Carbohydrate (Chapter 18) Practice Problems

Question 1:

Show galactose in cyclic acetal forms having 3-, 4-, 5-, and 6-membered rings. Indicate which forms are present at equilibrium in significant quantities and why.
Sugar Structures

Question 2:

One cyclic acetal form of D-Galactose is shown below.

Part A

Which atom is the anomeric carbon?

Atom A Atom B Atom C Atom D Atom E Atom F

Part B

Which name most completely describes this cyclic acetal form?

a-D-Galactofuranose b-D-Galactofuranose a-D-Galactopyranose b-D-Galactopyranose



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Question 3:

The parts of question 3 refer to the set of molecules in the following figure.

Part A

Which molecule(s) is(are) a methyl glycopyranoside?

Molecule A Molecule B Molecule C Molecule D Molecule E Molecule F

Part B

Which molecule(s) is(are) a b-1,4-linked disaccharide?

Molecule A Molecule B Molecule C Molecule D Molecule E Molecule F

Part C

Which molecule(s) is(are) an a-1,4-linked disaccharide?

Molecule A Molecule B Molecule C Molecule D Molecule E Molecule F

Part D

Which molecule(s) is(are) an N-linked glycoside?

Molecule A Molecule B Molecule C Molecule D Molecule E Molecule F


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Question 4:

A solution of D-arabinose contains 60% a-D-arabinopyranose, 35.5% b-D-arabinopyranose, and minor amounts of other forms. Draw the most stable conformational representation of both of these pyranose forms and explain why a-D-arabinopyranose is the major form in solution at equilibrium.

Sugar Structures

Question 5:

Which of the molecules below will react with Ag+?

Molecule A Molecule B Molecule C Molecule D Molecule E Molecule F


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Last modified 4/21/97

Abby Parrill
Department of Chemistry
Michigan State University

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