiple choice question

Reply 177

Bartholemew

Original post by hanzmamsmmx

i need the mark scheme where can i find it

Did you find one?

Reply 178

xxxtentacionn

The way the questions were worded in this paper were harder than the beat drop in Look At Me !_!

Reply 179

Zaki1039

Original post by oliver45456

Think i got something between 47 and 51. could that be an A star

Definitely, a lot of peeps in my school found the exam hard. Hopefully the boundaries will be faiely low compared to last year as i feel this paper was much harder.

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