Biology paper 62

[whitetiger64]

can any one plss post foods and thier tests with observations

thanks in advance

Food tests:
Starch:
Iodine, observe a colour change from brown to blue-black.

Reducing Sugars:
Cut or grind off a small sample and add it to water to attempt to dissolve it. Then add Benedict's solution and heat using a waterbath. Observe a colour change from blue to brick-red.

Protein:
Cut or grind off a small sample and add to biuret solution. Observe a colour change from blue to purple.

Fat:
Cut or grind off a small portion. Place in a test tube of ethanol and shake. Add the liquid part of this mixture to a test tube containing water. Observe a cloudy emulsifying change.

 

[Gimmick]

no units, ryt?

Yes, there are no units for magnification.

 

[IGCSE O/L student]

hey do u think nitrogen/water cycle r imprtnt fr dis ppr?

no, i dnt think so

 

[whitetiger64]

Hey I need help.. http://www.xtremepapers.com/papers/CIE/Cambridge IGCSE/Biology (0610)/0610_w11_ms_61.pdf
Qn 2 (b).. How on earth do I find the surface area?? Please help!!

count the squares where the feathere occupies more than half of the square.....i think

 

[salvatore]

count the squares where the feathere occupies more than half of the square.....i think

Thanks for ur reply..
Then what?? Lyk jus count the squres??

 

[whitetiger64]

Thanks for ur reply..
Then what?? Lyk jus count the squres??

yeah dt wud be da surface area!

 

[shafayat]

WHAT IS cladistics (based on RNA/
DNA sequencing data)???
I SAW IT ON THE SYLLABUS BUT I NEVER TOOK IT!

u dont have to now wht it is ... u onli have to know that bionomial system is not the onli system of classification there are many others

 

[shafayat]

you could contact me through my xtremepapers inbox if you like; I wouldn't mind giving some hints on the condition of the exam, haha you're taking variant 62?

i'm doin variant 1 2morrow.

my exam starts 12 pm india time which is 1:30 indonesia.....may i know ur email please?

guysss wht time r u writting ur exams ..!! I am writiing on 7:30-9:30 am UAE time
if any of u doin it b4 me .. PLEASE i beg for help !!

 

[whitetiger64]

hey ppl cn any1 plz tell me wts a buffer???

 

[ZainH]

hey do u think nitrogen/water cycle r imprtnt fr dis ppr?

Hope not, I'm terrible at the nitrogen cycle.

hey ppl cn any1 plz tell me wts a buffer???

A buffer basically is used to vary the pH in a solution. There are different buffers you can add to solutions to change there pH.

 

[whitetiger64]

Hope not, I'm terrible at the nitrogen cycle.



A buffer basically is used to vary the pH in a solution. There are different buffers you can add to solutions to change there pH.

kk tnx

 

[whitetiger64]

http://www.xtremepapers.com/papers/CIE/Cambridge IGCSE/Biology (0610)/0610_s10_qp_61.pdf
question 3 a) ii.....cn sum1 plz explain hw to calculate?

 

[ZainH]

http://www.xtremepapers.com/papers/CIE/Cambridge IGCSE/Biology (0610)/0610_s10_qp_61.pdf
question 3 a) ii.....cn sum1 plz explain hw to calculate?

Well in dish B there are 20 seeds out of which 2 germinated . In dish C there are 10 seeds out of which 9 germinated .
So there asking if there were 20 seeds in dish C how many would germinate? You could either use cross multiplication or common sense to know that if 9 out of 10 germinated , then 18 out of 20 would germinate. Then you calculate the percentage increase of 2/20 seeds that germinated in dish B compared to the 18/20 seeds that would germinate in dish C.

2/20 = 0.1
18/20 = 0.9

0.1= 100%
0.9 = ?

0.9x100/0.1 = %900

I think that's the answer.

 

[whitetiger64]

Well in dish B there are 20 seeds out of which 2 germinated . In dish C there are 10 seeds out of which 9 germinated .
So there asking if there were 20 seeds in dish C how many would germinate? You could either use cross multiplication or common sense to know that if 9 out of 10 germinated , then 18 out of 20 would germinate. Then you calculate the percentage increase of 2/20 seeds that germinated in dish B compared to the 18/20 seeds that would germinate in dish C.

2/20 = 0.1
18/20 = 0.9

0.1= 100%
0.9 = ?

0.9x100/0.1 = %900

I think that's the answer.

thnx sooo much!!!

 

[ZainH]

thnx sooo much!!!

Your welcome.. but the mark scheme says 800% .. What the hell?
Sec.. I need to see what they did :S

 

[ZainH]

thnx sooo much!!!

Haaa okay. There asking for percentage INCREASE. So you have to calculate the difference in GERMINATING seeds in both dishes.

18-2 = 16

Then just calculate the same way..

2 = 100%
16 = ?

16x100/2 = 800%

 

[whitetiger64]

Haaa okay. There asking for percentage INCREASE. So you have to calculate the difference in GERMINATING seeds in both dishes.

18-2 = 16

Then just calculate the same way..

2 = 100%
16 = ?

16x100/2 = 800%

oook....it makes snse nw! thnx

 

[ZainH]

oook....it makes snse nw! thnx

Lol anytime x)

 

[salvatore]

Guys pleaseeeee help.. I asked a question but no one has replied yet.. How do you find the surface area of a leaf on a grid??
http://www.xtremepapers.com/papers/CIE/Cambridge IGCSE/Biology (0610)/0610_w11_qp_61.pdf No. 2(b)
Please show me the working..!!

 

[omar1999]

Guys pleaseeeee help.. I asked a question but no one has replied yet.. How do you find the surface area of a leaf on a grid??
http://www.xtremepapers.com/papers/CIE/Cambridge IGCSE/Biology (0610)/0610_w11_qp_61.pdf No. 2(b)
Please show me the working..!!

first count the number of all boxes in the diagram ( for example there is 8 rows and 4 columns then multiply them the answer is 32 ) then count the number of the boxes that are more than half empty and then subtract the answer from the whole number which is 32 (for example there is 10 boxes more than half empty so the surface area of the leaf is 32-10= 22 cm squared )