Question 1

Based on the form of the cyclic sugar shown below in a Haworth projection, which Fischer projection formula could have formed this structure?

Accepted Answer

A)   
B)   
C)   
D)   
E)   
A)   
B)   
C)   
D)   
E)

Question 2

Which pair is epimeric?

Accepted Answer

A)  D-glucose and D-glucosamine 
B)  D-glucose and D-mannose 
C)  D-glucose and L-glucose 
D)  D-lactose and D-sucrose 
E)  L-mannose and L-fructose 
A)  D-glucose and D-glucosamine 
B)  D-glucose and D-mannose 
C)  D-glucose and L-glucose 
D)  D-lactose and D-sucrose 
E)  L-mannose and L-fructose

Question 3

(a) How many asymmetric carbons (chiral centers) does each of the anomers of glucose in the pyranose ring form structure have? (b) How many stereoisomers of the glucose are theoretically possible?

Accepted Answer

(a) In the pyranose ring form of glucose

Question 4

Describe the process by which "old" serum glycoproteins are removed from the mammalian circulatory system.

Accepted Answer

The removal of "old" serum glycoproteins

Question 5

Describe the structure of a proteoglycan aggregate such as is found in the extracellular matrix.

Accepted Answer

Proteoglycan aggregates are large macrom

Question 6

Match these molecules with their biological roles.
(a) glycogen
__ viscosity, lubrication of extracellular secretions
(b) starch
__ carbohydrate storage in plants
(c) trehalose
__ transport/storage in insects
(d) chitin
__ exoskeleton of insects
(e) cellulose
__ structural component of bacterial cell wall
(f) peptidoglycan
__ structural component of plant cell walls
(g) hyaluronate
__ extracellular matrix of animal tissues
(h) proteoglycan
__ carbohydrate storage in animal liver

Accepted Answer

The molecules listed are important biolo

Question 7

When forming the disaccharide maltose from two glucose monosaccharides:

Accepted Answer

A)  water is eliminated. 
B)  a hemiacetal is converted to an acetal. 
C)  the resulting dissacharide is no longer a reducing sugar. 
D)  water is eliminated and a hemiacetal is converted to an acetal. 
E)  None of the answers is correct. 
A)  water is eliminated. 
B)  a hemiacetal is converted to an acetal. 
C)  the resulting dissacharide is no longer a reducing sugar. 
D)  water is eliminated and a hemiacetal is converted to an acetal. 
E)  None of the answers is correct.

Question 8

During which process are chemical bonds NOT broken?

Accepted Answer

A)  mutarotation 
B)  interconverting between two configurations 
C)  interconverting between two conformations 
D)  interconverting between two anomers 
E)  None of the answers is correct: all involve breaking a chemical bond. 
A)  mutarotation 
B)  interconverting between two configurations 
C)  interconverting between two conformations 
D)  interconverting between two anomers 
E)  None of the answers is correct: all involve breaking a chemical bond.

Question 9

Which arrow CORRECTLY identifies the atom that will become the anomeric carbon?

Accepted Answer

A)  A 
B)  B 
C)  C 
D)  D 
E)  E 
A)  A 
B)  B 
C)  C 
D)  D 
E)  E

Question 10

About what percentage of mammalian proteins are glycosylated?

Accepted Answer

A)  5% 
B)  15% 
C)  50% 
D)  90% 
E)  95% 
A)  5% 
B)  15% 
C)  50% 
D)  90% 
E)  95%

Question 11

Identify all the epimeric pairs in the structures shown below.

Accepted Answer

The answer of Identify all the epimeric pairs in the...

Question 12

Explain in molecular terms why humans cannot use cellulose as a nutrient, but goats and cattle can.

Accepted Answer

Humans cannot use cellulose as a nutrien

Question 13

The polysaccharide chitin is MOST chemically similar to:

Accepted Answer

A)  cellulose. 
B)  dextran. 
C)  glycogen. 
D)  starch. 
E)  amylose. 
A)  cellulose. 
B)  dextran. 
C)  glycogen. 
D)  starch. 
E)  amylose.

Question 14

Which pair is interconverted in the process of mutarotation?

Accepted Answer

A)  D-glucose and D-fructose 
B)  D-glucose and D-galactose 
C)  D-glucose and D-glucosamine 
D)  D-glucose and L-glucose 
E)  $\alpha$-D-glucose and $\beta$-D-glucose 
A)  D-glucose and D-fructose 
B)  D-glucose and D-galactose 
C)  D-glucose and D-glucosamine 
D)  D-glucose and L-glucose 
E)  $\alpha$-D-glucose and $\beta$-D-glucose

Question 15

_____ is the determination of the full component and function of sugar-containing molecules in a cell or tissue.

Accepted Answer

A)  Genomics 
B)  Proteomics 
C)  Glycomics 
D)  Metabolomics 
E)  Lipidomics 
A)  Genomics 
B)  Proteomics 
C)  Glycomics 
D)  Metabolomics 
E)  Lipidomics

Question 16

Define "reducing sugar." (b) Show the reaction product of glucose after it is used as a reducing sugar. (c) Explain why fructose is also considered a reducing sugar. (Hint: It must first undergo a chemical conversion.) (d) Sucrose is a disaccharide composed of glucose and fructose (Glc($\alpha$1 $\rightarrow$ 2)Fru). Explain why sucrose is not a reducing sugar, even though both glucose and fructose are.

Accepted Answer

(a) A reducing sugar is a carbohydrate t

Question 17

The glycosaminoglycans are negatively charged at neutral pH. What components of these polymers confer the negative charge?

Accepted Answer

Glycosaminoglycans (GAGs) are long, unbr

Question 18

Which modification CANNOT be made to a sugar molecule by an organism?

Accepted Answer

A)  oxidation of the carbonyl carbon 
B)  replacing a hydroxyl group with an amino group 
C)  oxidizing a carbon atom to a carboxyl group 
D)  replacing a hydroxyl group with a hydrogen atom. 
E)  All of the answer choices are possible sugar derivatives. 
A)  oxidation of the carbonyl carbon 
B)  replacing a hydroxyl group with an amino group 
C)  oxidizing a carbon atom to a carboxyl group 
D)  replacing a hydroxyl group with a hydrogen atom. 
E)  All of the answer choices are possible sugar derivatives.

Question 19

Briefly explain how the drugs Tamiflu and Relenza work to prevent the flu.

Accepted Answer

Tamiflu (oseltamivir) and Relenza (zanam

Question 20

In measuring long-term glucose levels in the bloodstream, glycated hemoglobin must be separated from unmodified hemoglobin to determine the percentage of glycated hemoglobin. Suggest a simple chromatographic method by which this separation can be performed.

Accepted Answer

One simple chromatographic method that c

Exam 7: Carbohydrates and Glycobiology

Based on the form of the cyclic sugar shown below in a Haworth projection, which Fischer projection formula could have formed this structure?

Which pair is epimeric?

(a) How many asymmetric carbons (chiral centers) does each of the anomers of glucose in the pyranose ring form structure have? (b) How many stereoisomers of the glucose are theoretically possible?

Describe the process by which "old" serum glycoproteins are removed from the mammalian circulatory system.

Describe the structure of a proteoglycan aggregate such as is found in the extracellular matrix.

When forming the disaccharide maltose from two glucose monosaccharides:

During which process are chemical bonds NOT broken?

Which arrow CORRECTLY identifies the atom that will become the anomeric carbon?

About what percentage of mammalian proteins are glycosylated?

Identify all the epimeric pairs in the structures shown below.

Explain in molecular terms why humans cannot use cellulose as a nutrient, but goats and cattle can.

The polysaccharide chitin is MOST chemically similar to:

Which pair is interconverted in the process of mutarotation?

_____ is the determination of the full component and function of sugar-containing molecules in a cell or tissue.

The glycosaminoglycans are negatively charged at neutral pH. What components of these polymers confer the negative charge?

Which modification CANNOT be made to a sugar molecule by an organism?

Briefly explain how the drugs Tamiflu and Relenza work to prevent the flu.

In measuring long-term glucose levels in the bloodstream, glycated hemoglobin must be separated from unmodified hemoglobin to determine the percentage of glycated hemoglobin. Suggest a simple chromatographic method by which this separation can be performed.

The Foundations of Biochemistry

Water

Amino Acids, Peptides, and Proteins

The Three-Dimensional Structure of Proteins

Protein Function

Enzymes

Nucleotides and Nucleic Acids

DNA-Based Information Technologies

Lipids

Biological Membranes and Transport

Biosignaling

Bioenergetics and Biochemical Reaction Types

Glycolysis, Gluconeogenesis, and the Pentose Phosphate Pathway

Principles of Metabolic Regulation

The Citric Acid Cycle

Fatty Acid Catabolism

Amino Acid Oxidation and the Production of Urea

Oxidative Phosphorylation and Photophosphorylation

Carbohydrate Biosynthesis in Plants and Bacteria

Lipid Biosynthesis

Biosynthesis of Amino Acids, Nucleotides, and Related Molecules

Hormonal Regulation and Integration of Mammalian Metabolism

Genes and Chromosomes

DNA Metabolism

RNA Metabolism

Protein Metabolism

Regulation of Gene Expression

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