Biology; Chemistry; Physics: Post your doubts here!

[ayeshaK]

we shared the same picture from different links....

Ahan

 

[Spidey21]

Probably ur rite there is never nuf if ur in o'levels S!@t that makes me feel mad....... :-/

nope it shouldnt...thats just gonna make it worse...

 

[Spidey21]

Probably ur rite there is never nuf if ur in o'levels S!@t that makes me feel mad....... :-/

Ahan

http://www.xtremepapers.com/papers/...nal O Level/Biology (5090)/5090_s11_qp_62.pdf
question 3b(i)
how are we supposed to calc the magnification with just one value??

 

[Talhakhan]

U measure the Line which gives the scale 0.05 mm and u will get 27 mm ......... 27/0.05= x540

 

[Spidey21]

U measure the Line which gives the scale 0.05 mm and u will get 27 mm ......... 27/0.05= x540

please do quote next time so the person knows about your message
and why would we do this??

 

[ALI HUSSAIN]

add a drop of water on the slide as a mountant
brush off pollen onto slide
add few drops of methylene blue to stain it
now lower the coverslip at an angle to prevent air bubbles



first heat the non-reducing sugar in HCl..this will break it down to REDUCING SUGAR
then add NaOH to neutralise it
then perform the benedict's test

thankyou veryyyyyyy much...

 

[Nizo]

http://www.xtremepapers.com/papers/CIE/Cambridge IGCSE/Biology (0610)/0610_s10_qp_62.pdf
guyz for question 1 c .... what is trace ??

 

[Spidey21]

http://www.xtremepapers.com/papers/CIE/Cambridge IGCSE/Biology (0610)/0610_s10_qp_62.pdf
guyz for question 1 c .... what is trace ??

trace would mean just a little or very less...

 

[screamingskull]

http://www.xtremepapers.com/papers/CIE/Cambridge IGCSE/Biology (0610)/0610_s10_qp_62.pdf
guyz for question 1 c .... what is trace ??

Trace means slightly present.

 

[Spidey21]

http://www.xtremepapers.com/papers/CIE/Cambridge International O Level/Biology (5090)/5090_s11_qp_62.pdf
question 3b(i)
how are we supposed to calc the magnification with just one value??

Trace means slightly present.

 

[screamingskull]

The scale is given and if you measure the pollen grain it is around 2.9cm=>29mm
so magnification= 29/0.05= x580

 

[Spidey21]

The scale is given and if you measure the pollen grain it is around 2.9cm=>29mm
so magnification= 29/0.05= x580

ok thanx...it was easy :|

 

[Nizo]

thanks !

 

[Talhakhan]

http://www.xtremepapers.com/papers/...onal O Level/Biology (5090)/5090_s03_qp_6.pdf
Help needed with question 3 part c......... Plz give a in depth detail if possible ..... ;-(

 

[Spidey21]

http://www.xtremepapers.com/papers/CIE/Cambridge International O Level/Biology (5090)/5090_s03_qp_6.pdf
Help needed with question 3 part c......... Plz give a in depth detail if possible ..... 8-o

Solution in Visking tubing will have a positive test cuz the starch molecules will be broken down to maltose which will give a postive result to Reducing sugar test but not to starch test...

outside the visking tubing there will be Maltose but no starch as starch cannot leave the visking tubing and thus this will have positive to reducing sugar test and negative to starch test.
hope it helps..

 

[Talhakhan]

Solution in Visking tubing will have a positive test cuz the starch molecules will be broken down to maltose which will give a postive result to Reducing sugar test but not to starch test...

outside the visking tubing there will be Maltose but no starch as starch cannot leave the visking tubing and thus this will have positive to reducing sugar test and negative to starch test.
hope it helps..

I thought i asked Q 3 part c....

 

[Spidey21]

I thought i asked Q 3 part c....

and i thought you asked 2 c...lol
wait..

 

[Spidey21]

I thought i asked Q 3 part c....

well my guess would b that both the distances are directly proportional as when one increases so does the other ..
let me know the answer..

 

[Talhakhan]

well my guess would b that both the distances are directly proportional as when one increases so does the other ..
let me know the answer..

In past paper this answer is written
"the evidence pointed to greater sensitivity in the finger tips. Therefore , there were greater number of receptors in the finger tips. Hence they were closer together and could distinguish the two needles points even when the needlew were most close together..

 

[Spidey21]

In past paper this answer is written
"the evidence pointed to greater sensitivity in the finger tips. Therefore , there were greater number of receptors in the finger tips. Hence they were closer together and could distinguish the two needles points even when the needlew were most close together..

honestly dude..i am not able to get it :|