Biology; Chemistry; Physics: Post your doubts here!

[ayeshaK]

whats insertion? :S

The opposite end of the muscle is called the insertion but its not in our syllabus !! It doesnt come !!

 

[Rimsa]

Xylem will give negative in both iodine and benedict !! But i guess phloem will give negative in iodine but benedicts would be positive because phloem has sugars !! ?

doesnt it carry sucrose? :s

 

[Rimsa]

Yes and sucrose is a reducing sugar giving +ve result wid benedict ! ?

its a disaccharide :s here. this is from wikipedia

Sucrose is thus a non-reducing sugar which does not react with Benedict's reagent. Sucrose indirectly produces a positive result with Benedict's reagent if heated with dilute hydrochloric acid prior to the test, although after this treatment it is no longer sucrose.

 

[ayeshaK]

doesnt it carry sucrose? :s

Yes It carries sucrose so sucrose is a non reducing agent so the result would be -ve ..i mistook the ques

 

[screamingskull]

doesnt it carry sucrose? :s

Xylem carries WATER and MINERAL SALTS while phloesm transports sugar from the leaves to other parts of the plant.

 

[ayeshaK]

Xylem carries WATER and MINERAL SALTS while phloesm transports sugar from the leaves to other parts of the plant.

Yes but it wuld give -ve with reducing sugar !!

 

[Rimsa]

Yes It carries sucrose so sucrose is a non reducing agent so the result would be -ve ..i mistook the ques

Xylem carries WATER and MINERAL SALTS while phloesm transports sugar from the leaves to other parts of the plant.

so why is this all -ve option not here? its winter 2011, paper12

 

[screamingskull]

so why is this all -ve option not here? its winter 2011, paper12 View attachment 8879

The answer here is D because Xylem neither carries starch nor iodine but phloem carries the reducing sugars but NOT starch that is why iodine test produces negative result in both tissues.

 

[ayeshaK]

[

so why is this all -ve option not here? its winter 2011, paper12 View attachment 8879

The answer here is D because they are asking u about the phloem !! Reduscind sugar is present as the cell sap that is translocated by the sive tubes contains sugars so option will be D !! They are not asking directly from roots so in translocation sugarsare also present !!

 

[Rimsa]

The answer here is D because Xylem neither carries starch nor iodine but phloem carries the reducing sugars but NOT starch that is why iodine test produces negative result in both tissues.

then where is that option in here? w08 =x

[
The answer here is D because they are asking u about the phloem !! Reduscind sugar is present as the cell sap that is translocated by the sive tubes contains sugars so option will be D !! They are not asking directly from roots so in translocation sugarsare also present !!

 

[screamingskull]

then where is that option in here? w08 =xView attachment 8881

In this the answer is also D since Phloem contains sucrose the non-reducing sugar
Just keep in mind that the phloem contains sucrose but if hydrolysed and then neutralised it may contain reducing sugar (this will not be specified in paper 1 obviously either one of the two options will be given and both are correct-other options are completely illogical)

 

[ayeshaK]

then where is that option in here? w08 =xView attachment 8881

d would be the option !! Because in phloem sugars are also present but in this case we wouls take sucrose here !! So all option are not correct except the D

 

[Rimsa]

In this the answer is also D since Phloem contains sucrose the non-reducing sugar
Just keep in mind that the phloem contains sucrose but if hydrolysed and then neutralised it may contain reducing sugar (this will not be specified in paper 1 obviously either one of the two options will be given and both are correct-other options are completely illogical)

alright. thanku

 

[bogus]

i did find it for physics,maths and chemistry .but not for bio ...
check out here
http://www.cambridgestudents.org.uk/subjectpages/biology/folder.2005-03-15.1931915574/

Oh sorry ...I dont take bio so .... I took the phy and chem wali from there so i assumed bio would be there to

 

[Spidey21]

then where is that option in here? w08 =xView attachment 8881

after reading your both the posts i was like (whats going on with examiner) but you should look the options under X ( xyelm) which is supposed to be giving -ve in both....so there is no other possibility but D if you look at the options under Xylem...

 

[Rimsa]

after reading your both the posts i was like (whats going on with examiner) but you should look the options under X ( xyelm) which is supposed to be giving -ve in both....so there is no other possibility but D if you look at the options under Xylem...

hmm right. when i saw this, i made my mom look at them cuz i thought it was imagining =P

 

[Spidey21]

hmm right. when i saw this, i made my mom look at them cuz i thought it was imagining =P

LOL true..

 

[khizer shahab]

The table gives data about four substances.
Which substance has particles in a disorderly arrangement at room temperature?

melting point/ oC l boiling point/oC
A –114.................. l ... –80
B 120 ....................l .....445
C 750 ....................l..... 1407
D 1610.................. l..... 2230

cant understand the query

 

[khizer shahab]

Which gas has the slowest rate of diffusion?
A ammonia, NH3
B methane, CH4
C oxygen, O2
D nitrogen, N2

this one too

 

[Rimsa]

The table gives data about four substances.
Which substance has particles in a disorderly arrangement at room temperature?

melting point/ oC l boiling point/oC
A –114.................. l ... –80
B 120 ....................l .....445
C 750 ....................l..... 1407
D 1610.................. l..... 2230

cant understand the query

option A cuz gases have melting and boiling point below room temperature

Which gas has the slowest rate of diffusion?
A ammonia, NH3
B methane, CH4
C oxygen, O2
D nitrogen, N2

this one too

calculate their molecular mass. the heaviest will have lowest rate of diffusion.