Brad was provided with a piece of bread and egg yolk. He wants to know which component is present in the given food. Suggest him the scientific procedures to find the right component present in each food item.

 Please see explanation column

Explanation:

Sample provided to Brad = a piece of bread and egg yolk

1. We know that Bread is a carbohydrate containing starch  

To investigate the presence of starch/ Carbohydrate  in Bread

Materials: Bunsen burner,test tubes, food product -Bread,iodine solution

Method

1. Place a sample of bread  into the test tube.  

2. Place a few drops of iodine solution on the bread

3. Take  observations.

4. Wait a few more minutes and note any other changes.

Observations

On addition of iodine to the bread , if we notice a blue-black  coloration,  we will conclude that the right component found in bread is starch /carbohydrate

The above procedure can also be confirmed using

-Molisch’s reagent–which gives us a purple or violet color ring on addition to the bread

- Fehling’s reagent  –which gives a Red precipitate to indicate  the presence of  in the bread

-Benedict’s reagent  –which gives  Red precipitate to indicate  the presence of carbohydrates in the bread.

-Tollen’s reagent – which gives us Silver mirror to  confirm the presence of carbohydrate in the bread.

2. We know that egg yolk contains protein,

To investigate the presence of Protein  in egg yolk using biuret test

Materials: Bunsen burner,test tube, food product -egg yolk ,   Aqueous copper sulfate solution

Method

1. Place a sample of egg yolk   into the test tube.  

2. Place a few drops of  Aqueous copper sulfate solution  on the sample of egg yolk

3. Note observations.

4. Wait a while and  note any other changes.

Observations

On addition of Aqueous copper sulfate to the egg yolk  , if we notice a violet coloration,we will conclude that the right component found in egg yolk is protein

The above procedure can also be confirmed using

Xanthoproteic test – which on addition of  Nitric acid to the egg yolk gives a Yellow coloration

Millions test – which on addition of  Mercuric sulfate in the presence of sodium nitrite and sulfuric acid to the sample of egg yolk gives  Brick red color solution confirms the presence of proteins.

Ninhydrin test – which on addition of  Pyridine solution of ninhydrin to the sample of egg yolk gives  Violet color solution confirms the presence of proteins.

which condition is a cause of impotency in men?

b. the inability of the penis to become erect