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A level Biology: Post your doubts here!

areebaization

areebaization

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joanna omar said:
Anyone please I've got some doubts over here !

Nov 2011 v2 -----> Q16
june 2012 v2 ----->Q27
Nov 2012 v2-----> Q17 and Q38
Nov 2012 v3 ----->Q39

HELP !
Nov 2013 v1/3

Q1 , 7 , 8 and 17 ?

http://server-poddarh.rhcloud.com/paper.html
ZaqZainab

areebaization
Click to expand...
Q16 Thats because cholestrol controls fluidity of the cell.

Q27 You just have to learn the position of xylem and phloem, what I do is, I just remember the position of xylem (It gives support so it should be in the middle with the exception alignment in the leaf) the other one has to be phloem!

Q38 X die, more producers for primary consumers, and more food for B as they feed on the 1* consumers
 
joanna omar

joanna omar

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ZaqZainab said:
Nov 2011 v2 -----> Q16 As temperature decreases(getting colder) the membrane gets less fluid
less fluid means more the unsaturated bonds
and so unsaturated increasing and saturated decrease
june 2012 v2 ----->Q27 all of them are tiny enough to leak from blood to the lymph and all of them are present in the tissue fluid too
Nov 2012 v2-----> Q17 and Q38 q17 what do they mean by an equilibrium? means equal no of molecules on both sides
Diffusion ----> you perfume in a corner of a room at the end of the day you will be able to smell the odor all over the room
Osmosis------> add a drop of color to water in a corner after a while you will see all of the water is colourised
Facilitated diffusion---> same thing as diffusion just with bigger molecules
Active transport--> from lower to higher this is trying to oppose the equilibrium
Q38 if you remove X the primary producer will have 1 less animal feeding on it means it will be more in number
and D will have 1 less animal to feed on D will decrease now A has 1 less animal to eat from but it still has B so it will eat more of B and so A B D are decreasing
where as C increases as it gets most of the food as B is no more there
Nov 2012 v3 ----->Q39 Even idk :(

Nov 2013 v1/3

Q1 , 7 , 8 and 17 ? which variant?
Click to expand...


Nov 2013 .....var 3

Thanks alotttt !!! May allah help you like u did ameen ....inshallah you Ace exams
 
ZaqZainab

ZaqZainab

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joanna omar said:
Nov 2013 .....var 3

Thanks alotttt !!! May allah help you like u did ameen ....inshallah you Ace exams
Click to expand...
Nov 2013 .....var 3
Q1 In mitochondria, the cristae help in ATP Synthesis. They are the inner folded structures in the mitochondria, which increases the total surface area of the inner membrane.
Q7 1- i guess thats obvious haem group has iron in it which helps the transport of oxygen by combining to it
2- so that you can use the same hemoglobin molecule again and so suitable
3- when it changes shape it makes it easier to load another oxygen on to it
Q8 sorry idk this one either
Q17 1 cannot be the answer eliminate all the options which contain 1 you are left with D
I hope i am of any help to you just remember me in your prayers
 
areebaization

areebaization

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areebaization

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DeViL gURl B)

DeViL gURl B)

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areebaization said:
I really have a strong feeling that the ms is wrong this time.
The hydrogen bond per each base pair can either be 2( Adenine pairing with Thymine) or 3( Guanine pairing with Uracil).
Since they said MAXIMUM, we assume that all the bases had triple bond.
So,
1 base pair------>3bonds
700 base pair=700*3=2100 bonds
Click to expand...
That's exactly my feelin as well.. But there is a bit twist in the question,,which left me thinkin.
The previous question mentioned had the answer 2100 but it was 700 base pairs..
This one says 700 nucleotides ...
 
Karim Nabil

Karim Nabil

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Snowysangel said:
But you just said that the bronchus is involved in gaseous exchange...that's why they're inner membrane is folded to allow expansion :S also don't the antibodies attach to the mast cell AFTER encountering a pathogen (the antigen would've have bonded to them to make that happen)
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infolded to allow expansion for increasing S.A not for gaseous exchange
yes to increase inflammation and make mast cells release histamine to attract nearby neutrophils.
 
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