phloem transports sugar and amino acids

8/8/2019 Phloem Transports Sugar and Amino Acids

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Phloem transports Phloem transportssugar and amino acids.sugar and amino acids.How do you knowHow do you know

that?that? CrystalCrystalSaeamSaeam

Wei XuanWei XuanChang HuiChang Hui

Alisia Alisia


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So what are we testing for?So what are we testing for?

The presence of aminoThe presence of amino

acids in the phloem,acids in the phloem,through the use of acylthrough the use of acyl

chloride and biuretchloride and biuretsolution.solution.


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Apparatus and materials Apparatus and materialsMaterialsMaterials30 ml of Diluted30 ml of Dilutedblack inkblack ink60 ml of Benedict s60 ml of Benedict ssolution (Copper (II)solution (Copper (II)Sulphate)Sulphate)20ml of distilled20ml of distilledwaterwater20ml of acyl chloride20ml of acyl chloride(eg. CH3COCL)(eg. CH3COCL)10ml of sodium10ml of sodiumhydroxidehydroxide

Apparatus Apparatus5 beakers5 beakers3 portions of the3 portions of thestalk of celerystalk of celeryTripod standTripod standBursen burnerBursen burner

LighterLighter


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proceduresproceduresStep 1Step 1 : Remove 3 portions of the stalk of celery: Remove 3 portions of the stalk of celeryand place them in a beaker of 30ml of dilutedand place them in a beaker of 30ml of dilutedblack ink. This is to differentiate between theblack ink. This is to differentiate between thexylem tube and the phloem tube .xylem tube and the phloem tube .

Step 2:Step 2: Cut a portion of the stalk of celery intoCut a portion of the stalk of celery intotwo to show the phloem and xylem tubes. Thetwo to show the phloem and xylem tubes. Thetube that remains colourless is the phloem tube.tube that remains colourless is the phloem tube.

Step 3:Step 3: Place them in a beaker of 20ml ofPlace them in a beaker of 20ml ofBenedict s solution containing copper(II)Benedict s solution containing copper(II)

sulphate and shake the mixture. This is to test forsulphate and shake the mixture. This is to test forthe presence of sugars in the phloem tube.the presence of sugars in the phloem tube.

Step 4Step 4 : Leave the test tube in a beaker of boiling: Leave the test tube in a beaker of boilingwater for 5 minutes.water for 5 minutes.


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Step 5:Step 5: As a control experiment, repeat As a control experiment, repeat

step 2, 3 and 4 using 20ml of distilledstep 2, 3 and 4 using 20ml of distilledwater and 20ml of Benedict s solution.water and 20ml of Benedict s solution.Step 6:Step 6: Observe the results.Observe the results.Step 7:Step 7: Cut another portion of the stalk ofCut another portion of the stalk ofcelery into two to show the phloem andcelery into two to show the phloem andxylem tubes. The tube that remainsxylem tubes. The tube that remainscolourless is the phloem tube.colourless is the phloem tube.Step 8:Step 8: Place them in a beaker of 20ml ofPlace them in a beaker of 20ml ofacyl chloride (eg. CH3COCL). This is theacyl chloride (eg. CH3COCL). This is theallow polypeptides to be formed throughallow polypeptides to be formed throughcondensation reaction.condensation reaction.


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Step 9Step 9 : Place the solution and the: Place the solution and the

celery into another beaker of 10ml ofcelery into another beaker of 10ml ofsodium hydroxide solution for Biuretsodium hydroxide solution for BiuretTest.Test.Step 10:Step 10: Add 1% of copper (II) Add 1% of copper (II)sulphate solution, drop by drop,sulphate solution, drop by drop,shaking after every drop, till aboutshaking after every drop, till about20ml of copper (II) sulphate is20ml of copper (II) sulphate ispoured inside the solution.poured inside the solution.Step 11Step 11 : Shake well and allow the: Shake well and allow themixture to stand for 5 minutes.mixture to stand for 5 minutes.Observe the changes.Observe the changes.


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E xpected ResultsE xpected Results

Biuret test:Biuret test: the solution turns fromthe solution turns fromblue to pink. Amino acids in theblue to pink. Amino acids in the

phloem tube of the celery is convertedphloem tube of the celery is convertedto polypeptides through condensationto polypeptides through condensationreaction which can be tested for Biuretreaction which can be tested for Biurettest which will turn the blue solution,test which will turn the blue solution,containing sodium hydroxide andcontaining sodium hydroxide andcopper(II) sulfate into pink to indicatecopper(II) sulfate into pink to indicatethe presence of polypeptides.the presence of polypeptides.


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Benedict s solution test:Benedict s solution test: The solutionThe solutionchanges its colour from blue to brickchanges its colour from blue to brick- -

red. Glucose in the phloem tube of thered. Glucose in the phloem tube of thecelery can reduce the copper (II) incelery can reduce the copper (II) inBenedict s solution to copper (I). TheyBenedict s solution to copper (I). Theyproduce a brickproduce a brick- -red precipitate ofred precipitate of

copper (I) oxide when boiled withcopper (I) oxide when boiled withBenedict s solution.Benedict s solution.

E xpected ResultsE xpected Results


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THE EN DTHE EN D

phloem transports sugar and amino acids

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