Module 7 - 3

Question 1

What are disaccharides?

Answer 1

Two monosaccharides joined by a glycosidic bond.

Question 2

What is nomenclature?

Answer 2

Naming system for disaccharides.

Question 3

What are the steps involved in nomenclature?

Answer 3

1. Specify configuration at anomeric carbon. 2. Specify ring form. 3. Non-reducing sugar suffix is ‘osyl’. 4. Reducing sugar suffix is ‘ose’. 5. Indicate glycosidic bond with an arrow.

Question 4

What is maltose?

Answer 4

Disaccharide composed of two glucose molecules.

Question 5

What is lactose?

Answer 5

Disaccharide composed of glucose and galactose.

Question 6

What happens to lactose intolerant individuals when they consume lactose?

Answer 6

They experience bloating, cramps, flatulence, diarrhea and nausea due to insufficient lactase enzyme.

Question 7

What is lactase?

Answer 7

Enzyme that catalyzes the hydrolysis of lactose into glucose and galactose.

Question 8

What is lactase persistence?

Answer 8

Ability to produce lactase after weaning.

Question 9

What are polysaccharides?

Answer 9

Polymers of monosaccharides with diverse structures and functions.

Question 10

What are the biological functions of polysaccharides?

Answer 10

Energy storage, structural roles, cushioning and lubrication, etc.

Question 11

What are homopolysaccharides?

Answer 11

Polymers containing a single type of monosaccharide.

Question 12

What are heteropolysaccharides?

Answer 12

Polymers containing more than one type of monosaccharide.

Question 13

What are the types of homopolysaccharides?

Answer 13

Unbranched or branched.

Question 14

What are the types of heteropolysaccharides?

Answer 14

Unbranched or branched.

Question 15

What are energy storage polysaccharides?

Answer 15

Polysaccharides that store glucose intracellularly.

Question 16

What are the two types of energy storage polysaccharides?

Answer 16

Starch and glycogen.

Question 17

What is starch?

Answer 17

Mixture of amylose and amylopectin found in plants and fungi.

Question 18

What is glycogen?

Answer 18

Polymer of glucose stored in liver and skeletal muscle of animals.

Question 19

What is amylose?

Answer 19

Linear polymer of glucose residues through α(1-4) bonds.

Question 20

What is amylopectin?

Answer 20

Polymer of α(1-4) linked glucose residues with α(1-6) branch points every 24-30 residues.

Question 21

What are the enzymes involved in starch breakdown?

Answer 21

Amylase and debranching enzyme.

Question 22

What is the difference between amylose and amylopectin?

Answer 22

Amylose has a single non-reducing end, while amylopectin has multiple non-reducing ends.

Question 23

What is glycogen?

Answer 23

A polysaccharide present in all cells, but most prevalent in skeletal muscle and liver.

Question 24

What is the structure of glycogen?

Answer 24

Structurally identical to amylopectin, consisting of α(1-4) linked glucose residues with α(1-6) branch points but with a higher frequency of branch points (every 10 residues).

Question 25

How is glycogen mobilized?

Answer 25

Glycogen phosphorylase sequentially cleaves glucose residues from non-reducing ends.

Question 26

What is the advantage of the greater frequency of branching in glycogen?

Answer 26

It allows for rapid mobilization.

Question 27

What is cellulose?

Answer 27

The primary component of plant cell walls (fiber), a linear, homopolysaccharide of glucose residues.

Question 28

What is the arrangement of glycosidic residues in cellulose?

Answer 28

A linear arrangement of β(1-4) glycosidic residues.

Question 29

Why can’t amylase cut the bonds in cellulose?

Answer 29

Because of the β(1-4) glycosidic residues arrangement.

Question 30

What is chitin?

Answer 30

The principal component of hard exoskeletons (insects, lobsters, etc), a linear, homopolysaccharide of N-acetylglucosamine residues.

Question 31

What is chitin?

Answer 31

The replacement of hydroxyl group at C2 with acetylated amino group.

Question 32

What is the advantage of the β1-4 linkages in cellulose and chitin?

Answer 32

They allow formation of long straight chains.

Question 33

How are fibrils formed in cellulose and chitin?

Answer 33

Parallel chains are linked through hydrogen bonds.

Question 34

What is the advantage of the fibers generated by cellulose and chitin?

Answer 34

They generate a rigid supportive structure of high tensile strength.

Question 35

What is the structure of starch and glycogen?

Answer 35

The α1-4 linkages form a hollow, helical structure.

Question 36

What is the advantage of the hollow helix structure in starch and glycogen?

Answer 36

It provides a compact, accessible storage structure of glucose.

Question 37

What are glycolipids?

Answer 37

Sugars covalently linked to lipid molecules.

Question 38

What is the central function of glycolipids?

Answer 38

In the blood group antigens.

Question 39

What is the difference between amylose and amylopectin reducing ends?

Answer 39

Amylose and amylopectin each have a single reducing end.

Question 40

What are glycoproteins?

Answer 40

Proteins with covalently attached sugars.

Question 41

What is the largest component by weight in glycoproteins?

Answer 41

The protein constituent.

Question 42

What is the function of glycoproteins?

Answer 42

Serve a variety of biological roles.

Question 43

What are proteoglycans?

Answer 43

Protein component linked to glycosaminoglycan.

Question 44

What is the largest component by weight in proteoglycans?

Answer 44

The carbohydrate constituent.

Question 45

What is the function of proteoglycans?

Answer 45

Often serve structural and lubricating functions.

Question 46

What are blood group antigens?

Answer 46

Differences critical for blood transfusions.

Question 47

What is Type O blood?

Answer 47

Universal donor, can be given to all blood types.