The aldoses

Linear D-aldoses

For the aldoses L , the penultimate hydroxide group is oriented to the left in the projection of Fischer, eg:

Mnemonic technique to retain aldohexoses (it is necessary to see how the $ -OH $ follow each other regularly!):

All Altruists Gladly Make Gum In Gallon Tanks. (en)

Allez Altruistes Glaner la Manne, Gustave Ira Garder les Taureaux. (fr)

Alle Alten Gänse Möchten, Gut Im Garten Tanzen. (de)

Presentation of some aldoses


Glucose is a white solid with a sweet flavor. It is soluble in water and crystallizes above a concentration of $ 30\% $. It is directly assimilable by the organism and its degradation provides energy. The blood glucose level (blood glucose) is normally stable in the body. Its normal value is between $ 0.74 \frac{g}{L} $ and $ 1.16 \frac{g}{L} $.


Characterized by a strong sweetening power, fructose is abundant in fruits and honey.


It is a sugar present in the milk of mammals in the form of lactose whose hydrolysis by the enzyme $ \beta $-galactosidase gives glucose and galactose.


It is characterized by its high solubility in water. Some of its derivatives are important in biochemistry.

The ribose

Ribose enters into the constitution of ribonucleic acids ($ RNA $), adenosine triphosphate ($ ATP $) and other important molecules in biochemistry.