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Methods:
Part 1: Carbohydrates
Investigation 1: Monosaccharides and Disaccharides
1. Before the experiment, potato suspension as prepared by crushing using the mortar.
!. "ix test tubes ere prepared.#. In a test tube, 1m$ of a 1% g$ucose so$ution as added.
&. "tep ! as repeated by adding 1m$ of ater, 'uice, soft drin(, potato suspension and
soy mi$( to each of the other five test tubes.). )m$ of Benedict*s so$ution as added to each six tubes.
+. hese six tubes ere incubated in the ater bath for #minutes.
-. he co$our changes of the so$ution ere observed and hether a precipitate has
formed as noted.
. he resu$ts ere recorded in a tab$e.
Investigation !: "tarch
1. ! m$ of starch so$ution, ater, 'uice, soft drin(, potato suspension and soy mi$( ere
added to + test tubes respective$y.
!. o each tube, ) drops of iodine reagent ere added and mixed e$$.#. he observations ere recorded.
Investigation #: /ydro$ysis of Carbohydrates
a) Hydrolysis1. + m$ of sucrose so$ution and ater ere added to test tube 1 and ! respective$y.
!. +m$ of the samp$es that shoed the negative resu$t in Investigation 1 ere added to
test # and &.#. # m$ of hydroch$oric acid as added to each tube and mixed e$$.
&. hese tubes ere put in the boi$ing ater for ) minutes.
b) Benedict’s test ). 0fter ) minutes of incubation, $ m$ of each samp$e ere transferred to ne test tubes
respective$y and added ith &m$ of Benedict*s so$ution.+. he observations ere recorded.-. he remaining test tubes ere continuing incubated for 1 minutes.
. 0fter 1 minutes, step ) as repeated by transferring the so$utions
2. he observations ere recorded.1. ) drops of iodine reagent ere added to test tubes in step .
11. he observations ere recorded.
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Part !: Proteins
1. ! test tubes ere prepared.
!. # m$ of 1% egg a$bumin and disti$$ed ater ere added to each test tube respective$y.
#. # m$ of concentrated potassium hydroxide ere added to both test tubes and mixed
e$$.
&. 1 m$ of .)% copper su$phate ere added to these to tubes.
). he observations ere recorded.
Part #: 3ipids
1. + sma$$ s4uares of bron papers ere prepared.
!. he papers ere $abe$$ed.
#. 0 tiny drop of vegetab$e oi$, disti$$ed ater, 'uice, soft drin(, potato suspension and
mi$( ere put onto the papers.
&. he drops ere rubbed gent$y ith different fingertips.). he spots ere a$$oed to dry.+. he observations ere recorded.
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5esu$t:
Part 16Investigation 17
Before incubation
0fter incubation
8uice
Mi$( Potato
suspension
"oft
drin(
Positive
contro$
9egative
contro$
8uice
Mi$(
Potato sus pension
"oft drin(
Positive contro$
9egative
contro$
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Investigation !
Investigation #
0fter ) minutes incubation
0fter ) minutes incubation 6tested ith Benedict*s test7
Positive
contro$
Mi$(
8uice
"oft drin(
Potato
suspension
9egative
contro$
Potato suspensionMi$(
Positive
contro$ 9egative
contro$
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0fter 1 minutes incubation 6test ith iodine reagent7
Potato suspensionMi$(
"oy mi$( Potato
sus ensionPotato suspension
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Part !
Disti$$ed ater
0$bumin so$ution
"oft drin( 8uice
Potato suspension
Mi$(
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Part #
Disti$$ed ater
8uice"oft drin(
egetab$e oi$
Potato suspension
"oy Mi$(
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ab$e 1: Investigation 1
"amp$es Before incubation 0fter incubation Positive;9egative
5esu$t
Positive contro$ e$$o co$our
so$ution formed
C$oudy b$ue so$ution
formed
9egative
Potato suspension C$oudy vio$et co$our
formed
C$oudy b$ue so$ution
formed
9egative
ab$e !: Investigation !
"amp$es Co$our 0fter incubation Positive;9egative 5esu$t
Positive contro$ >e$$o co$our so$ution formed =
9egative contro$ >e$$o co$our so$ution formed =
8uice he co$our remain unchanged 9egative
"oft drin( he co$our remain unchanged 9egative
"oy mi$( he co$our remain unchanged 9egative
Potato suspension Dar( b$ue so$ution formed Positive
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ab$e #: Investigation #
"amp$es Benedict*s test Iodine test
minutes
)minutes 1minutes
minutes
)minutes 1minutes
"oy Mi$( 9egativ
e
9egative 9egative = = =
Potato
suspension
9egativ
e
9egative 9egative 9egativ
e
Positive 9egative
ab$e &: Part !
"amp$es Co$our changes Biuret*s test
?gg 0$bumin 0 vio$et co$our so$ution formed =
Disti$$ed ater 0 b$ue co$our so$ution formed. =
Mi$( 0 $ight purp$e so$ution formed Positive
"oft drin( 0 bron co$our so$ution formed 9egative
8uice 0 $ight orange so$ution formed 9egative
Potato 0 dar( vio$et co$our so$ution
formed
Positive
ab$e ): Part #
"amp$es