Chapter 8 - Carbohydrates Practice Quiz PDF

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This is the chapter 8 assignment for biochem I. Contains questions and answers. ...

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1/4 Biochemistry I Chapter 8: Carbohydrates Textbook: Fundamentals of Biochemistry: Life at the Molecular Level, 5th Edition. Donald Voet; Judith G. Voet Practice Quiz (WileyPLUS) 1. Match the following terms: 1. D-Erythrose 2. D-Fructose 3. D-Glyceraldehyde 4. D-Ribulose Aldotriose

3

Aldotetrose

1

Ketopentose

4

Ketohexose

2

2. Polysaccharides are polymers of saccharides 3. An epimer is an isomer that differs in configuration at one chiral center. 4. A sugar with a six-membered ring is known as a pyranose. 5. A sugar forms a cyclic-hemiacetal by reaction between an alcohol and an aldehyde. 6. An aldonic acid is the result of oxidation of the aldehyde group of an aldose. 7. True or false. Monosaccharides are aldehyde or ketone derivatives of straight-chain hydroxy alcohols that have at least 4 carbon atoms. False. NOTE: Monosaccharides have 3 or more carbon atoms.

2/4 8. True or false. D-sugars have the same absolute configuration at the asymmetric center farthest from their carbonyl group as does D-glyceraldehyde. True. 9. True or false. Aldoses of 5 or 6 carbons can form planar rings called pyranoses. False. NOTE: These rings are not planar, but take up the familiar chair or boat conformations. 10. Match the following: 1. Glycogen or amylopectin 2. Cellulose 3. Sucrose 4. Glycosaminoglycan 5. Lactose 6. Chitin 7. Amylose Nonreducing disaccharide

3

Reducing disaccharide

5

Polymer of D-glucose, β(1->4)

2

Polymer of N-acetyl-D-glucosamine, β(1->4)

6

Polymer of D-glucose,

7

(1->4)

Branched polymer of D-glucose α(1->4,1->6)

1

Linear polymer of uronic acid and hexosamine

4

11. Polysaccharides consist of monosaccharides linked by glycosidic bonds. 12. Polysaccharides form branched, as well as linear, polymers. 13. A sugar having an anomeric carbon that is not in a glycosidic bond is known as a reducing sugar.

3/4 14. Starch is a mixture of glycans that plants synthesize as their food reserve. 15. Match each of the following forms of business organization with a set of characteristics: 1. Cell-surface proteins that bind particular saccharides 2. Secreted or membrane-associated proteins which are covalently-linked to oligosaccharides 3. Aggregate of proteins and glycosaminoglycans in the extracellular matrix 4. Cell-surface saccharide-binding proteins that promote attachment of leukocytes to endothelial cells during infection or injury 5. Framework of polysaccharides and polypeptides that forms the bacterial cell wall Proteoglycan

3

Peptidoglycan

5

Glycosylated proteins

2

Lectins

1

Selectins

4

16. True or false. Exo- and endo-glycosidases are enzymes that hydrolyze chains of saccharides. True. 17. True or false. Glycogen, the storage polysaccharide of animals is present in all cells, but primarily in skeletal muscle and in liver. True. 18. True or false. Maltose is a disaccharide that appears when starches are broken down during digestion. True. 19. Alternating N-acetylglucosamine and N-acetylmuramic acid, in β-(1->4) linkages make up the polysaccharide component of peptidoglycan.

4/4 20. Asn or asparagines N-linked oligosaccharides are covalently attached to proteins through the side chain, N atom of 21. True or false. The carbohydrate content of glycoproteins varies (by weight) from 1% to >90%. True. 22. True or false. The oligosaccharides of most N-linked glycoproteins are very similar. False. NOTE: They are very diverse. 23. True or false. The flexible cell walls of bacteria are made from peptidoglycan, and permit them to live in hypotonic environments False. NOTE: They can live in hypotonic media because the peptidoglycan-based cell walls are rigid....