The colored balls are other groups with many, many possibilities such as methyl, ethyl, chlorine, benzene ring, etc. All the representations of sugar structures are distortions as the spatial arrangements are forced to the plane of the computer terminal. Consider looking down at pyramids that have a yellow group bonded to the top. The black group is at the back of each. Sugars have several asymetric carbon atoms.
Sugars differ in reactivity, and in properties such as solubility and sweetness.
Let's learn a quick way to draw sugars. A stick will represent the chain of carbons. An arrow head stands for the aldehyde group. How to remember pentose structures.