Question

Which of the following is an example of an aldopentose?
(A) D-Ribose
(B) Glyceraldehyde
(C) Fructose
(D) Erythrose

Answer 1

Hint:Understand what is meant by aldopentose then you can easily solve this question.you can understand this from the name itself aldo = aldo + pentose that is aldo is refer to aldehyde group with pentose.

Complete step-by-step answer: Aldopentose by definition is a pentose with an aldehyde functional group attached to the first carbon atom: a pentose (such as ribose or arabinose) of an aldehyde nature. It is a naturally occurring monosaccharide with a carbonyl group located at the end of its 5-carbon chain, making it an aldehyde derivative, or an aldopentose.Now let us know about each of the option which we are given with:
D-ribose is an energy producing substrate of the ATP molecule and is often called the
“molecular currency” because of its role in intracellular energy transfer. Adenosine triphosphate consists of phosphate, ribose, and adenosine groups that are connected through two high-energy phosphoanhydride bonds within the molecule. As a pentose sugar, D-ribose has five carbons in its ring structure.Now let us know about Glyceraldehyde (glycerol) is a triose monosaccharide. It is the simplest of all common aldoses. Fructose, or fruit sugar, is a simple ketonic monosaccharide found in many plants, where it is often bonded to glucose to form the disaccharide sucrose.At last, Erythrose is a tetrose saccharide with the chemical formula C4H8O4. It has one aldehyde group, and is thus part of the aldose family. The natural isomer is D-erythrose.Hence we can conclude simply as:
D-Ribose → Example of aldopentose.
Glyceraldehyde → Example of aldotriose.
Fructose → Example of aldohexose.
Erythrose → Example of aldotetrose.

Hence, (A) is the correct answer.

Note: One term here which has to be taken into consideration is Monosaccharides. Monosaccharides are simple sugars in which there are one oxygen atom and two hydrogen atoms for each carbon atom present in the molecule. Monosaccharides are also known to be reducing sugars.