Chem31a BIOCHEMISTRY Experiment 3

DEPARTMENT OF PURE AND APPLIED CHEMISTRY
Visayas State University, Baybay City, Leyte
CHEM31a – BIOCHEMISTRY
Laboratory Report

Name: Alyssa Diane Marie L. Baljon Date Performed: May 7, 2015
Course & Year: BSChem 2 Date Submitted: May 11, 2015
Lab Schedule: M-F 7:00-10:00 Score:
Group No. 4

Experiment No. 3
Carbohydrates

Objectives
Use of chemical tests to identify some physical and chemical characteristics of typical carbohydrates.
Differentiate between monosaccharides, disaccharides, and polysaccharides using above tests
Identify an unknown carbohydrate

Results

A. STRUCTURAL FORMULAS FOR CARBOHYDRATES
MONOSACCHARIDES
STRUCTURES

FISCHER
HAWORTH
CHAIR
Glucose

Fructose

DISACCHARIDES (Haworth and Chair structures only)
Lactose

Sucrose

HAWORTH CONFORMATION

HAWORTH CONFORMATION

CHAIR CONFORMATION

CHAIR CONFORMATION
Maltose

HAWORTH CONFORMATION

CHAIR CONFORMATION

POLYSACCHARIDES
Amylose

CHAIR CONFORMATION

HAWORTH CONFORMATION
Glycogen

B. BENEDICT’S TEST FOR REDUCING SUGARS
Compound
Color
Reducing Sugar (yes/no)
Water
Blue
No
Glucose
Red
Yes
Fructose
Reddish-Orange
Yes
Sucrose
Blue
No
Lactose
Red
Yes
Maltose
Red
Yes
Starch
Blue
No
Glycogen
Blue
No

C. BARFOED’S TEST FOR MONOSACCHARIDES
Compound
Color
Monosaccharides (yes/no)
Water
Blue
No
Glucose
Red
Yes
Fructose
Red
Yes
Sucrose
Blue
No
Lactose
Blue
No
Maltose
Blue
No
Starch
Blue
No
Glycogen
Blue
No

D. SELIWANOFF’S TEST FOR KETOHEXOSES
Compound
Color
Ketohexoses/Aldohexoses
Water
Light-Orange
Aldohexoses
Glucose
Light-Orange
Aldohexoses
Fructose
Brown
Ketohexoses
Sucrose
Brown
Ketohexoses
Lactose
Light-Orange
Aldohexoses
Maltose
Light-Orange
Aldohexoses
Starch
Light-Orange
Aldohexoses
Glycogen
Light-Orange
Aldohexoses

E. IODINE TEST FOR POLYSACCHARIDES
Compound
Color
Polysaccharides (yes/no)
Water
Orange
No
Glucose
Orange
No
Fructose
Orange
No
Sucrose
Orange
No
Lactose
Orange
No
Maltose
Orange
No
Starch
Black
Yes
Glycogen
Black
Yes

F. HYDROLYSIS OF DI- AND