What is aD-2-ketopentoses?

Answer 1

This is a carbohydrate with a ketone functionality made of 5 carbons. The second carbon has a double bond to oxygen, hence the 2. The D just means that the highest number C has an OH on the right side when drawn in a fisher projection.

Answer 2

2-Ketopentoses are a type of carbohydrate composed of five carbon atoms with a ketone group at the second carbon position. They are involved in metabolic pathways such as the pentose phosphate pathway and can be found in nucleic acids and certain microorganisms.