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AQA Biology B2 - Unofficial Mark Scheme

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That's basically what I wrote as well although I mentioned diffusion too (oxygen diffusing from air into alveolus)

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So you didn't mention anything about fatigue or lactic acid either? Do you think we will get the marks?

Reply 441

Anonymous4004

Im sure the glandular tissue in the stomach secretes hydrochloric acid, enzymes and MUCUS to protect the stomach from being digested.

Reply 442

SunnyBoys

Original post by Anonymous4004

Im sure the glandular tissue in the stomach secretes hydrochloric acid, enzymes and MUCUS to protect the stomach from being digested.

I'm pretty sure the 'mucus' you're thinking of is the epithelial tissue that lines the inside and outside of the stomach.
I forgot to write enzymes --'

Reply 443

Akila1

Original post by Comp123

I reckon the grade boundaries were well higher:
50 for A*

Nah 45

Reply 444

Anonymous4004

Original post by SunnyBoys

I'm pretty sure the 'mucus' you're thinking of is the epithelial tissue that lines the inside and outside of the stomach.
I forgot to write enzymes --'

After looking further into this Its pretty confusing. it says mucous is secreted by glandular tissues but also that the epithelial tissue provides a similar function. not completely sure though... different people at my school are saying different things.

(edited 7 years ago)

Reply 445

Akila1

Original post by Rylan110

For the Question about why organs xould be rejected the answers were

-Different DNA
-Different Tissue
-The body could see it as a foreign pathogen and attack it.

as long as you expanded those answers you will get 3/3!

That is quite incorrect. Complying to what would be accepted in the mark scheme;

-1 mark for antigens (specific protein shapes)
-1 mark for white blood cells produce antibodies
-1 mark for which "attack" the antigens on the donor organ

(edited 7 years ago)

Reply 446

Akila1

Original post by Anonymous4004

Yh i thought it could be that but I've searched it and if you look in the Nelson Thornes bio higher book it says mucus is secreted. on the internet it says from gastric glands or specifically goblet cells.

1 mark- glands "secrete/release" substances
1 mark- such as hydrochloric acid
1 mark- and enzymes such as protease (or pepsin)

Reply 447

Anonymous4004

Original post by Akila1

1 mark- glands "secrete/release" substances
1 mark- such as hydrochloric acid
1 mark- and enzymes such as protease (or pepsin)

I hope they made the mark scheme that simple.

Reply 448

Akila1

Original post by Anonymous4004

I hope they made the mark scheme that simple.

They usually do! It is the graphical questions, and the questions which test for logic that have quite obscure answers eg. Suggest reasons...

Reply 449

Everydaygent

Original post by Akila1

1 mark- glands "secrete/release" substances
1 mark- such as hydrochloric acid
1 mark- and enzymes such as protease (or pepsin)

Thank you. It was a 3 mark question and a lot of people are missing this out, glad I wasnt the only one who wrote this. It was a lot of space to write "secretes enzymes and hormones"

Reply 450

Harry578

Original post by Dauntless27

I was just wondering, for the question about the increase in blood flow to the athletes muscles, if I would get the marks for saying that it would mean more oxygen would get to the muscles which means that more respiration could be carried out and more energy would be released. Therefore the muscles would be able to contract to bring about movement. I didn't say anythimg about lactic acid or fatigue and I'm worried that I wont get the marks.
Quite worried about this question because I think I answered it wrong. Any thoughts ???

I wrote the exact same thing

Reply 451

MahMah

Original post by Harry578

I wrote the exact same thing

I believe you would get marks.

Increasing the blood flow rate happens because the blood contains haemoglobin's which carry oxygen. The muscles needs the oxygen for respiration to release energy to allow the muscles to work and contract more efficenetly, thats why the blood flow rate increases because it tries to match the demand for oxgen required by the muscles.

Thats what I wrote anyway and mentionoing lactic acid for this question is actually quite irrelevant.

(edited 7 years ago)

Reply 452

ewanmennie

I thought for the advantages of using the enzyme you couldn't say it could be reused because the question stated the second enzyme turned it into water?

Reply 453

Kitty141099

Would I get the mark for saying that stem cells are unspecialised rather than undifferentiated?

Reply 454

Sab_1239

Original post by YAY GCSE

Does anyone know if there is a unit 3 unofficial mark scheme? If so please put a link :smile:

http://www.thestudentroom.co.uk/showthread.php?t=4157133

Reply 455

mrtum3000

Original post by Rxkaa

There wasnt a D, it just asked how many pictograms would be in a fertilised embryo, which was 6.6

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This was my order:
1. 6.6 (original amount).
2. 6.6 (after 1st division it has the same genetic info in both cells - chromosomes are replicated).
3. 3.3 (after 2nd division the gametes have 23 chromosomes and therefore half the DNA).
4. 6.6

Reply 456

Chloetbqh

Original post by MahMah

It's not irrelevant because I swear it asked how would it make it easier for the athlete to run lol so it oxidises the lactic acid therefore decreases muscle fatigue causing less discomfort to the athlete

Reply 457

vincentvangogh

7. Meiosis & Mitosis

The sperm cells were produced in the testes by Meiosis. The embryo divided by Mitosis.
For the question about the size of each cell:

6.6

13.2

6.6

3.3

Rest of question is incomplete

For this part, wasn't it:
1. 13.2 (it said the dna duplicated)
2. 6.6 (normal number of dna)
3. 3.3 (gametes)
4. 6.6 (fertilised)

Reply 458

username2626421

Original post by vincentvangogh

For this part, wasn't it:
1. 13.2 (it said the dna duplicated)
2. 6.6 (normal number of dna)
3. 3.3 (gametes)
4. 6.6 (fertilised)

Yeah i got this as my answer

Reply 459

11masanda002

Original post by Zxe

Guys if the question was 'what is meant by anaerobic respiration' and i only put "without oxygen" do you think i could get away with it?

I put the exact same thing and was wondering the same thing. i also put that stored glycogen gets converted into glucose to use as energy to fit the intensity of the exercise