Aldoses are a type of simple sugar, or monosaccharide, characterized by the presence of an aldehyde group (-CHO) in their molecular structure. They are important in biology as they serve as energy sources and building blocks for more complex carbohydrates. Common examples of aldoses include glucose and galactose. In terms of their chemical structure, aldoses can vary in the number of carbon atoms they contain, typically ranging from three to seven. The classification of aldoses is based on the number of carbons, such as trioses (three carbons) and pentoses (five carbons).