Bio Lab 5biological Importnt Chemi Compound 3lx3g

NAME: MOHD SAFWAN BIN MOHD SHAFIE CLASS:M04N PRACTICAL 5 Title Objective

: Identification of some biological important chemical compound : a) To identify some biological important chemical compound b) To know the specific reagent for certain chemical constituent Apparatus : Refer to Biology handbook page 112 Materials : Refer to Biology handbook page 112 Procedure : Refer to Biology handbook from page 113 to page 115 Data collection: PART 1 A.STARCH Reagent Dilute iodine

Substances  Starch suspension  Potato Tuber

Observation  The solution’s colour changes from yellow to blue-black.  Potato tuber were coloured to blue-black  Under microscope observation, all cells were coloured into blue-black

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Details When starch is mixed with iodine in water, an intensely colored starch/iodine complex is formed. But it seems that the iodine gets stuck in the soluble starch. The starch forces the iodine atoms into a linear arrangement in the central groove of the soluble starch coil, giving the complex its intense blue color.

B.GLUCOSE Reagent Benedict’s reagent

Subtances Glucose solution

Observation  The solution’s colour changes from clear blue to cloudy green to yellow and finally to a red precipitate when boiled.

Details Aqueous glucose is mixed with Benedict's reagent, a solution of copper sulfate, sodium hydroxide, and tartaric acid. The mixture is heated. Carbohydrates which react with Benedict's reagent to reduce the blue copper (II) ion to form a brick red precipitate of copper (I) oxide are classified as reducing sugars.

C. FRUCTOSE Reagent Benedict’s reagent

Subtances Apple

Observation  Cell change colour from blue-black to brown  The microscope observation is attached at the back.

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Details Aqueous fructose is mixed with Benedict's reagent, a solution of copper sulfate, sodium hydroxide, and tartaric acid. The mixture is heated. Carbohydrates which react with Benedict's reagent to reduce the blue copper (II) ion to form a brick red precipitate of copper (I) oxide are classified as reducing sugars.

D. SUCROSE Reagent Benedict’s reagent

Subtances Sucrose solution

Observation With no hydrolysing  No colour change With hydrolysing  The solution’s colour changes from blue to green to yellow and finally to brick-red

Details Sucrose is disaccharide that does not reduce copper sulphate. Therefore, it should be hydrolysed into its constituent monosaccharides before testing it with benedict’s reagent. Sucrose then will react with Benedict's reagent to reduce the blue copper (II) ion to form a brick red precipitate of copper (I) oxide.

E. CELLULOSE Reagent Schultz’ solution

Subtances Cotton wool

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Observation Cotton is high of cellulose. Therefore it should be stained to purple. However, the changes of colour of cotton are not clear. When the solutions tested on a plant tissue and observed under microscope cell walls of the tissue is purple in colour

Details Schultz’ solution reacted with cellulose to produced purple stained. In the experiment, when the reagent is put on the cotton and also in the solution, both of the produce purplecoloured stains indicating that both of them possess cellulose.

F. LIGNIN Reagent Acidified phloroglucinol

Subtances Wood

Observation  When tested on toothpick, colour of toothpick becomes red  When solution is tested on plants item, colour of xilem seen to be red in colour

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Details Acidified phloroglucinol can react with lignin to produce red stain. After testing with toothpick and xilem, both of them stained red indicating that both of them contain lignin.

G. LIPIDS Reagent

Substances

Sudan Ш

Oil palm and water

Sudan Ш

Pure oil and palm oil

Ethanol

Palm oil and water

Observation Colour (initial) Colour (final)  Two  Two layers are separate formed layers are  Top red and formed bottom dark red  The top one yellow (oil) the bottom colourless (water)  The oil palm  The red settles is pale at the base of yellow in the test tube, colour whilst the top layer is a dark  The entire yellow with red solution is droplets red in colour suspended in it  Initially clear,  A thin top, layer slightly of cloudy, light cloudy when yellow, water is added followed by a long rung of cloudy white and a thin bottom layer of dear yellow

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Details Basically, when Sudan III reacted with lipid, a red-stained oil layer separate out and floats on the water surface.

Ethanol reacted with lipids to form a cloudy white precipitate. In the experiments, cloudy white precipitate formed after some time representing that the palm oil contained lipid.

H. PROTEIN Reagent Millon’s reagent

Substances  Albumen

Observation Details  Brick-red precipitate appears. Millon tests for phenolic -OH group  Pea  Before heated, the sample present in sample such was creamy white in colour. as protein. Millon’s However, after heated, the reagent is prepared colour of the sample change from mercuric and mercurous nitrate in to yellowish browning. nitric acid. When protein is heated with Millon's reagent, a white precipitate is formed and on heating changes to brick red. Xanthoproteic  Nitric Xanthoproteic Acid  The solution’s colour which test Test tests R Group. acid is deep-yellow disappears. This is a test for specific functional groups that a positive test is formation of a deep-yellow orange or orange-red color. A deep-yellow partial precipitate, which disappears, on shaking, indicates protein. Biuret test Biuret array is a test for  Potassium  A blue ring appears at the peptide bonds present hydroxide surface of the solution. in the sample such as  On shaking, the blue ring protein. Under alkaline disappears. conditions, peptide  The solution’s colour turns bonds are cleaved and purple react with a copper reagent to yield a purple colour.

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I. INVESTIGATING UNKNOWN Reagent Dilute iodine

Benedict reagent

Schultz’s solution

Component  Content

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Observation No colour changes spotted. The solution remains yellow No colour changes spotted. The solution remains yellow No colour changes spotted. The solution remains yellow

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Husk

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Seeds

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Content

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The solution’s colour changes from blue to green to yellow to brick-red

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Husk

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Seeds

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The solution’s colour changes from blue to green to yellow to brick-red The solution’s colour changes from blue to green to yellow to brick-red

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Content

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Husk

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Seeds

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Content

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Acidified  phloroglucinol

The solution’s colour changes from colourless to purple No colour changes spotted. The solution remains colourless. No colour changes spotted. The solution remains colourless. No colour changes spotted. The solution colour remains red.

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Details Basically, if starch is mixed with iodine in water, an intensely colored starch/iodine complex is formed. However, when iodine is dropped into the unknown solution, no colour changes which is from yellow to blue-black is spotted. Therefore, there is no starch in the unknown. When benedict reagent is dropped into the unknown solution, the colour changes. This mean the unknown do has glucose/carbohydrates in it. This is because Carbohydrates react with Benedict's reagent to reduce the blue copper (II) ion to form a brick red precipitate of copper (I) oxide. Even so, the unknown solution does not have sucrose in it because red-brick precipitate can be obtained without hydrolysing it. Cellulose stained purple with Schultz’ solution. Then, when the reagent is being tested with the unknown solution, the solution’s colour changes from colourless to purple. For this reason, the unknown should comprise cellulose in it. Acidified phloroglucinol can react with lignin to produce red stain.

Sudan III

Millon’s reagent

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Husk

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Seeds

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Content

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Husk

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Seeds

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Content

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Husk

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Seeds

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However, not all structure in the unknown actually reacted with the reagent to produce red stained. Only certain part such as content and husk stained red with the reagent The solution changes Fundamentally, a redstained oil layer that colour from paint separate out and float on yellow to blurred the water surface indicates red. the existence of lipid in the No colour changes spotted. The solution solution. Still, when Sudan remains paint yellow III is added up to the solution, a blurred redNo colour changes spotted. The solution stained oil layer appears. remains paint yellow This mean, there is not much lipid exist in the unknown. The solution’s colour Hypothetically, when protein is heated with changes from colourless to blurred Millon's reagent, a white precipitate is formed and brick-red on heating changes to No colour changes spotted. The solution brick red. However, when the unknown is heated, a remains colourless. The solution’s colour blurred brick-red precipitate produced, changes from colourless to blurred meaning that the amount of protein in the unknown brick-red is not much. No colour changes spotted. The solution colour remains red. The solution changes colour from red to colourless.

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PART 2

Chemical compound Fructose

Lignin

Protein

Reagent

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Benedict’s reagent

Sudan III

Millon’s reagent

Observation Title: Light photomicrograph drawing of cell of apple

Magnification: x100 Title: Light photomicrograph drawing of xilem of plant stem

Magnification: x100 Title: Light photomicrograph drawing of cell of pea

Magnification: x100

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Unknown

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Benedict’s reagent

Sudan III

Millon’s reagent

Title: Light photomicrograph drawing of unknown cell

Magnification: x100 Title: Light photomicrograph drawing of unknown cell

Magnification: x100 Title: Light photomicrograph drawing of unknown cell

Magnification: x100

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PART 3 Conclusion 1. Potato tuber contained starch because the dilute iodine change colour from yellow to blue-black 2. Apple contained glucose and sucrose when brick red precipitates appear when tested with benedict’s reagent 3. Apple contained fructose because the cells change colour from blue to brown after heated 4. Stem cells containing cellulose since the cell stained in purple. 5. Stem cells contained lignin since the cell stained red in colour. 6. Oil palm seeds contained lipids 7. Albumen and pea contained lipid because brick red precipitate appears when tested with Millon’s reagent. 8. For the unknown test, the unknown contained high concentration of fructose, glucose and sucrose because brick red precipitates appear when tested with Benedict’s reagent. However, apple contained low quantity of cellulose and lignin since the change of colour of the indicators are blurred. Apple also contained low quantity of lipid and protein.

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