Question

Sketch a representation of the disaccharide sucrose (table sugar). Label clearly the portion of the disaccharide that originates from glucose, the portion that originates from fructose, and the glycoside linkage between the rings.

Short answer

To sketch the disaccharide sucrose (table sugar), first draw the ring structures of glucose (a hexagon) and fructose (a pentagon), including all carbon, oxygen, hydrogen, and hydroxyl (-OH) groups. Create a glycoside linkage between the first carbon atom of glucose and the second carbon atom of fructose by removing a hydrogen atom from the hydroxyl group on the first carbon of glucose and a hydroxyl group from the second carbon of fructose. Form a bond between these two carbon atoms, writing "Glucose" next to the hexagonal ring, "Fructose" next to the pentagonal ring, and "Glycoside Linkage" between the two rings.

Step-by-step solution

Draw the ring structure of glucose

Glucose is a monosaccharide and has the chemical formula C6H12O6. It has a cyclic structure with a six-membered ring containing five carbon atoms and one oxygen atom. The ring structure of glucose is drawn as follows: 1. Draw a hexagon for the six-membered ring. 2. Add the oxygen atom to one corner of the hexagon. 3. Place the remaining five carbon atoms around the rest of the hexagon. 4. Determine the position of the hydroxyl (-OH) and hydrogen (-H) groups for each carbon in the ring. 5. Attach an additional carbon atom to the fifth carbon to complete the glucose structure. #step_2#

Draw the ring structure of fructose

Fructose is another monosaccharide and has the chemical formula C6H12O6, just like glucose. However, it has a slightly different cyclic structure with a five-membered ring containing four carbon atoms and one oxygen atom. The ring structure of fructose is drawn as follows: 1. Draw a pentagon for the five-membered ring. 2. Add the oxygen atom to one corner of the pentagon. 3. Place the remaining four carbon atoms around the rest of the pentagon. 4. Determine the position of the hydroxyl (-OH) and hydrogen (-H) groups for each carbon in the ring. 5. Attach two additional carbon atoms to the second carbon, and one to the fourth carbon to complete the fructose structure. #step_3#

Connect glucose and fructose rings to form sucrose

To form the disaccharide sucrose, glucose and fructose must be connected through a glycosidic linkage. The glycoside linkage is formed between the first carbon atom of glucose and the second carbon atom of fructose. In this process, water is eliminated, and a covalent bond is formed. Follow these steps: 1. Align the glucose and fructose rings so that the hydroxyl groups attached to the first carbon of glucose and the second carbon of fructose are next to each other. 2. Remove a hydrogen atom from the hydroxyl group on the first carbon of glucose and a hydroxyl group from the second carbon of fructose. 3. Form a bond between the first carbon of glucose and the second carbon of fructose. This bond is the glycoside linkage. #step_4#

Label the sections of sucrose

We now have the complete structure of sucrose. To finish the exercise, we need to label the glucose, fructose, and glycoside linkage. Follow these steps: 1. Write "Glucose" next to the six-membered ring of glucose. 2. Write "Fructose" next to the five-membered ring of fructose. 3. Label the glycoside linkage between the two rings as "Glycoside Linkage." This completes the sketch of the disaccharide sucrose, with all the required portions labeled clearly.