Question

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

Short answer

Question: Define and differentiate between pyranose and furanose in the context of carbohydrates. Answer: Pyranose and furanose are terms used to describe the cyclic forms of sugars. Pyranose refers to the cyclic form of a sugar with a six-membered ring structure, consisting of five carbons and one oxygen atom, such as in glucose. Furanose refers to the cyclic form of a sugar with a five-membered ring structure, consisting of four carbons and one oxygen atom, such as in ribose and deoxyribose. Both pyranoses and furanoses exist in two anomeric forms (alpha and beta) due to the configuration of the hydroxyl group on the first carbon in the ring.

Step-by-step solution

(a) Definition of Pyranose

Pyranose is a term used to describe the cyclic form of a sugar that has a six-membered ring structure, consisting of five carbons and one oxygen atom in the ring. This term gets its name from a six-membered cyclic compound called pyran. The most common pyranose structure is found in glucose. It is important to note that pyranoses exist in two anomeric forms (alpha and beta) due to the configuration of the hydroxyl group on the first carbon in the ring.

(b) Definition of Furanose

Furanose is a term used to describe the cyclic form of a sugar that has a five-membered ring structure, consisting of four carbons and one oxygen atom in the ring. This term gets its name from a five-membered cyclic compound called furan. The most common furanose structure is found in ribose and deoxyribose, which are the sugar components of RNA and DNA, respectively. Like pyranoses, furanoses also exist in two anomeric forms (alpha and beta) due to the configuration of the hydroxyl group on the first carbon in the ring.