All Biochemistry Resources
Example Questions
Example Question #31 : Identification By Structure
Identify the carbohydrate class of the given molecule.
Ketopentose
Aldohexose
Aldopentose
Ketohexose
Ketoquintos
Ketopentose
The structure is a ketopentose. Keto- refers to the ketone at the second carbon and pentose refers to a carbohydrate with five carbons.
Example Question #32 : Identification By Structure
Identify the given structure.
D-galactose
D-glucose
D-fructose
L-galactose
L-glucose
D-glucose
This ring structure is of D-glucose. The hydroxyl group on the first carbon (the carbon to the bottom right of the oxygenin the ring) can face either down (the alpha conformation) or up (the beta conformation). Note that the beta conformer is more thermodynamically stable since all the hydroxyl groups on the ring would be in the equitorial position, thus minimizing steric hinderance and intramolecular electrostatic repulsion.
Example Question #33 : Identification By Structure
Identify the given structure.
D-glucose
D-mannose
D-galactose
D-ribose
D-fructose
D-fructose
This is the ring/cyclic structure of D-fructose.
Example Question #31 : Identification By Structure
Which of the following is the correct structure of a disaccharide?
Maltose = glucose + glucose
Lactose = galactose + galactose
Lactose = galactose + fructose
Maltose = sucrose + fructose
Sucrose = glucose + glucose
Maltose = glucose + glucose
The correct structures of the disaccharides are:
Maltose = glucose + glucose
Sucrose = glucose + fructose
Lactose = glucose + galactose