Sucrose Synthesis
Sucrose Synthesis by D. DeWitt, PhD v1.5 11/10/12 Introduction | Condensation
Reaction | Plant Synthesis |
A. Introduction
Although it might seem straight forward, the synthesis of sucrose, either as a simple condensation reaction (a.k.a. dehydration synthesis), or what actually happens in plants is complicated.
Before we explore sucrose's creation, let's take a look at its structure. In Figure 1, the space-filling model is pretty but rather useless at this point in our journey. We need to see the atoms! | Figure 1: Space-filling Model of Sucrose
(Click on image to visit originating website.) | In Figure 2, you will find the structural formula for sucrose. It is a disaccharide made from the simple sugars glucose (on the left) and fructose (on the right).
I will caution you right now that there are many different view of sucrose on the internet, so if this one does not agree with your impression, there are reasons: 1) errors (e.g., Fructose has 7 oxygens) and 2) synthesis from different forms (isomers) of glucose and fructose. |
Figure 2: Structural Model of Sucrose
Note: Carbon atoms are assumed at all angles of each geometric shape (hexagons and pentagons) unless an atom is shown (e.g. oxygen)
(Click on image to visit originating website.) | The first issue is the process by which two sugars can be chemically joined. | The answer is found in the fact that these sugars are literally covered with hydroxyl (-OH) groups. As shown in Figure 3 on the right, a hydroxyl group on one sugar (-OH) can be connected to another hydroxyl group (HO) on a second sugar by removing an -OH from the first sugar and a H- from the second leaving a -O- bond connecting the two sugars in a disaccharide.
In addition, the released -OH and H- join to form H2O (HOH). The name of the -O- bond is called a glycosidic bond. The bond gets its name from the fact that the disaccharide is also called a glycoside. | sugar1-OH + HO-sugar2
sugar1- +
Reaction | Plant Synthesis |
A. Introduction
Although it might seem straight forward, the synthesis of sucrose, either as a simple condensation reaction (a.k.a. dehydration synthesis), or what actually happens in plants is complicated.
Before we explore sucrose's creation, let's take a look at its structure. In Figure 1, the space-filling model is pretty but rather useless at this point in our journey. We need to see the atoms! | Figure 1: Space-filling Model of Sucrose
(Click on image to visit originating website.) | In Figure 2, you will find the structural formula for sucrose. It is a disaccharide made from the simple sugars glucose (on the left) and fructose (on the right).
I will caution you right now that there are many different view of sucrose on the internet, so if this one does not agree with your impression, there are reasons: 1) errors (e.g., Fructose has 7 oxygens) and 2) synthesis from different forms (isomers) of glucose and fructose. |
Figure 2: Structural Model of Sucrose
Note: Carbon atoms are assumed at all angles of each geometric shape (hexagons and pentagons) unless an atom is shown (e.g. oxygen)
(Click on image to visit originating website.) | The first issue is the process by which two sugars can be chemically joined. | The answer is found in the fact that these sugars are literally covered with hydroxyl (-OH) groups. As shown in Figure 3 on the right, a hydroxyl group on one sugar (-OH) can be connected to another hydroxyl group (HO) on a second sugar by removing an -OH from the first sugar and a H- from the second leaving a -O- bond connecting the two sugars in a disaccharide.
In addition, the released -OH and H- join to form H2O (HOH). The name of the -O- bond is called a glycosidic bond. The bond gets its name from the fact that the disaccharide is also called a glycoside. | sugar1-OH + HO-sugar2
sugar1- +