why is cellulose stronger than amylose?

Answer 1

It has to do with the three dimensional structures and the ways the glucose monomers are joined to form the polymers, cellulose or amylose. Bear in mind, however, that the glucose has a lot of hydroxyl groups (OH) capable of hydrogen bonding.

In cellulose, the linkings of the monomer units is through what is called a beta 1 to 4 linkage, (refer to your organic chemistry text). In any case, this particular conformation or "orientation" lends itself to a straight, rod like structures exposing all the hydroxyl groups to hydrogen bond with all its neighboring polymer units.

On the other hand, the linkings in amylose is through alpha 1 to 4 linkage. This will allow more coiling of the polymer making for a helical structure. This structure is less rigid and less strong than cellulose's. That is why cellulose is found a lot more in those weight bearing trees and plants.

This is a classic case of the connection between chemical 3-D structure with function.

Answer 2

The biological structure. Amylose has fewer branches than cellulose. See information on their biological structures below:

Answer 3

Basic morphology. Cellulose has a "grain" to it when in large-enough quantities. Amylose is more globular, almost amorphous and less cohesive, that's why it's a snap for Amylase to break it down.