A2 Biology | Post your doubts here

[Sara200]

http://www.xtremepapers.com/papers/...nd AS Level/Biology (9700)/9700_w11_qp_53.pdf
Q2 B(ii) how do we find E?

 

[XPFMember]

AsSalamoAlaikum Wr Wb!

What's meant by booster vaccination?

 

[hassam]

http://www.xtremepapers.com/papers/...and AS Level/Biology (9700)/9700_w07_qp_5.pdf
q 3 a (ii) confused.......if there are 114 moths in ungrazed land......there no. shud decrease bt according to null hypotheis it shud remain at 114.........dont knw wat ms means...when it says to add up the numbers and divide by 3.........cn any 1 address my cnfusion

 

[Nibz]

AsSalamoAlaikum Wr Wb!

What's meant by booster vaccination?

Normal vaccines stimulate primary immune response, but booster vaccines stimulate the secondary immune response resulting in a larger clone at a faster rate.

 

[ony]

how do u calculate the rate of reaction of enzyme reaction?
final time given and final volume given, no initial rate of reaction.

 

[ying27kia]

http://www.xtremepapers.com/papers/CIE/Cambridge International A and AS Level/Biology (9700)/9700_w11_qp_53.pdf
Q2 B(ii) how do we find E?

do a monohybrid cross. you'll find it from the ratio

 

[ying27kia]

how do u calculate the rate of reaction of enzyme reaction?
final time given and final volume given, no initial rate of reaction.

There are many ways to find the rate of reaction.
one method is by keeping one variable i.e. volume constant.
rate is proportional to 1/time taken to collect the volume.
Am I answering ur question?

 

[usmiunique]

http://www.xtremepapers.com/papers/...and AS Level/Biology (9700)/9700_w07_qp_5.pdf
q 3 a (ii) confused.......if there are 114 moths in ungrazed land......there no. shud decrease bt according to null hypotheis it shud remain at 114.........dont knw wat ms means...when it says to add up the numbers and divide by 3.........cn any 1 address my cnfusion

The null hypothesis in this case is that there is no significant difference between the no of moths in grazed and ungraded land.. Meaning that the number of moths should be equal in in all fields.. This is 36+90+114/3=80 which is the expected number of moths in BOTH grazed and ungraded land!

 

[usmiunique]

how do u calculate the rate of reaction of enzyme reaction?
final time given and final volume given, no initial rate of reaction.

Maybe it should be (final volume-initial volume)/time taken

 

[hassam]

The null hypothesis in this case is that there is no significant difference between the no of moths in grazed and ungraded land.. Meaning that the number of moths should be equal in in all fields.. This is 36+90+114/3=80 which is the expected number of moths in BOTH grazed and ungraded land!

hmm...........still some doubt

 

[Tasneem Mahmood Chowdhury]

I need help in paper5...plzz can u help me???can any one help me???plzz me understand the t-test thingy....

 

[vita199]

can anyone tell the me some experiments that i should know for the exam and predict any design experiment that is likely to come this time for 52???t

 

[MysteRyGiRl]

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

s.d is da spread of data around da mean value...meaning if s.d is high,there is more error in da values so less acurate and vice versa...hope its clear

 

[princesskt]

can any one tell me what is meant by that two genes are on seperate chromosomes?????

 

[MysteRyGiRl]

can any one tell me what is meant by that two genes are on seperate chromosomes?????

well chromosomes are structures of DNA containing many genes,so it myt be 2 same genes are on 2 different chromosomes...can u elaborate ur question a bit?

 

[MysteRyGiRl]

can any1 explain da meaning of 'overlap of 2 sets of data'?

 

[angelgirl:)]

can any1 explain da meaning of 'overlap of 2 sets of data'?

i guess u r talking about the overlapping of the error bars...isnt it?
if its so...then if the error bars of the 2 sample overlaps,it means the 2 means of the 2 samples
---r not significantly different...
---its by chance..
---the 2 samples r kind of identicle to eachother...
---there is no relation b/w there differences...
---u cant do anything to the method u carried out to make it more better as its just by chance....
---the value will be 5% or > 5%...
---the null hypothesis is proved correct...
hope i explained it correctly

 

[MysteRyGiRl]

ok could u plz explain a bit about null hypothesis?? evry1 here is giving diferent opinions

 

[MysteRyGiRl]

http://www.xtremepapers.com/papers/...and AS Level/Biology (9700)/9700_s09_qp_5.pdf
plz explain where da hell we got 38 from in Q no 3 iv)

 

[MysteRyGiRl]

angelgirl:) u left?