Glucose – a sweet crystal structure

What are we looking at?

This Photo by Unknown Author is licensed under CC BY-SA-NC

Did you know that sugar is actually made out of lots of different types of molecules?  Glucose is a ‘monosaccharide’ and one of the three building blocks of all edible sugars, along with fructose and galactose.

Other sugars, such as lactose and sucrose, are actually made up of two sugars molecules attached together, for instance sucrose is made from one glucose and one fructose.  During digestion we break down these molecules into their simpler parts, like glucose, which then gets absorbed into our blood.   There it is used by proteins in our bodies, such as the glucose transport proteins, which helps supply our brains with energy to work.

Sugar molecules can build in many ways, and even form larger structures.  One example of this is cellulose which is the most abundant natural polymer on Earth, and is made up of glucose molecules joined together into long chains. It is a key component of plant materials, for example 40-50% of wood is cellulose.

How do we actually know that glucose molecules are arranged like this?

This Photo by Unknown Author is licensed under CC BY-SA-NC

Because most molecules are made up of light atoms (those at the top of the periodic table) for many years finding the crystal structure of these materials was very tough.  Now with modern techniques it is pretty routine, and scientists use crystals of glucose (which are easily grown) to test their instruments out.