Question

The sweet taste of honey id because the monosaccharides D-glucose and D-fructose. What are some differences in the Fischer projections of D-glucose, D-galactose, and D-fructose? write 150 words provide 2 sources, i.e. journal articles, books, etc.

Answer 1

What are Monosaccharides?

An easiest form form of Sugar, which is also a basic unit of Carbohydrates are called Monosaccharides. As it is simpler in nature, they cannot be converted into more simple units by hydrolysis. General properties of Monosaccharides are

1) Water Soluble

2) Colorless

3) Crystalline Solids

Typical Formula for Monosaccharides is C_nH_2nO

Most familiar Monosaccharides are

a) Glucose

b) Fructose

c) Galactose

These Monosaccharides differ in their Fischer Projections.

What is Fischer Projection?

Carbohydrates can be represented by Fischer Projection. The top position is occupied by the most oxidised group. Chiral carbon is exhibited in the intersection of vertical lines and horizontal lines. Horizontal intersecting lines is for H groups and OH groups. CH₂OH group will be in the bottom, which is not chiral.

What are the D and L notation stands for?

By consdering L and D as isomers in which the OH group of the chiral carbon is far away from the carbonyl group. The letter 'L' is for left and 'D' is for Right.

Fischer Projections of Monosaccharides

For D - Glucose

т со СН2ОН D - Glucose .

For D - Fructose

CH2OH OH CH20lt D- Fructose.

For D - Galactose

СН2ОН D- Galactose

Each Monosaccharides has the same Molecular Formula C₆H₁₂O₆ .

According to D - Glucose, C - 1 has an aldehyde group, and C -2 has a Secondary alcohol, it is a aldol hexose, which is dextrorotatory

For D - Fructose, C - 1 has a Primary alcohol, and C - 2 has a Ketone, it is a Keto hexose which is levorotatory.

For D- Galactose, it is an aldol hexose, which shows the properties of both levorotatory and dextrorotatory.