Biochem Chapter 7

How many stereoisomers does D-ribose, an aldopentose, have?

8 (3 chiral centers so 2^3)

Define heteropolysaccharide

A polysaccharide containing two or more different monosaccharide units

Preoteoglycans are made of core protein(s) attached to _____________ A) Glycosaminoglycans B) diverse and several monosaccharides (other than glycosaminoglycans) C) only glucose D) Both A and B

A) Glycosaminoglycans

The monomer of chitin is: A) N-acetyl glucosamine B) N-acetyl galactosamine C) glucose D) both A and C

A) N-acetyl glucosamine

Heparin is a highly negatively charged glycosaminoglycan that act as an ________. A) anticoagulant B) structure of cell wall C) storage carbohydrate D) structural carbohydrate

A) anticoagulant

In glycoproteins, the carbohydrate moiety is always attached through the amino acid residues: A) asparagine, serine, or threonine. B) tryptophan, aspartate, or cysteine. C) glycine, alanine, or aspartate. D) aspartate or glutamate.

A) asparagine, serine, or threonine.

All of the following are homopolysaccharides EXCEPT for: A) hyaluronan B) Chitin C) Starch D) Cellulose

A) hyaluronan

The glycosidic linkage in cellulose is ____________, which is acted upon enzyme called cellulase. A) β(1-4) B) α(1-4) C) β (1-6) D) α(1-6)

A) β(1-4)

Under what conditions do glycocidic bonds hydrolyze?

Acidic conditions

What statement is FALSE for lactose, its abbreviated name is Gal(β1→4)Glc. A) C-1 of Galactose(Gal) is attached to C-4 of glucose (Glc) via glycosidic bond B) Anomeric carbon of Glucose (Glu) is bond to anomeric carbon of Galactose(Gal) via glycosidic bond C) The anomeric carbon of Galactose is in β form D) Anomeric carbon of Galactose (Gal) is bond to non-anomeric carbon of Glucose(Glc) via glycosidic bond

B) Anomeric carbon of Glucose (Glu) is bond to anomeric carbon of Galactose(Gal) via glycosidic bond

Glucose and mannose are examples of: A) Enantiomers B) Epimers C) Anomers D) Aldose/Ketose

B) Epimers

Which of the following is a dominant feature of the outer membrane of the cell wall of gram negative bacteria? A) Glycogen B) Glycolipids (Lipopolysaccharides) C) Glycoproteins D) Proteoglycans

B) Glycolipids (Lipopolysaccharides)

What is the benefit of branching in storage polysaccharides? A) It allows tighter packaging of the polysaccharide. B) It creates more ends for rapid glucose access during energy needs C) It forces the glycosidic linkages to be all α-conformation. D) None of these are actual benefits.

B) It creates more ends for rapid glucose access during energy needs

Consider the configuration of most hexoses and amino acids found in living organisms. Which of the following statements is correct? A) Most hexoses and amino acids are found as L-isomers in living organisms. B) Most hexoses are found as D-isomers in living organisms, whereas most amino acids are found as L-isomers in living organisms. C) Most hexoses and amino acids are found as D-isomers in living organisms. D) Most hexoses are found as L-isomers in living organisms, whereas most amino acids are found as D-isomers in living organisms.

B) Most hexoses are found as D-isomers in living organisms, whereas most amino acids are found as L-isomers in living organisms.

Which of following is an anomeric pair? A) d-glucose and d-fructose B) a-d-glucose and b-d-glucose C) d-glucose and d-mannose D) d-glucose and l-glucose

B) a-d-glucose and b-d-glucose

When two carbohydrates are epimers: A) they rotate plane-polarized light in the same direction. B) they differ only in the configuration around one carbon atom. C) they differ in length by one carbon. D) one is a pyranose, the other a furanose. E) one is an aldose, the other a ketose.

B) they differ only in the configuration around one carbon atom.

Homopolysaccharides

Chitin Starch Cellulose Glycogen

Which of the following statements is true regarding glycogen and starch? A) Both are polymers of subunits of glucose(α1→4)-linked, with (α1→6)-linked branches. B) Both are branched homopolysaccharides C) Glycogen is a form of energy storage in plants, whereas starch is an energy storage form in animals. D) A and B

D) A and B

Due to the negatively charged nature of glycosaminoglycans, they A) have extended structure B) are highly hydrated and function in lubrication of joints C) negative charge is due to carboxyl (COO-) or sulfate functional groups on sugar. D) All the above

D) All of the above

What statement below is FALSE regarding glycosaminoglycans? A) They long unbranched heteropolysaccharides consisting of a repeating disaccharide unit B) One saccharide unit is N-acetylglucosamine or N-acetylgalactosamine in glycosamineglycans. C) Another unit is negatively charged saccharide in glycosamineglycans. D) An example of glycosamineglycan include chitin

D) An example of glycosamineglycan include chitin

What is the only nonchiral carbohydrate?

Dihydroxyacetone

What is the benefit of branching in storage polysaccharides?

It creates more ends for rapid glucose access during energy needs