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Yes addition, substitution deletion etc is unit 2


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How many marks was the cytosine drug question worth?


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How many marks was that comparing cytochrome c with haemoglobin question worth? :frown:
the one about the missing amino acid, the introns theory is wrong as all triplet codes will code for an amino acid, thats why you get the degenerate of coding as amino acids are coded for by more than one base triplet
Reply 3984
Didn't think this paper was too bad, some tricky questions though, i really didnt like question 9 on snakes and the Haemoglobin one :s-smilie:

Also, anyone got the specific marking points for the 6 marker? Mine was sort of like this: (i think i got some parts confused)

-water moves into routes by osmosis, high to low water potential
-low wp in roots due to mineral ions
-apoplast/symplastic pathway
-mineral ions actively transported into xylem to create wp gradient??
-water moves viea osmosis from high to low wp from room to xylem
-moves up xylem against gravity
-cohesion tension, H2O molecules 'stuck' together,transpiration causes 'pull' up
-water moves by osmosis into leaves from high to low wp
Is that right/enough for 6 marks do you think?

What does everyone think the grade boundaries are going to be like?

I hope I've done enough to get my A overall
1a(i) Centromere [1]
a(ii) attaches to spindle fibres; and splitting during anaphase [2]
b) different alleles [1]
c) the chromosomes had divided into chromatids [1]
d) Crossing over [1]
2a) groups of organisms; that interbreed to produce fertile offspring [2]
b) 6.98/7;; [2]
c) less plants; less habitat; less food variety [3]
3a) groups within groups; no overlap [2]
b) shows evolutionary relationship [1]
~~~~ 4 marks missing
4a) Sample 1: 15N only;
Sample 2: 14N/15N;
Sample 3: 14N/15N and 14N only [3]
b) breaks H bonds in DNA; between complementary base pairs; unzips the strand [2]
c) binds with guanine; complimentary base pair can’t form; DNA can’t zip back [2]
d) cancer cells as they divide more frequently [1]
5a) vertical gene transmission; passes resistant gene to next generation [2]
b) (The scientists used many patients) to make results more reliable [1]
c) (True) Hypochlorite had most no. of bacteria killed;
(False) SD overlap so no real difference/more likely to be chance; no control dish used; need to test on more disinfectants [3]
d) Mutated; resistant gene; [2]
6a) Quaternary: Haemoglobin only
Condensation: All 3;
Nitrogen: Haemoglobin only [3]
b) least different/most similar amino acids sequence; most similar base pairs; more a.a seq= more closely related [2]
c) B and C had different differences so different amino acid sequences [1]
d) all organisms have it [1]
6a) (Founder effect is when) few/30 individuals from Swiss population colonised a new region; fewer different allele/reduced gene pool; (making it) less genetically diverse; inbreeding; [3]
b) 250,000. [1]
c) mutation; three bases removed [2]
d) amino acid sequence changes; tertiary structure changes; non functional active site, e-s complex can’t form [2]
7a) 16%. [1]
b) (The fetal haemoglobin had) a higher affinity; associates/loads oxygen more readily [2]
The adults haemoglobin was lower affinity so it unloaded easily for respiration. There were no symptoms because they still had adult haemoglobin. Q8 The endodermis actively transported salts into xylem to lower WP so water enters by osmosis causing root pressure. Cohesion tension and transpiration draw water up xylem. The insects moved muscles to ventilate and therefore steepen gradient. The % increase was 342%. The small animals have a large SA:V ratio. There were 6 openings per minute. The removal of water shortened pathway. Q9 The 2 controls were age and species. They used different males so previous tests did not influence results. Random sampling avoided bias. The control was paper with male lipid. The conclusion was that length of female was more influential than lipid. The 2 benefits of longer females were more eggs and better predator. The trend was that males liked high lipid % and the longer the female the higher the lipid %. To find missing value extend line of best fit and extrapolate, however we cannot predict intermediate values so these are not accurate. The males would not recognise the other species.


NB: credit to @Semanresu . will update rest with marks later
Can someone tell me on what page the unofficial markscheme is?
Original post by VigneshSB
Because, my fricking 'Uncle who is a doctor' has a ****ing pHD in Oncology bitch; Stop acting smart


hey hey no need to get your knickers in a twist young boy!


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Original post by laym
Didn't think this paper was too bad, some tricky questions though, i really didnt like question 9 on snakes and the Haemoglobin one :s-smilie:

Also, anyone got the specific marking points for the 6 marker? Mine was sort of like this: (i think i got some parts confused)

-water moves into routes by osmosis, high to low water potential
-low wp in roots due to mineral ions
-apoplast/symplastic pathway
-mineral ions actively transported into xylem to create wp gradient??
-water moves viea osmosis from high to low wp from room to xylem
-moves up xylem against gravity
-cohesion tension, H2O molecules 'stuck' together,transpiration causes 'pull' up
-water moves by osmosis into leaves from high to low wp
Is that right/enough for 6 marks do you think?

What does everyone think the grade boundaries are going to be like?

I hope I've done enough to get my A overall


Did you mention anything about negative pressure?
Looll sorry just saw it :smile:
guys have we got a proper unofficial markscheme??
Reply 3991
We got taught addition, deletion and substitution for unit 2 in class. I think you'll get credited for either, it was more about how it results in a non functional protein as amino acid sequence changes :smile:
Reply 3992
Original post by chelley2
What happened to;
tissue fluid ,DNA hybridisation ,blood vessels and the other half of the spec.If I get anything higher than D it's a miracle


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there wasn't anything on stages of mitosis. Or fish :frown: Oh man
Reply 3993
Original post by VigneshSB
Because, my fricking 'Uncle who is a doctor' has a ****ing pHD in Oncology bitch; Stop acting smart


children, calm your tits, you must
Reply 3994
Original post by massi1296
the one about the missing amino acid, the introns theory is wrong as all triplet codes will code for an amino acid, thats why you get the degenerate of coding as amino acids are coded for by more than one base triplet


Has anyone got the paper with the actual question?
Original post by Shaadi Baba
hey hey no need to get your knickers in a twist young boy!


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:wink: Haha! Was just kidding amigo! But yeah, what he said was true though, no frame shift occurs :smile:
so will i not get anymarks for talking about apoplast etc only
Reply 3997
Original post by The_Blade
so will i not get anymarks for talking about apoplast etc only


Nope thats from the epidermis to endodermis, it was asking from endodermis to xylem to leaves. If you did mention it you wont get penalised but wont get any marks either.
What was the answer to the question about spiracles and the graph. We had to find the rate of openings from the graph or something like that?
Reply 3999
Original post by lorobolorolo
What was the answer to the question about spiracles and the graph. We had to find the rate of openings from the graph or something like that?


If you looked through this thread, about 50 people have said the answer. It is 6.