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Edexcel Biology (Unofficial) B2 Mark Scheme.

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Reply 80
Avatar for bue34 c
bue34 c
5
how was the multi choice question about the food going from stomach to small intestine true? because food is absorbed into small intestine through the bloodstream and not directly from the stomach
Original post by shania.d.f
A codon has three bases and one codon makes up one amino acid. So, it would make sense to do 630*3. Honestly, I think they just said minimum to confuse students.

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I think you're right about them confusing people - at first I started dividing because it said 'minimum' which makes you think it will be smaller. But then I realised and did 630 x 3 to get 1890. 😅
Original post by bue34 c
how was the multi choice question about the food going from stomach to small intestine true? because food is absorbed into small intestine through the bloodstream and not directly from the stomach


You have got it the wrong way round. Food is absorbed into the blood from the small intestine - not the other way round. So, food goes into the small intestine from the stomach and is then absorbed into the blood through the villi.
Reply 83
Avatar for htkta
htkta
8
What did everyone put for that question about embryos and specialised cells?
Reply 84
Avatar for bue34 c
bue34 c
5
Original post by ca.hardy
You have got it the wrong way round. Food is absorbed into the blood from the small intestine - not the other way round. So, food goes into the small intestine from the stomach and is then absorbed into the blood through the villi.


Oh thanks, damn it stupid mistakes
Reply 85
Avatar for Alasama
Alasama
Yeah, you had to times 630 by 3
Reply 86
Avatar for bue34 c
bue34 c
5
Original post by htkta
What did everyone put for that question about embryos and specialised cells?


I said through differentiation after the 16 cell stage
Reply 87
Avatar for htkta
htkta
8
Original post by bue34 c
Oh thanks, damn it stupid mistakes


Don't worry, I think edexcel purposefully wanted to trick students based on some of the questions on that paper. I think the boundaries will be reasonable, hopefully anyway.
Reply 88
Avatar for htkta
htkta
8
Original post by bue34 c
I said through differentiation after the 16 cell stage


Yeah, I mentioned differentiation too. But I also talked about embryonic stem cells?
Reply 89
Avatar for bue34 c
bue34 c
5
Original post by htkta
Yeah, I mentioned differentiation too. But I also talked about embryonic stem cells?


Yh thats sounds right, what did you put for the question that asked you to explain the differences in the tubes? i referred to the ph but not entirely sure if thats right
Reply 90
Avatar for htkta
htkta
8
Original post by bue34 c
Yh thats sounds right, what did you put for the question that asked you to explain the differences in the tubes? i referred to the ph but not entirely sure if thats right


Which question was that?
Reply 91
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bue34 c
5
Original post by htkta
Which question was that?


i think it was with the yeast experiment question
Reply 92
Avatar for htkta
htkta
8
Original post by bue34 c
i think it was with the yeast experiment question


I have no idea. I can't remember what I put, but I remember I used the figures on the table and made something up!!
Original post by keepyourapology
17, cuz it should have been less than the other two. I put 20 but Idk who's right.


Its 42 because the table showed that as the pH decreased by 2, the (whatever it was) increased by 7 (I think it was 7). So it looked like this:

pH: Sugar: (Whatever it was)
9. fructose. 28
7. fructose. 35
5. fructose 42. ----> this is the answer you should have got - the question was testing our ability to notice trends.
Reply 94
Avatar for bue34 c
bue34 c
5
Original post by htkta
I have no idea. I can't remember what I put, but I remember I used the figures on the table and made something up!!



Oh ok
If people can give me the questions and your answers i will help aswell.

Question 1 (Bacterial/Yeast Cell) :
Part (a):(yeast cell)• has a nucleus (1)• does not have a flagellum(1)• does not have a plasmid(1)• has a vacuole(1)(bacterial cell)• has chromosomal DNA /circular DNA (1)• has a capsule (1)• has a slime coat (1)• does not have mitochondria (1)
Part b : where does respiration take place in the yeast : Mitochondria.
Part (?):17 ( pH 9 decreases the concentration )

Question 2 (Digestion):
Part (a):Peristalsis
Part(b): No villi / Surface area of one cell / ...
Part (c):The amylase in the saliva will break down the starch present in the bread to form sucrose.

Fossils Question :
Part(a) :D
Part (b):
Human Intervention
Loss of habitat
Climate Change
Predators (correlate to increase in group B&C)

DNA Extraction:
Part(a):
Part(b): Break up the cells to help the dna releasing from the nucleus ( Not Protease )
Part(c):
Part(d):
Differences between mitosis & meiosis:
Haploid cells vs Diploid Cells (1)
Genetically Varied vs Genetically Identical (1)
4 Daughter Cells vs 2 Daughter Cells (1)
Gametes vs Body Cells
Circulatory System:
Part(a):Pulmonary Vein
Part(b):De-oxygenated blood moves into the right atrium via the vena cava, moves to the right ventricle through the valves, and goes to the lungs via the pulmonary artery.
Part(c):
Part(d):Six marker on how the narrowing of coronary arteries affect the functioning of the heart and surrounding body cells.
- Increased pressure - Heart and body cells have slower respiration rate - Heart problems such as cardiac arrest leading to coma - Fatigue in exercise - Smaller cardiac output

Leaves:
Part(a):
Part(b):
Part(c):Light is no longer the limiting factor, and hence, increasing the amount of light intensity will not affect rate of reaction, as some other factor is in shorter supply and is controlling the rate.
Part (d):Six marker on movement of water in a plant. Transpiration , Osmosis through roots , water vapour entering the stomata through diffusion
(edited 7 years ago)
Original post by ca.hardy
Its 42 because the table showed that as the pH decreased by 2, the (whatever it was) increased by 7 (I think it was 7). So it looked like this:

pH: Sugar: (Whatever it was)
9. fructose. 28
7. fructose. 35
5. fructose 42. ----> this is the answer you should have got - the question was testing our ability to notice trends.


Except if you looked above at the...sucrose, I think it was, you would see that the fructose answer for pH value x was always the x value for the sucrose divided by 13 to 13.2 (I believe). Using this - which uses trends and acknowledges the proportional relation of the sucrose value to the fructose value - the answer would have been 17.

[EDIT: read ahead; I think you may be right now based on question wording. Now I think of it though, how can you notice a trend from just two values? I think the question inherently asked us to see the relationship between fructose and sucrose, not the pH trend of fructose alone.]
(edited 7 years ago)
Reply 97
Avatar for htkta
htkta
8
Original post by Southwestern
Except if you looked above at the...sucrose, I think it was, you would see that the fructose answer for pH value x was always the x value for the sucrose divided by 13 to 13.2 (I believe). Using this - which uses trends and acknowledges the proportional relation of the sucrose value to the fructose value - the answer would have been 17.


Didn't think they'd include a trend this intricate in a biology exam :s-smilie:
Original post by htkta
Didn't think they'd include a trend this intricate in a biology exam :s-smilie:


I agree: the "n+7" trend argued by @ca.hardy seems much more fitting :smile:
Reply 99
Avatar for htkta
htkta
8
Original post by Southwestern
I agree: the "n+7" trend argued by @ca.hardy seems much more fitting :smile:


Who knows. This is all conspiracy, for all we know neither answers could be correct! Sometimes mark schemes are a little lenient.

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