Question

Help me out real quick for a medal?

What makes fat and starch more stable in comparison to ATP?

Answer 1

By "stable", i assume you mean "non-hydrolyzable".

Look at the phosphoanhydride bonds in ATP; the negative charges on the atoms that the oxygens bear are close together. You know that like-charges cause a repulsive force on one another, so these oxygens so close together have a lot of potential energy that is only relieved by removing a phosphate group from the branch - that is removing it by hydrolysis.

Fats and starch have very different chemical compositions. Fats for the most part are hydrocarbons; these cannot be hydrolyzed as there aren't any polarizing groups or other groups that aid in reactivity. Starch is a polymer of glucose; this CAN be easily hydrolyzed into individual monosaccharides in the presence of acid, but cannot be broken down any further.

I'm not sure if this is the type of answer you are looking for.

Answer 2

This actually helped me more than I thought any answer would... @aaronq, you are amazing!!

Answer 3

good stuff !