Chapter 7: Monosacharides, Polysacharides and Glucose Storage

Question 1

What is the 2-epimer of glucose?

Answer 1

Mannose

Question 2

What is the 4-epimer of glucose?

Answer 2

Galactose

Question 3

What is the difference between a pyran ring and a furan ring?

Answer 3

The pyran is a six member ring (including the oxygen) and a furan is a five member ring (including the oxygen).

Question 4

Are sugars normally linear or cyclized?

Answer 4

Most of the time they are cyclized (99%)

Question 5

What is the anomeric carbon?

Answer 5

The carbon that has the hemi-acetal. It can be either alpha or beta.

Question 6

What does alpha-d-glucose look like in a Haworth projection?

Answer 6

Question 7

What does alpha-d-mannose look like in a Haworth projection?

Answer 7

Question 8

What does alpha-d-galactose look like in a Haworth projection?

Answer 8

Question 9

What does alpha-d-ribose look like in a Haworth projection?

Answer 9

Question 10

What does alpha-d-fructose look like in a Haworth projection?

Answer 10

Question 11

What does beta-d-glucose look like in a Haworth projection?

Answer 11

Question 12

What does beta-d-mannose look like in a Haworth projection?

Answer 12

Question 13

What does beta-d-galactose look like in a Haworth projection?

Answer 13

Question 14

What does beta-d-ribose look like in a Haworth projection?

Answer 14

Question 15

What does beta-d-fructose look like in a Haworth projection?

Answer 15

Question 16

Know about epimers, anomers, (1)

Answer 16

Epimers are stereoisomerse that differ at only one chiral center. Multiple chiral C= multiple possible epimers. Anomers are stereoisomers at the anomeric C, formed when sugars cyclize (alpha and beta anomers).

Question 17

Know how to name disaccharides or draw named dissacharides (1)

Answer 17

1.) Give the configuration (alpha or beta) at the anomeric carbon joining the first monosaccharide unit (on the left) to the second. 2.) Name the nonreducing residue; to distinguish five-and six-membered ring structures, insert furano or pyrano into the name. 4.) Name the second residue. If they are two non-reducing sugars, the second residue ends in -side not -ose.

Question 18

Name the two most important storage polysaccharides and where they are found.

Answer 18

A tightly coiled chain of glucose called Starch (found in plant cells) and Glycogen (found in animal cells).

Question 19

What is starch?

Answer 19

An important storage polysaccharide found in plant cells that contains two types of glucose polymer, amylose and amylopectin.

Question 20

What does amylose consist of?

Answer 20

Amylose consists of long, unbranched chains of D-glucose residues connected by (alpha1-4) linkages.

Question 21

What makes amylopectin different from amylose?

Answer 21

Unlike amylose, amylopectin is highly branched. They have the alpha 1-4 glycosidic linkages, but every 24 to 30 residues are branch points with alpha 1-6 linkages.

Question 22

What is glycogen?

Answer 22

Glycogen is the main storage polysaccharide of animal cells. Like amylopectin, glycogen is a polymer of (alpha 1-4)-linked subunits of glucose, with (alpha 1-6)-linked branches. Glycogen is more extensively branched (about every 10 residues) and more compact than starch.

Question 23

What is amylase breakdown?

Answer 23

Alpha-amylase is an endoglycosidase that cleaves internal alpha 1-4 glycosidic linkages.

Question 24

Know about the structural features of cellulose and differences vs amylose, amylopectin, glycogen (2)

Answer 24

It is an unbranched glucose polymer with beta 1-4 linkage. This beta linkage causes it to fold differently in space than amylose, which has an alpha 1-4 linkage. Each glucose molecule is turned 180 degrees relative to its neighbor, which forms long straight chains. H-bonding between the oxygen in the ring and the 3-OH helps stabilize it. Parallel adjacent chains form fibrils through H-bonding.

Question 25

What are glucosaminoglycans and where do they occur?

Answer 25

They are multifunctional heteropolysaccharides of the extracellular matrix. They are repeating disaccharides with alternating uronic acid and amino sugars. Fills extracellular space (ground substance) along with fibrous proteins (elastin, collagen, fibronectin, laminin). The negative charges repulse, causing it to fan out like a bottle brush.

Question 26

What is chondroitin sulfate?

Answer 26

It is a glycosaminoglycan that strengthens cartilage, tendons, ligaments, and walls of blood vessels.

Question 27

What is hyaluronan (hyaluronic acid)?

Answer 27

It is a glycosaminoglycan that forms the lubricant in joints, vitreous of eye, part of cartilage and tendons.