Starch, cellulose and hydrogen bonding

If you look at the image below you will see alpha glucose molecules linked to form a section of starch. Most of the OH groups capable of forming hydrogen bonds, colored in red, project inwards. So little hydrogen bonding can occur between the polymers of starch which is the reason why it lacks the structural properties of cellulose.
If you look at the image below you will see beta glucose molecules linked to form a section of cellulose. Most of the OH groups capable of forming hydrogen bonds, colored in red, project from both sides of the chain. This results in bundles of very tightly held parallel chains of cellulose.

Below is an animation showing where hydrogen bonding occurs along the length of a cellulose chain.

The strength of the covalent bonds withing the polymer chain and the hydrogen bonding between the chains makes cellulose a strong structural material. Up to 2,000 cellulose chains are packed together to form microfibrils, which are packed in overlapping layers, as shown on the right.

The cell wall of a plant cell is composed of cellulose.The polymers are strongly hydrophilic, water loving, which allows the cell wall to become saturated with water, much like a sponge.

Glycogen

Home