Final answer:
Orange juice is primarily composed of the simple sugar glucose, which is a monosaccharide and significant energy source. Other sugars like fructose are also present, contributing to the juice's sweetness. Starch and cellulose are complex carbohydrates also based on glucose, but they serve different functions in plants.
Step-by-step explanation:
The specific molecule that orange juice is mostly made of is glucose. Orange juice primarily contains simple sugars, with glucose being one of them. In fruits such as oranges, fructose is also present alongside glucose, and it is the sugar fructose that contributes to the sweetness. Glucose is a monosaccharide, which is a type of simple sugar, and is a crucial source of energy for living organisms.
When discussing carbohydrates in the context of biology and nutrition, it's important to note that they can be simple sugars like glucose and fructose or complex carbohydrates like starch and cellulose. Starch is a polysaccharide that plants use to store energy, and it is made of multiple glucose units. On the other hand, cellulose is another polysaccharide made of glucose that constitutes the structural component of plant cell walls and is what gives cotton its strength.