Biology; Chemistry; Physics: Post your doubts here!

[luckywang]

u shud kno the definition, whether the daughter cells are genetically identical or not, no. of daughter cells produced by each division of mitosis or meiosis and then the roles of mitosis n meiosis.

one question just pop out from my mind after read ur reply... mitosis produce two identical daughter cell and meiosis produce 4 haploid gamete?

 

[malay]

one question just pop out from my mind after read ur reply... mitosis produce two identical daughter cell and meiosis produce 4 haploid gamete?

yeah correct!

 

[kitecrystal]

what are the functions of nitrifying,denitrifying,nitrogen fixing and decay bacteria?

 

[luckywang]

question again! is blood cotting included in our syllabus? i mean the detail one, like what enzyme convert what to what and something like that... syllabus didnt mention the detail of blood clotting? we need to know the outline or detail process? becoming questioning kid...

help me on this?

 

[luckywang]

if it asked to explain why there is no net movement of CO2 then how?​

these are my answer:​

1)The carbon dioxide produced during the process of respiration is totally used up the photosynthesis so no extra carbon dioxide is needed. ​

2)The photosynthesis process is slowing down so the uptake of carbon dioxide is releasing and the net movement of carbon dioxide is zero at that particular time.​

​

Any of these two correct? can i get full mark if this question worth 3marks?! ​

and this too? this is quite important i think...

 

[luckywang]

what are the functions of nitrifying,denitrifying,nitrogen fixing and decay bacteria?

nitrifying= convert ammonium compound to nitrite then to nitrate
denitrifying= convert nitrate to atmosphere nitrogen
decay bacteria= decompose dead organism and produced/release ammonium compound?

is release or produce? i forgot....

 

[sedanx]

what are the functions of nitrifying,denitrifying,nitrogen fixing and decay bacteria?

nitrogen fixing bac convert nitrogen to ammonia and ammonium compounds
nitrifying bac convert ammonium compounds to nitrites and then to nitrates which plants absorb
decomposers break down proteins from dead animals, plants, etc and change to amino acids and then to ammonia ... ao the cycle continues
denitrifying bac change nitrates to nitrogen ... so nitrates are lost from the soil

 

[Maz]

nitrifying= convert ammonium compound to nitrite then to nitrate
denitrifying= convert nitrate to atmosphere nitrogen
decay bacteria= decompose dead organism and produced/release ammonium compound?

is release or produce? i forgot....

It seems you forgot nitrogen fixing bacteria whose role is to convert atmospheric nitrogen into ammonia.

 

[malay]

help me on this?

about dat,i also want to know?! iv heard its no more in our syllabus buh iv seen alot of questions in the pastpapers.

 

[sedanx]

help me on this?

platelets gather in the cut region
secrete thrombin
which converts soluble fibrogen to insoluble fibrin
which forms a mesh over the wound
which traps RBCs and more platelets
which forms a scab over the wound

 

[kitecrystal]

nitrifying= convert ammonium compound to nitrite then to nitrate
denitrifying= convert nitrate to atmosphere nitrogen
decay bacteria= decompose dead organism and produced/release ammonium compound?

is release or produce? i forgot....

thank you

 

[luckywang]

It seems you forgot nitrogen fixing bacteria whose role is to convert atmospheric nitrogen into ammonia.

oh... sorry my fault....

 

[luckywang]

http://www.xtremepapers.com/papers/...nal O Level/Biology (5090)/5090_s11_qp_12.pdf
question 11
1=phloem
2=cambium
3=xylem?
then why answer is C? i cannot find answer >.< coz my answer is water=3 sucrose=1

 

[Maz]

about dat,i also want to know?! iv heard its no more in our syllabus buh iv seen alot of questions in the pastpapers.

For extended syllabus? yes, we have to know the basics of blood clotting.

Describe the process of clotting (fibrinogen to
fibrin only)

This is mentioned in the syllabus copy of 2012.

 

[kitecrystal]

nitrogen fixing bac convert nitrogen to ammonia and ammonium compounds
nitrifying bac convert ammonium compounds to nitrites and then to nitrates which plants absorb
decomposers break down proteins from dead animals, plants, etc and change to amino acids and then to ammonia ... ao the cycle continues
denitrifying bac change nitrates to nitrogen ... so nitrates are lost from the soil

thanks a lot

 

[sedanx]

and this too? this is quite important i think...

first mention: wen the light is dim (low intesity - eg. dawn or dusk)
rate of respiration = rate of photosynthesis
so CO2 released = CO2 used
is called compensation point

 

[Maz]

Please someone, What is ATP?

 

[luckywang]

For extended syllabus? yes, we have to know the basics of blood clotting.

This is mentioned in the syllabus copy of 2012.

... why i cant find it? i print wrong syllabus??!!!!? OMG!

 

[luckywang]

first mention: wen the light is dim (low intesity - eg. dawn or dusk)
rate of respiration = rate of photosynthesis
so CO2 released = CO2 used
is called compensation point

thanks!!!!!!!!!!!!!!!!

 

[malay]

and this too? this is quite important i think...

compensation point is the point (usually dawn and dusk) when there is no net movement of CO2.This happens cuz the rate of respiration and photosynthesis r at equilibrium i.e amount of CO2 absorbed for photosynthesis is equal to the amount of CO2 released by respiration.....n also stop crying!