What specific molecule for animal and plant structure?

The specific molecules that provide structure for animals and plants are:

Animals:

1. Collagen: The main structural protein found in connective tissues such as skin, tendons, ligaments, and bones.

2. Elastin: A flexible protein that allows tissues to stretch and recoil, found in arteries, lungs, and skin.

Plants:

1. Cellulose: A polysaccharide found in plant cell walls, providing strength and rigidity.

2. Hemicellulose: Another type of polysaccharide that helps cross-link cellulose fibers and provides flexibility.

3. Lignin: A rigid, aromatic polymer that reinforces the cell walls of wood and other vascular plants.

4. Pectin: A polysaccharide that helps bind plant cell walls together and plays a role in plant growth and development.