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biochem prac report 1 Paper

Words: 1269, Paragraphs: 76, Pages: 5

Paper type: Report , Subject: Biology

4000302260center9/30/2019

33000950009/30/2019

420003175000880009408795450000420003175000175001870710BIOCHEMISTRY REPORT PRACTICLE 4:ELZE WILKE 2018269395

MONDAY 14:00

DEMI’S: NALEDI & LIVE

450000BIOCHEMISTRY REPORT PRACTICLE 4:ELZE WILKE 2018269395

MONDAY 14:00

DEMI’S: NALEDI & LIVE

Contents

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TOC o “1-3” h z u Experiment 1: Molisch’s test PAGEREF _Toc20731484 h 2Aim PAGEREF _Toc20731485 h 2Introduction PAGEREF _Toc20731486 h 2Results PAGEREF _Toc20731487 h 2Conclusion PAGEREF _Toc20731488 h 3References PAGEREF _Toc20731489 h 3Experiment 2: Benedict’s test for reducing sugars PAGEREF _Toc20731490 h 4Aim PAGEREF _Toc20731491 h 4Introduction PAGEREF _Toc20731492 h 4Results PAGEREF _Toc20731493 h 4Conclusion PAGEREF _Toc20731494 h 5References PAGEREF _Toc20731495 h 5Experiment 3: Polysaccharide test PAGEREF _Toc20731496 h 6Aim PAGEREF _Toc20731497 h 6

Experiment 1: Molisch’s testAimThe Molisch’s test is to identify carbohydrates qualitatively in other biomolecules.

IntroductionAs carbohydrates are the main energy source of all food, we still need to use the wright diet.This test is based on the dehydration of carbohydrates by using sulfuric acid to produce furfural and its derivative. When the monosaccharide, wich is the smallest sugar ther is, are mixed and treated with concentrated sulfuric acid, sugars are removed in the form of water, furfural and hydroxymethyl furfural. These products react with ?-naphthol to give a purple coloured complex.

Results

Test solution Result Observation Reason

Fructose Positive (Fast) Purple It is a sugar. Monosaccharide

Sucrose Positive (Slow) Purple It is a sugar. Disaccharide

Starch Positive (Slow) Purple It is a more complex sugar. Polysaccharide

Player A Negative Yellow It is not a sugar. Not a carbohydrate.

Player B Positive (Fast) Purple It is a sugar. Monosaccharide

b) When the acid is added, at first there is nothing, then it turns into a purple complex.

c) The sulfuric acid a strong dehydration reagent that dehydrates the sugars in the Molisch test into furfural and its derivatives

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Conclusion

Monosaccharide give a fast positive response (Fructose), polysaccharide and disaccharide (Sucrose and Starch) gives a slow positive response. Fructose, sucrose, starch and player B are all carbohydrates and tested positive in the molisch test. Player A tested negative in the molisch test, this will indicate that it is not a carbohydrate. The molisch test confirms that all carbohydrates form furfural when reacted with sulfuric acid.

References BIBLIOGRAPHY admin, n.d. All medical tests( molisch test). [Online] Available at: allmedtest.com[Accessed 2 October 2016].

Karki, G., 2018. Online Biology notes (test for carbohydrates). [Online] Available at: onlinebiologynotes.com

sciences, U. f. o. n. a. a., 2019. biochemistry and microbology practicle manual. In: s.l.:s.n., pp. 28-32.

youtube, n.d. molisch test-qualitative test carbohydrates. [Online] [Accessed 25 october 2012].

Experiment 2: Benedict’s test for reducing sugarsAim

This test identifies reducing sugars in other biomolecules that are qualitatively determined.

IntroductionWhen the reagent of benedict is mixed with the carbohydrates and heated the colour of the mixture will change if there is reducing sugars. Reducing sugars consist of free aldehydes, this means that copper (II) will transform into copper (I).

When the precipitate is heated it will change color into red (concentrated sugar), orange (diluted sugar) and if it doesn’t it will stay blue.

Results

Test solution Result Observation Reason

Fructose Positive Red

This means it is a concentrated sugar. Reducing sugars are able to reduce copper2 to copper1

Sucrose Negative Blue No reducing sugars.

Starch Negative Blue No reducing sugars.

Player A Negative Blue No reducing sugars.

Player B Negative Blue No reducing sugars.

b) The principle of this test is that Benedict’s reagent solution and reducing sugars are heated in the presence of an alkali they get converted to powerful reducing species known as enediols.CITATION Wor17 l 7177 (Chemicals, 2017)Testing for reducing sugars, if the color of the reaction changes there is a presence of simple carbohydrates.

72789269759300c) The statement that only monosaccharides are reducing, it is true. For fructose is a monosaccharide and it is the only carbohydrate that change color from blue to red. The other structures did not change color.

Conclusion

This benedict test is qualitative for it the fructose changed color from blue to brick red. The other samples did not change there were no reducing sugars involved in these solutions. Only fructose has reducing sugars, it means that it is also monosaccharide. Only they have reducing sugars. The C=O bonds in fructose is broken during dehydration, where other samples are formed. Disaccherides will not have a reaction on the Benedict’s test.

References BIBLIOGRAPHY Chemicals, W. o., 2017. benedicts reagent for monosaccharides. [Online] [Accessed 4 Febuary 2017].

info, m., 2019. benedicts test. [Online] Available at: microbiolgyinfo.com

Karki, G., 2018. Online Biology notes (test for carbohydrates). [Online] Available at: onlinebiologynotes.com

report, C. l., 2016. benedicts test, s.l.: s.n.

sciences, U. f. o. n. a. a., 2019. biochemistry and microbology practicle manual. In: s.l.:s.n., pp. 28-32.

Experiment 3: Polysaccharide testAim

To test the presence of polysaccharide in biomolecules by using the Iodine test.

Introduction

Iodine is added to the test solution to test the presence of starch if the test is positive then the solution will turn blue-black, if there is no starch or polysaccharide present then the solution will stay yellow or orange. The iodine must be dissolved in water to make a tri-iodine complex. This test was applied to all test samples.

Results

Test sample Result Observation Reason

Fructose Negative Orange No polysaccharide present.

Sucrose Negative Orange No polysaccharide present.

Starch Positive Black There is polysaccharide present.

Player A Negative Orange No polysaccharide present.

Player B Negative Orange No polysaccharide present.

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Conclusion

There will be a positive test result if there is starch present, the colour of the solution will change. The amylose, or straight chain portion of starch, forms helices where iodine molecules assemble, forming a dark blue colour CITATION rep16 l 7177 (report, 2016). There will only be a positive polysaccharide test if starch is present in the test solution. The iodine molecule slips inside of the amylose coil. Amylose is responsible for the blue-black colour change.

References

BIBLIOGRAPHY Chemicals, W. o., 2017. benedicts reagent for monosaccharides. [Online] [Accessed 4 Febuary 2017].

libretext, n.d. starch and iodine. [Online] [Accessed 5 june 2019].

report, C. l., 2016. iodine test, s.l.: s.n.

sciences, U. f. o. n. a. a., 2019. biochemistry and microbology practicle manual. In: s.l.:s.n., pp. 28-38.

Experiment 4: Amino acids & Proteins

Aim

Testing for the presence of amino acids in a protein or other biomolecules and characterize their properties.

Introduction

Protein hydrolysis takes place when there is destruction of the protein’s amino acid. Denaturation is when there is destruction of the 3D-stucture of a protein. The 3D- structure is dependent on hydrogen bonds, interionic bonds (salt bridges) and disulphide bond. A protein will denaturate if there is any interference.

Protein identification

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Test sample Result Explanation

1 Positive, violet Presence of protein

2 Negative, blue No presence of protein

3 Negative, blue No presence of protein

4 Positive, violet Presence of protein

Denaturing protein

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Test sample Result Explanation

1 heat the upper part of test tube White Denaturation taking place

2 2ml alcohol 70% White Denaturation taking place

3 1ml tannic Light brown Denaturation taking place

4 1.5 ml mercuric chloride No color change No denaturation taking place

5 shake test tube No color change No denaturation taking place

Picric acid is an antistringent and an antiseptic, it causes contraction of skin cells. Replaced by silver nitrate.

It is an antiseptic and disinfectant, it kills unwanted microbes.

The egg white contains proteins that have sulfhydryl (-SH) groups. They can bind to heavy metal ions. The emetic must be given, for fumes to escape.

Conclusion

There will only be a positive test biuret test if there is proteins present in the test sample. There will only be denaturation if heat, alcohol and picric is added to the solution. The positive test will indicate a white or of light brown solution at the end of the experiment. The protein will not denaturate if it is shaken and if mercuric chloride is added to it. The test sample will stay the same color.

References

BIBLIOGRAPHY Chemicals, W. o., 2017. amino acids and proteins. [Online] [Accessed 4 Febuary 2017].

libretext, n.d. biuet test and amino acids. [Online] [Accessed 5 june 2019].

report, C. l., 2016. biuret test, s.l.: s.n.

sciences, U. f. o. n. a. a., 2019. biochemistry and microbology practicle manual. In: s.l.:s.n., pp. 28-38.

About the author

This sample is completed by Emma with Health Care as a major. She is a student at Emory University, Atlanta. All the content of this paper is her own research and point of view on biochem prac report 1 and can be used only as an alternative perspective.

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