Galactose and Fructose are called isomers of glucose. Why?
All three have the molecular formula C6H12O6. However, their connectivity in space varies for each.
Galactose and fructose are called isomers of glucose because they have the same molecular formula, C6H12O6, but their atoms are arranged differently. Isomers are compounds that have the same number and types of atoms, but different structural arrangements.
To understand why galactose and fructose are isomers of glucose, we need to look at their chemical structures. Glucose, galactose, and fructose are all monosaccharides, which are simple sugars.
Glucose has a linear structure with an aldehyde functional group. It has a six-membered ring structure, known as a pyranose ring, where oxygen from the aldehyde group forms a bond with one of the carbon atoms in the chain.
Galactose, on the other hand, has a very similar structure to glucose, with the same six carbon atoms arranged in a chain. However, the positions of hydroxyl groups (-OH) on carbon atoms 4 and 6 are different. This subtle difference gives galactose its distinct chemical structure.
Fructose, on the other hand, has a different structure. It also has a six-carbon chain, but it forms a five-membered ring structure, called a furanose ring, with oxygen atoms from both the aldehyde and hydroxyl groups.
So, galactose and fructose are isomers of glucose because they have the same molecular formula but different arrangements of their atoms, resulting in distinct chemical structures and properties.