AS BIOLOGY P-33

[falcon678]

But I heard it would be the enzyme practical? :S

well this time it is a food test...

 

[Alool]

and what about serial dilution? my teacher said that it's coming

 

[falcon678]

and what about serial dilution? my teacher said that it's coming

well i dun think thtz coming either......

 

[beeloooo]

GUYS , HE MEANT THAT
for sucrose do the non reducing test
for glucose do the reducing test
for starch do the iodine test
and for fungal amylase do the biuret test for proteins

don't confuse urselves... and if theres anything extra it will be clear when u read the question and instructions

falcon678 is she right na ?

 

[falcon678]

falcon678 is she right na ?

yeah she is.....

 

[stareaj]

In microscope if its five marks how many similaritys and differences shuld we give?
We only give.similarities in compare and contrast?

 

[falcon678]

In microscope if its five marks how many similaritys and differences shuld we give?
We only give.similarities in compare and contrast?

u ve to compare n contrast...meaning finding bout similarites n differences.....

 

[Raghad Dia]

Guys what is the difference between Reducing sugars & non reducing??

 

[aleezay]

hey friends need a gud website for microscopic images

Google them Use the syllabus to find out what you should be able to identify and google it..

 

[Rozy]

Guys what is the difference between Reducing sugars & non reducing??

very simple actually, it might be confusing because both have similar procedure. Benedict's Test is carried out for both the sugar
for NON-REDUCING SUGARS (- sugars which do not have an aldehyde functional group)
1.Add 2 cm3 of the sample solution to a test tube.
2.Add 1 cm3 of dilute hydrochloric acid and boil for one minute.
3.Allow the tube to cool and then neutralize the acid with sodium hydrogen
carbonate. take caution as there may be effervescence.
[check the pH of the solution]
Now,
Then carry out Benedict's Test as for REDUCING SUGARS:
4.Add an 2 cm3 of Benedict's solution to the test tube and swirl or vortex the
mixture.
5.Leave the test tube in a boiling water bath for about 5 minutes, or until the colour
of the mixture does not change.
6.Observe the colour changes during that time as well as the final colour.
INTERPRETATION OF THE OBSERVATION {v.imp}
No colour change (mixture remains blue) = No non-reducing sugar present
Green = Trace amounts of non-reducing sugar/reducing sugar present
Yellow = Low amounts of non-reducing sugar/reducing sugar present
Orange = Moderate amounts of non-reducing sugar/reducing sugar present
Brick Red = Large amounts of non-reducing sugar/reducing sugar present

 

[Ahmad Zaeem]

Ok guys here's what i found ...i hope it concides with your info ...if it does then it is confirmed

1 syringe 10ml
2 syringe 5 ml
3 dropers
1 glass rod
1 plastic beaker 250 ml for washing
1 plastic beaker 250 ml for waste
paper towel
3 Beaker 50 ml
6 boiling tubes with bungs
1 white tile
testube rack
1 test tube holder
1 spatulal
Iodine solution
Benedicts solution
Hydrochloric acid
Biurets reagent
weighing bottle sodium hydrogen carbonate
1 Microscope ...



Tadaa!!!!...Enjoy...

 

[Raghad Dia]

very simple actually, it might be confusing because both have similar procedure. Benedict's Test is carried out for both the sugar
for NON-REDUCING SUGARS (- sugars which do not have an aldehyde functional group)
1.Add 2 cm3 of the sample solution to a test tube.
2.Add 1 cm3 of dilute hydrochloric acid and boil for one minute.
3.Allow the tube to cool and then neutralize the acid with sodium hydrogen
carbonate. take caution as there may be effervescence.
[check the pH of the solution]
Now,
Then carry out Benedict's Test as for REDUCING SUGARS:
4.Add an 2 cm3 of Benedict's solution to the test tube and swirl or vortex the
mixture.
5.Leave the test tube in a boiling water bath for about 5 minutes, or until the colour
of the mixture does not change.
6.Observe the colour changes during that time as well as the final colour.
INTERPRETATION OF THE OBSERVATION {v.imp}
No colour change (mixture remains blue) = No non-reducing sugar present
Green = Trace amounts of non-reducing sugar/reducing sugar present
Yellow = Low amounts of non-reducing sugar/reducing sugar present
Orange = Moderate amounts of non-reducing sugar/reducing sugar present
Brick Red = Large amounts of non-reducing sugar/reducing sugar present

So disaccharides are non reducing sugars while monosaccharides are reducing sugars??

 

[NidaChaudhary]

guys same as last time...a day befre exam....late nite!

when??

 

[aleezay]

Thought I should share this:

Candidates should give calculated quantities to the same number of significant figures as the measured
quantity that has the smallest number of significant figures. For example, if a candidate collects values of
time measured to 1 significant figure and values of gas volume measured 2 significant figures, then the
calculated rate should be given to 1 significant figure, but not 2 or more.

Since 2sf would've been allowed for physics in such a case. Didnt know they were not allowed for biology.

 

[aleezay]

So disaccharides are non reducing sugars while monosaccharides are reducing sugars??

All monosaccharides and disaccharides (atleast the ones in our syllabus) are reducing except for sucrose.

 

[falcon678]

when??

uumm surf the prev pages... u will find the questions...

 

[comrade]

So disaccharides are non reducing sugars while monosaccharides are reducing sugars??

Monosaccharides are reducing sugars. As for disaccharides, they are non-reducing sugars like you said.

 

[Ahmad Zaeem]

shahzada cha gaya level boy keep it up111!!!!!!!

G shukriya janaab !!!!...

 

[Ahmad Zaeem]

Monosaccharides are reducing sugars. As for disaccharides, they are non-reducing sugars like you said.

Boy all dissacharides are reducing sugers except Sucrose .........!!!!this is what i read in the O level book

 

[aleezay]

Monosaccharides are reducing sugars. As for disaccharides, they are non-reducing sugars like you said.

disaccharides are NOT non-reducing. Except for sucrose.