Question

Define the terms (a) pyranose and (b) furanose.

Short answer

Answer: Pyranose and furanose are two structural forms of carbohydrates. The main differences between them lie in their ring structures. A pyranose has a six-membered ring structure resembling pyran, with five carbon atoms and one oxygen atom. An example of a common pyranose is glucose. On the other hand, a furanose has a five-membered ring structure resembling furan, with four carbon atoms and one oxygen atom. An example of a common furanose is fructose. Both pyranose and furanose forms can have various substituent groups like hydroxyl (-OH) or other monosaccharides.

Step-by-step solution

Background on Carbohydrates

Carbohydrates are important biomolecules needed for energy storage, cellular communication, and structural support. They consist of carbon, hydrogen, and oxygen atoms, and play significant roles in living organisms. Two common structural forms of carbohydrates are cyclic, which are called pyranose and furanose.

(a) Pyranose Definition

A pyranose is a carbohydrate with a structure resembling a six-membered pyran ring. It contains five carbon atoms and one oxygen atom in its ring structure. The pyranose ring may also have various substituent groups like hydroxyl (-OH) or other monosaccharides. Pyranose forms are derived from aldoses and ketoses through hemiketal or ketal formation. An example of a common pyranose is glucose.

(b) Furanose Definition

A furanose is a carbohydrate with a structure resembling a five-membered furan ring. It contains four carbon atoms and one oxygen atom in its ring structure. Like pyranose, the furanose ring may also have various substituent groups like hydroxyl (-OH) or other monosaccharides. Furanose forms are derived from aldoses and ketoses through hemiketal or ketal formation. An example of a common furanose is fructose.