Final answer:
Sucrose is formed through dehydration synthesis, which involves the combination of glucose and fructose while removing a water molecule. Water is a key by-product of this process.
Step-by-step explanation:
The process required to form a sucrose molecule is called dehydration synthesis. In this process, a molecule of glucose and a molecule of fructose combine to produce a disaccharide sucrose. This reaction involves the removal of a water molecule. One key by-product of this process is water. As a water molecule is lost during the formation of the glycosidic bond between glucose and fructose, water is produced as a by-product.