Carbohydrate Identification Lab

Lab

1. Label 3 test tube Mono, Di , and Polysaccharide
2. Get an dropper and hot water(keep water hot)
3. In each tube with the dropper pour the labeled substance 
1. Liquid should be clear
4. Take the Benedict (blue liquid) and using the dropper pour till clear substance turns blue
5. Move all three tubes into hot water and let sit for at least five minutes
1. Watch for a reaction from each substance
6. Write down your observations
7. After five minutes remove tubes
8. After writing result rinse and dry tubes for next test
9. repeat step 1 and 2
10. This time instead of Benedict (blue) you will use the dropper to pour Iodine
11. repeat steps 5 through 8

 Analysis Questions

1.     Name the three categories of carbohydrates studied in this
 investigation.

            Mono, Polysaccharide, Di

2.     What three elements are present in all carbohydrates?

            Carbon, Hydrogen, Oxygen

           

3.     Give two examples each of sugar molecules from our 
discussion or the textbook that are:

a.     Monosaccharides: Glucose,Galactose,Fructose

b.     Disaccharides:Lactose, Sucrose,

c.     Polysaccharides: Starch, Cellulose,Glycogen 

4.     How many times larger is the number of hydrogen atoms than oxygen atoms in:

a.     Water:ratio of 2:1(hydrogen 2, oxygen 1)

b.     Carbohydrates: 2:!(hydrogen 2, oxygen 1)

5.     “Mono” means one, “di” means two, and “poly” means many. Why are these terms used
 in describing the three types of sugars?

            Theses terms (Mono, Di, Poly) are used to describe the three 
types of sugar because it tells you how many sugar molecules there are.

6.     How can you tell by using Benedict’s and iodine solutions if a sugar is a

a.     Monosaccharide

            Benedict:The Mono reacted by turning green and then three minutes
 later turned brown, and after five minutes turned orange.

            Iodine:Turned red but no reaction

b.     Disaccharide

            Benedict:No reaction

            Iodine:Tured Red no reaction

c.     Polysaccharide

            Benedict:No reaction

            Iodine:Reacted right away by turning black

7.     A certain sugar has no change in color when tested with Benedict’s solution.

a.     Can you tell what type of saccharide it is?

            Polysaccharide

b.     Explain

            There was no chemical reaction

8.     A certain sugar has a color change in Benedict’s solution.

a.     Can you tell what type of saccharide it is?

            Monosaccharide

b.     Explain.

            Mono first reacted by turning green then precced to turn 
brown and last orange

9.     Give an example of a food that contains

a.     Monosaccharides

            Ex.Soda, Candy, Fruit

b.     Disaccharides

            Ex. Table Sugar

c.     Polysaccharides

            Ex.Pasta, Bread, Starch