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Edexcel Biology (Unofficial) B2 Mark Scheme.

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Original post by chelseajabbau
ohhhh right thank you!! i didnt put that :frown: i didnt know it happened in the nucleus so i said the other one about amino acids cuz i thought it breaks down proteins into amino acids


Don't worry its only one mark anyway.
Original post by haybe2k
Edited mark scheme

Spoiler



Edited mark scheme

There's also a question about how Watson and Crick contributed to understanding of the structure of DNA, I believe that was part (c) but can't promise
Original post by keepyourapology
MVP. May I use some answers for the mark scheme?


I absolutely would not mind at all.
Original post by keepyourapology
Anyone remember their answer for the one with the Small Intestine & Bile? The Multipe Choice, I mean.


Ah yes. I remember this question now. The question was on the role of bile in digestion, and the correct answer was to raise pH and neutralise stomach acid. I'm not sure about the neutralising, but I'm sure that it was to raise pH as the pH of stomach acid is 2, and this must be raised to 7 (neutral) before the food is passed through the intestines and more enzymes are added to it.
Original post by ￸￸hi
Ah yes. I remember this question now. The question was on the role of bile in digestion, and the correct answer was to raise pH and neutralise stomach acid. I'm not sure about the neutralising, but I'm sure that it was to raise pH as the pH of stomach acid is 2, and this must be raised to 7 (neutral) before the food is passed through the intestines and more enzymes are added to it.

Yes making conditions alkaline
Reply 245
Original post by bue34 c
Really? so does that mean if you write an answer to a question that is right but isn't on the mark scheme you technically get the marks for it? so does that mean that science oriented examiners will mark our exam? anyway thank you for that you have put my mind at ease.


I don't know if this was a sarcastic response but the post was intended to put those worrying at ease - as you mentioned. However, I understand that the examiners won't be scientists and that you are unlikely to get a mark for a completely incorrect answer but what I meant in my post is that there are OTHER acceptable answers on the mark scheme and examiners credit what is there; they do not deduct marks if it the markscheme answer is not (this is focused particularly on 6-markers).

The "unofficial markschemes" being produced could only be students themselves claiming that their answers are right - not to say that they are wrong - but unofficial markschemes are not always accurate and unless it is a teacher or Edexcel examiner themselves then you can't take their word for gospel. Only results day will tell you how it really went! :biggrin:


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Original post by TheMythicalBeast
Edited mark scheme


There's also a question about how Watson and Crick contributed to understanding of the structure of DNA, I believe that was part (c) but can't promise

The answer to that was that watson and crick created a 3D model of dna using the research of wilkins and franklin, i think you get a mark for also saying x-ray crystalography
Original post by zoeolo
I don't know if this was a sarcastic response but the post was intended to put those worrying at ease - as you mentioned. However, I understand that the examiners won't be scientists and that you are unlikely to get a mark for a completely incorrect answer but what I meant in my post is that there are OTHER acceptable answers on the mark scheme and examiners credit what is there; they do not deduct marks if it the markscheme answer is not (this is focused particularly on 6-markers).

The "unofficial markschemes" being produced could only be students themselves claiming that their answers are right - not to say that they are wrong - but unofficial markschemes are not always accurate and unless it is a teacher or Edexcel examiner themselves then you can't take their word for gospel. Only results day will tell you how it really went! :biggrin:


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Oh sorry if it came off as a sarcastic response, it really was genuine. What you wrote did take away a bit of my stress.
Original post by haybe2k
There's also a question about how Watson and Crick contributed to understanding of the structure of DNA, I believe that was part (c) but can't promise


The answer to that was that watson and crick created a 3D model of dna using the research of wilkins and franklin, i think you get a mark for also saying x-ray crystalography

I put that they created a model showing the bases, I didn't put about what Franklin did because they didn't ask about her. I did mention her and Wilkins, though, kind of as a starter because it was after their work that Crick and Watson created the model.
Original post by TheMythicalBeast
The answer to that was that watson and crick created a 3D model of dna using the research of wilkins and franklin, i think you get a mark for also saying x-ray crystalography


I put that they created a model showing the bases, I didn't put about what Franklin did because they didn't ask about her. I did mention her and Wilkins, though, kind of as a starter because it was after their work that Crick and Watson created the model.

Yh i wrote something similar, I wrote that Watson and Crick built the first 3d structure model of dna that showed specific base pairing, I didn't include anything about Franklin and Wilkins because the question just asked what did Watson and Crick do, Franklin and Wilkins did contribute by shining x ray on crystallised Dna thus finding its structure is a double hellx but that isn't what Watson and Crick did.
Original post by ARK_REVISES
Yh i agree the last question asked you how does water enter into a plant and how does it travel from roots to rest of plant or something like that. I wrote about osmosis via root hair cells then about xylem vessel, not to sure if you had to mention transpiration anyway because its a loss of water it has nothing to do with water entering a plant, albeit it does create a transpiration stream but still i don't think you necessarily needed to include transpiration.


I was petrified by it saying transpiration but when u think back about the question it juz asked how water entered the plants...

Actually transpiration creates the water stream that pulls the water up the xylem vessel and into the leaves, so you need it for the marks
Original post by Michaelmulheran
I was petrified by it saying transpiration but when u think back about the question it juz asked how water entered the plants...


Actually transpiration creates the water stream that pulls the water up the xylem vessel and into the leaves, so you need it for the marks

That's what I thought as well haha. It asked how water got to the leaves not just how it entered. I remember clearly. Transpiration is actually needed in the answer. Oh well they probs got marks somewhere else in the answer!


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Original post by DamnDaniel2
Actually transpiration creates the water stream that pulls the water up the xylem vessel and into the leaves, so you need it for the marks


That's what I thought as well haha. It asked how water got to the leaves not just how it entered. I remember clearly. Transpiration is actually needed in the answer. Oh well they probs got marks somewhere else in the answer!


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I wrote down osmosis, root hair cells and soil, from high water concentation to low water concentration, through partially permeable walls and xylem vessels to rest of the plants. At the end i was going through the answer again so i could pick up more marks, then i thought bout transpiration but i realized transpiration and stuff didn't satisfy the question.

Even though i didnt mention it, im 100% sure i got full marks on that by saying the followings things mentioned above.

When i saw the two six markers i was trembling in joy cos those 2 were easy af... I will get full marks on those but the 2-3 marks questions in fossils and crushed peas, might put me into a high A😭😭😭
(edited 7 years ago)
Original post by ARK_REVISES
That's what I thought as well haha. It asked how water got to the leaves not just how it entered. I remember clearly. Transpiration is actually needed in the answer. Oh well they probs got marks somewhere else in the answer!


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I wrote down osmosis, root hair cells and soil, from high water concentation to low water concentration, through partially permeable walls and xylem vessels to rest of the plants. At the end i was going through the answer again so i could pick up more marks, then i thought bout transpiration but i realized transpiration and stuff didn't satisfy the question.

Even though i didnt mention it, im 100% sure i got full marks on that by saying the followings things mentioned above.

When i saw the two six markers i was trembling in joy cos those 2 were easy af... I will get full marks on those but the 2-3 marks questions in fossils and crushed peas, might put me into a high A😭😭😭

Yh you're likely to get all the marks. Don't worry about it. The grade boundaries (IMO) won't be too high due to the fossil questions and the way some of the questions were worded really weirdly hahaha. There's still hope! Just try and get an A* in B3 for an A* overall!


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Reply 254
Did anyone get 210 for the DNA, Codon question?
Reply 255
Original post by Asfand786
I put down 17, but idk if its right, some people put 18 and some put 15 but it was about an estimate so idk


I got 19 would it count ?


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Reply 256
Original post by bue34 c
i got that but its wrong because after the exam i realised 3 bases/ codon = 1 amino acid thus 620 * 3 not divide


Yeah I did 620 times 3 and got 1890 of something


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Original post by Rof74
I got 19 would it count ?


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Yes as the question said estimate not calculate. I put down 17 but i think it should 16-19/20 to be accepted as the correct answer
Reply 258
Original post by ARK_REVISES
Yes as the question said estimate not calculate. I put down 17 but i think it should 16-19/20 to be accepted as the correct answer


Hopefully. My only problem is that people found a correlation between lactose and sucrose results and applied it to the ph9 and calculated 17, so the only acceptable answer may be 17.


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Reply 259
For the DNA section, Does nayone know the answer about the base/codon question. I got 210 but i'm not sure if thats right?

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