A2 Biology | Post your doubts here

[hassam]

wat kind of graph is this

 

[hassam]

http://www.xtremepapers.com/papers/...nd AS Level/Biology (9700)/9700_w09_qp_52.pdf
i cant undrstand q1...part b........they only showed graph at day 3 for control.....and........watrs happening here

 

[hassam]

cn we say here that in CC nutrient conc is kept constant throughout so its not a variable...bt in batch rate will decrease due to nutrient conc. falling
plus i dont get this that how s.d is realted to reliability....cud smone make it clear by quoting an example please

 

[princesskt]

http://www.xtremepapers.com/papers/CIE/Cambridge International A and AS Level/Biology (9700)/9700_w09_qp_52.pdf
i cant undrstand q1...part b........they only showed graph at day 3 for control.....and........watrs happening here

day 3 is time when they start taking results and control would only be the one at the start of the exp.that shows %cell survival with no immobilized cells.....means the normal %.....
thats what we do when we suggest a control...........

 

[hassam]

http://www.xtremepapers.com/papers/...nd AS Level/Biology (9700)/9700_w11_qp_51.pdf
q2 a why ms doesnt allow volume of culture medium....cos i think nutrient cconc shud be kept constant bt ms says only composition

 

[hassam]

http://www.xtremepapers.com/papers/...nd AS Level/Biology (9700)/9700_w11_qp_53.pdf
q1 b (i)i dun understand @ keeps organelles intact.................................even if i dont add buffer why wud even the pH CHANGE

 

[hassam]

http://www.xtremepapers.com/papers/...nd AS Level/Biology (9700)/9700_w11_ms_53.pdf
q1 plan part.....does amount of sample even matters for chromatography....i mean y we want samen mass.......it shudnt make any difference the other way

 

[hassam]

done the papers from 2009 to 2011 .....still not satsifed......1st 3 papers i.e 2007 and 8 ones were hell easy...........knw any other source for practice??

 

[user]

wat kind of graph is this

log graph...when u take log of the values shown...u'd get it

 

[princesskt]

done the papers from 2009 to 2011 .....still not satsifed......1st 3 papers i.e 2007 and 8 ones were hell easy...........knw any other source for practice??

YEAH ME TOO DONE WITH THESE PAPERS BUT NOT SATISSFIED............WHAT TO DO KNOW...........
HOPE OUR PAPER COMES EASY................

 

[smartangel]

http://www.xtremepapers.com/papers/...nd AS Level/Biology (9700)/9700_w11_qp_53.pdf
Q2..b ii..where do we get expected value from??

 

[princesskt]

http://www.xtremepapers.com/papers/CIE/Cambridge International A and AS Level/Biology (9700)/9700_w11_qp_51.pdf
q2 a why ms doesnt allow volume of culture medium....cos i think nutrient cconc shud be kept constant bt ms says only composition

IN A CONTINOUS CULTURE ther eis a continous supply of nutrients and products removed,difficult to maintain same volume so its composition must be the same throuhout or we can say i think the concentration but it contains a mixture so composition better..........

 

[smartangel]

http://www.xtremepapers.com/papers/...nd AS Level/Biology (9700)/9700_w11_qp_52.pdf
Q1 b..plz explain both parts...

 

[princesskt]

http://www.xtremepapers.com/papers/CIE/Cambridge International A and AS Level/Biology (9700)/9700_w11_qp_53.pdf
Q2..b ii..where do we get expected value from??

from a cross
eg wth out tail symbol A EARLIER SAID WTHOUT TAIL HETRO
Aa *Aa
AA Aa Aa aa
3/4: 1/4
3/4*(72+40) 1/4 *(72+40)
hope it helpssssssssssssss,....................

 

[smartangel]

from a cross
eg wth out tail symbol A EARLIER SAID WTHOUT TAIL HETRO
Aa *Aa
AA Aa Aa aa
3/4: 1/4
3/4*(72+40) 1/4 *(72+40)
hope it helpssssssssssssss,....................

dont get it

 

[smartangel]

http://www.xtremepapers.com/papers/...nd AS Level/Biology (9700)/9700_w11_qp_52.pdf
Q2d..again how do we get expected valuee???

 

[smartangel]

All those done with pastpaers plzz help me out...

 

[smartangel]

also in chi square test if our probability comes out to be greater than 0.05 then its due to chance..what abt t-test??

 

[hassam]

also in chi square test if our probability comes out to be greater than 0.05 then its due to chance..what abt t-test??

the probaillity we are talking abt here is probability of null hypothesis being correct......so if its less than 0.05 Null hpotheis is rejected,....and so on...........this 0.05 level is actuallyy 95 PERECENT PROBABILITY THAT NULL HYPOTHESIS IS CORRECT BT DONT KNW HOW,,,,,,SOME frther maths shud be ale to explain this 95 percent thing

 

[ying27kia]

also in chi square test if our probability comes out to be greater than 0.05 then its due to chance..what abt t-test??

It's the same. 0.05 act as decider for both chi square test and t-test.
if probability is greater than 0.05 it means null hypothesis is correct.