Monosaccharides

What are monosaccharides?

Monomers or single sugars that are the building blocks of carbohydrates.

What elements do all carbohydrates contain?

Carbon, hydrogen, and oxygen.

What is the general formula for monosaccharides?

(CH2O)n or Cn(H2O)n or CnH2nOn where n is the number of atoms.

What are structural isomers?

Molecules that have the same molecular formula but different arrangements of their atoms.

Can ribose and deoxyribose be structural isomers? Why or why not?

No, because they have different molecular formulae.

What is the difference between alpha (α) and beta (β) isomerism in sugars?

The position of the OH group on carbon atom 1; in alpha, the OH is below, and in beta, the OH is above.

What tip can help you remember the difference between alpha and beta forms of glucose?

ABBA: Alpha OH Below, Beta OH Above.

What distinguishes fructose from glucose and galactose?

Fructose has a central ring of four carbon atoms and one oxygen atom.

Which sugars can exist in both alpha and beta forms?

Glucose and galactose.

What group is at carbon atom 6 in fructose?

A CH2OH group.

In glucose and galactose, where is the CH2OH group located?

At carbon atom 6.

What is the position of OH on carbon atom 1 for Alpha and Beta Glucose and Alpha and Beta Galactose?

Alpha Glucose = Below

Beta Glucose = Above

Alpha Galactose = Below

Beta Galactose = Above

What is the position of OH on carbon atom 2 for Alpha and Beta Glucose and Alpha and Beta Galactose?

Alpha Glucose = Below

Beta Glucose = Below

Alpha Galactose = Above

Beta Galactose = Above

What is the position of OH on carbon atom 3 for Alpha and Beta Glucose and Alpha and Beta Galactose?

Alpha Glucose = Above

Beta Glucose = Above

Alpha Galactose = Below

Beta Galactose = Below

What is the position of OH on carbon atom 4 for Alpha and Beta Glucose and Alpha and Beta Galactose?

Alpha Glucose = Below

Beta Glucose = Below

Alpha Galactose = Below

Beta Galactose = Below