Chapter 13 Carbohydrates

Question 1

Carbohydrates can be classified based on the number of sugar units that compose the molecules. A polysaccharide has _______ units.

Answer 1

Greater than 10 sugar units

Question 2

Choose the best definition of enantiomers.

Answer 2

C) Two molecules with the same molecular formula and same connections. These two molecules are mirror images that are not superimposable

Question 3

Which sugar is not a reducing sugar?

Answer 3

Sucrose

Question 4

What color is observed in solution when a positive test using Benedict’s reagent occurs?

Answer 4

brick red

Question 5

Benedict’s test is used to identify the presence of what type of sugar?

Answer 5

reducing

Question 6

Which disaccharide naturally occurs in milk?

Answer 6

Lactose

Question 7

Which of the following is a disaccharide?

Answer 7

Lactose

Question 8

Identify the polysaccharide that is produced by plants and is used as a structural component of cell walls. Humans cannot digest this polysaccharide.

Answer 8

Cellulose is a polysaccharide produced by plants for the production of cell walls. These polysaccharides cannot be digested by humans and most other organisms.

Question 9

Plants store excess glucose as starch which is composed of amylose and amylopectin. Identify the characteristics of amylopectin.

Answer 9

Amylose and amylopectin are both polysaccharides composed of only glucose residues. Amylose is a straight chain polysaccharide with only α-1-4 linkages while amylopectin also contains branching due to α-1-6 linkages.

Question 10

Which of the following is a disaccharide?

Answer 10

Sucrose, also known as table sugar or cane sugar, is a disaccharide composed of one glucose bonded by a glycosidic bond to one fructose.

Question 11

Which of these polysaccharides contains β-glycosidic linkages?

Answer 11

Cellulose

Question 12

Identify the naturally occurring polysaccharide that is not easily digested by humans and is referred to as ‘dietary fiber’.

Answer 12

Cellulose