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AS BIOLOGY P-33

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Can some one please share the food test procedures and will we have a graticule scale and all that?
i rely hope this is not too messy
biuret test : add an equal amount of NaOH to a solution of the food, mix carefully.
add a few drops of 1% CuSO4, do not shake the mixture.
a PURPLE/MAUVE COLOR is a positive result: protein is present.

iodine test:
1. If the food to be tested is liquid, go to 2. If the food to be tested is solid, make an extract. Grind crush or chop a
small amount and put into a test tube to a depth of about 2cm. Add a similar amount of distilled water and stir with
a glass rod. Allow to stand for a few minutes.
2. Draw up some of the clear liquid into a pipette and then either transfer it into another test tube or put drops onto
a white tile.
3. Add on drop of (brown) iodine solution on the tile and look for a color change. A blue-black color indicates
the presence of starch.

benedicts' test :for reducing sugar

. Addabout 5cm3of the reagent to a small amount of sample in a testtube.
.Stand the test tube in boiling water for a few minutes.

A colour change through green to yellow, brown and finally to red indicates the presenceof reducingsugar

for non reducing sugar :
01.If the sample isn't already in liquid form grind it up in water.
2. Add 2cm3(cubed) of the food sample to a test tube with 2cm of benedict's reagent
3. gently) boil in a water bath for 5 mins
4. If a NON-REDUCING sugar is present then the solution will remains BLUE
5. In this case another 2cm3 of the food sample to 2cm3 of (dilute) hydrochloric acid in a test tube(as the hydrochloric acid hydrolyzes the disaccharide into its monomer constituents .i.e. sucrose --> glucose + fructose)
6. (Slowly) add sodium hydrogencarbonate to the test tube(to neutralise the hydrochloric acid as Benedict's reagent can't work in acidic conditions)
7. Now re-test the solution by heating it with the 2cm3 of Benedict's reagent for 5 mins, this time the solution should turn from blue to orange-brown/brick red because reducing sugars are present(.i.e. glucose and fructose)due to the hydrolysis of the disaccharide (sucrose)
 
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Guys the test for non- reducing sugar is, first taking the non-red sugar with benedicts and heating it in water bath for a specified time and then adding HCL and then neautralising it with sodium bicarbonate.. ? am I right
you add the acid + neutralise it BEFORE carrying Benedict's test
 
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Hello. Can you guys help me distinguish between LPP and HPP diagram? I couldnt get the part where they say do not draw individual cell in LPP.
what is full form of lpp and hpp
 
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Guys all we need now are the plan diagrams of Dicot stem and root.Someone please post them here.It would be much appreciated. :)
 
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green -- means traces present . yellow --- low amounts ... orange --- moderate amounts ....brick red --- high amounts
yes i know this i mean when they ask us record the time for the first colour change.. so when it turns green ill record the time?
 
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Somebody posted this in some other thread a few months ago..dont know who.. this might help clear many confusions regarding food tests and microscopy :)
 

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test upon sucrose, glucose, starch and fungal amylase.
How do we test the sucrose ,glucose,starch and fungal amylase
 
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guys in cell division if a cell is in prophase should we draw the chromatin threads in our low power diagram and nuclelous if we see them
 
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If you are reffering to these then i must tell you these are not the "planned diagrams" .These are original images of specimens.
 

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  • image004.jpg
    image004.jpg
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  • MonocotStem.gif
    MonocotStem.gif
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