A2 Biology | Post your doubts here

[smartangel]

http://www.xtremepapers.com/papers/...and AS Level/Biology (9700)/9700_s08_ms_5.pdf
Q2 a ii...what happnd to their graph? at the beginning :/

 

[MysteRyGiRl]

well@user cn u amke a sticky thread for BIO PAPER 5
Mystery girl......why they are not allowing 3 dp for that question,,,,i gave two 3 s.f tand that was automatically to 3dp in dat case.....

hassam why have they written zero mark for da 0.68 answer??? it should be 0.67?

 

[MysteRyGiRl]

http://www.xtremepapers.com/papers/...and AS Level/Biology (9700)/9700_w08_qp_5.pdf
plzzzzzzz help needed in part b iv) i dont get how we got da answer

 

[MysteRyGiRl]

http://www.xtremepapers.com/papers/CIE/Cambridge International A and AS Level/Biology (9700)/9700_w08_qp_5.pdf
plzzzzzzz help needed in part b iv) i dont get how we got da answer

oh sory i got it

 

[ousamah112]

http://www.xtremepapers.com/papers/CIE/Cambridge International A and AS Level/Biology (9700)/9700_s08_ms_5.pdf
Q2 a ii...what happnd to their graph? at the beginning :/

yeah.. it shuld be smooth curve at the beginning..

 

[hassam]

http://www.xtremepapers.com/papers/...nd AS Level/Biology (9700)/9700_s11_qp_51.pdf
in question 1 plan part....why it says same mass of potato each tym.....if we are calculating percentage change in mass it doesn't matters.........isnt it

 

[hassam]

i cat understand t test......though i knw how to use it and how to cum to cnclusion......bt i have sum cnfusions.....well wat are these t values......i mean wat they represent........and wats the link of 0.05 significance level with 95 percent

 

[hassam]

http://www.xtremepapers.com/papers/CIE/Cambridge International A and AS Level/Biology (9700)/9700_w10_qp_51.pdf
q1 independent variable:
1. ref. to a systematic way of obtaining leaves;
e.g.
3rd leaf from the apex / different heights / all from
the same height / equal light exposure
now WTH he means here......why different heights and then immediately after all the same height.....for same light exposure it must be all from the same heigght,....and one more leaves must be from same plant
in the same question .........why we want to measure dry mass???

 

[princesskt]

http://www.xtremepapers.com/papers/CIE/Cambridge International A and AS Level/Biology (9700)/9700_w10_qp_51.pdf
q1 independent variable:
1. ref. to a systematic way of obtaining leaves;
e.g.
3rd leaf from the apex / different heights / all from
the same height / equal light exposure
now WTH he means here......why different heights and then immediately after all the same height.....for same light exposure it must be all from the same heigght,....and one more leaves must be from same plant
in the same question .........why we want to measure dry mass???

me too didnt understood why to take dry mass here......

 

[princesskt]

http://www.xtremepapers.com/papers/...nd AS Level/Biology (9700)/9700_w09_ms_51.pdf
is the graph correct...........temp one,

 

[angelgirl:)]

we can use this thread for ppr 5 as well ? or therez diff thread for p5 bio?

 

[hassam]

this one

 

[hassam]

and guyx plxx do discuus....its scaring me Paper 5 and nobody is interested in it

 

[hassam]

http://www.xtremepapers.com/papers/CIE/Cambridge International A and AS Level/Biology (9700)/9700_w09_ms_51.pdf
is the graph correct...........temp one,

yea cos at higher temp photosystem myt get damged

 

[angelgirl:)]

http://www.xtremepapers.com/papers/CIE/Cambridge International A and AS Level/Biology (9700)/9700_w10_qp_51.pdf
q1 independent variable:
1. ref. to a systematic way of obtaining leaves;
e.g.
3rd leaf from the apex / different heights / all from
the same height / equal light exposure
now WTH he means here......why different heights and then immediately after all the same height.....for same light exposure it must be all from the same heigght,....and one more leaves must be from same plant
in the same question .........why we want to measure dry mass???

me too didnt understood why to take dry mass here......

since we r investigating indirectly the rate of photosynthesis with the light intensity...we have to concider the dry mass that how much mass was increased or decreasd due to light intensity...if we dont consider the dry mass then the exp. will be wrong as even the water potential will play a roll for change in mass...coz at high light intensity the leaf will be having less water potential due to high rate of transpiration and
viceversa...

 

[hassam]

http://www.xtremepapers.com/papers/...nd AS Level/Biology (9700)/9700_w10_qp_53.pdf
q1 c (ii) i cnt understand how s.d shows reliablity of our results

 

[hassam]

since we r investigating the rate of photosynthesis with the light intensity...we have to conciider the dry mass that how much mass was increased or decreasd due to light intensity...if we dont consider the dry mass then the exp. will be rong as even the water potential will play a roll for change in mass...coz at high light intencity the leaf will be having less water potential due to high rate of transpiration and
viceversa...

NO WE R NOT investiggating rate of PHOTOSYNTHESIS ANYWHERE!!!

 

[angelgirl:)]

http://www.xtremepapers.com/papers/CIE/Cambridge International A and AS Level/Biology (9700)/9700_w10_qp_51.pdf
q1 independent variable:
1. ref. to a systematic way of obtaining leaves;
e.g.
3rd leaf from the apex / different heights / all from
the same height / equal light exposure
now WTH he means here......why different heights and then immediately after all the same height.....for same light exposure it must be all from the same heigght,....and one more leaves must be from same plant
in the same question .........why we want to measure dry mass???

as we r experimenting for 2 diff. light intensity, 1 for shaded and 1 for exposre to light...so either we r using 1 pot for both light intensity , that is half the plant is exposed to light and half to darkness...or 2 pots of the same species of plant with the same no. of leaves....
so here they meant that for each exp. take the leaf from diff. height but it should start 3rd leaf from the epix as epex is the growing shoot so thay will use the product of photosynthesis for cell elongation rather than for storage so u cant calculate the change in mass..and for both the experiment , u should use the same height...thats wat i understood...dont know wether iam corrct or not?

 

[angelgirl:)]

NO WE R NOT investiggating rate of PHOTOSYNTHESIS ANYWHERE!!!

then how the dry mass changes? and den y u r exposing it to light intensity? change in mass means indirectly we have to consider rate of photosyanthesis...and the factors affecting its rate...
hassam

 

[hassam]

then how the dry mass changes? and den y u r exposing it to light intensity? change in mass means indirectly we have to consider rate of photosyanthesis...and the factors affecting its rate...
hassam

where is change in mass??? its written mean mass of leaves