Chapter 5

What role, if any, did polysaccharides play in chemical evolution?

Polysaccharides played little, if any, role in chemical evolution.

Cellulose is:

a major structural component of plant cell walls

A glycosidic linkage is analogous to which of the following in proteins?

peptide bond

Peptidoglycan forms sheets that stiffen the cell walls of bacteria. How is the formation of sheets possible?

Individual strands are joined by peptide bonds, a type of covalent bond.

Bacteria, insects, and plants use carbohydrates to build structures. Which of the following is true of structural carbohydrates?

Structural carbohydrates are long strands; the strands are chemically linked together to form a network.

Which of the following would you expect to have the most free energy per gram? The most free energy per gram would be found in a molecule with:

carbon and hydrogen atoms only

How do carbohydrates contain and/or display info for cells?

carbs contain and display info at the cell surface

What does the term insoluble fiber refer to on food packages?

cellulose

You isolate an organic molecule that contains C, H, O, N, and S. This molecule _____.

could be a glycoprotein

Chitin is a major component of the _____.

exoskeleton of insects

The molecule shown the accompanying figure is a _____. (6)

hexose

The molecular formula for glucose is C6H12O6. What would be the molecular formula for a molecule made by linking three glucose molecules together by dehydration reactions?

C18 H32 O16

The molecular formula for glucose is C6H12O6. What would be the molecular formula for a polymer made by linking ten glucose molecules together by dehydration reactions?

C60 H102 O51

Which of the following structural features is common to cellulose, chitin, and peptidoglycan?

They can all form bonds between polymer chains that create parallel strands.

Lactose, a sugar in milk, is composed of one glucose molecule joined by a glycosidic linkage to one galactose molecule. How is lactose classified?

as a disaccharide

Which of the following categories includes all others in the list?

carbohydrate

Cell walls are used by many different organisms for protection from their environment and structural support. These cell walls must obviously be insoluble in water; otherwise, they would dissolve the first time an organism got wet. Which of the following carbohydrates would you expect to be most soluble in water?

starch

The enzyme Amy lase can break glycosidic linkages between glucose monomers only if the monomers are the α form. Which of the following could amylase break down?

starch

What is the major structural difference between starch and glycogen?

the amount of branching that occurs in the molecule

What is the difference between an Aldose sugar and a ketose sugar?

the position of the carbonyl group