The Structure and Function of Large Biological Molecules

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Slide 1

The Molecules of Life

All living things are made up of four classes of large biological molecules: carbohydrates, lipids, proteins, and nucleic acids

Within cells, small organic molecules are joined together to form larger molecules

Macromolecules are large molecules composed of thousands of covalently connected atoms

Molecular structure and function are inseparable

Slide 2

Fig. 5-1

Slide 3

Concept 5.1: Macromolecules are polymers, built from monomers

A polymer is a long molecule consisting of many similar building blocks

These small building-block molecules are called monomers

Three of the four classes of life’s organic molecules are polymers:

Carbohydrates

Proteins

Nucleic acids

Slide 4

The Synthesis and Breakdown of Polymers

A condensation reaction or more specifically a dehydration reaction occurs when two monomers bond together through the loss of a water molecule

Enzymes are macromolecules that speed up the dehydration process

Polymers are disassembled to monomers by hydrolysis, a reaction that is essentially the reverse of the dehydration reaction

Animation: Polymers

Slide 5

Fig. 5-2

Short polymer

HO

1

2

3

H

HO

H

Unlinked monomer

Dehydration removes a water

molecule, forming a new bond

HO

H2O

H

1

2

3

4

Longer polymer

(a) Dehydration reaction in the synthesis of a polymer

HO

1

2

3

4

H

H2O

Hydrolysis adds a water

molecule, breaking a bond

HO

H

H

HO

1

2

3

(b) Hydrolysis of a polymer

Slide 6

Fig. 5-2a

Dehydration removes a water

molecule, forming a new bond

Short polymer

Unlinked monomer

Longer polymer

Dehydration reaction in the synthesis of a polymer

HO

HO

HO

H2O

H

H

H

4

3

2

1

1

2

3

(a)

Slide 7

Fig. 5-2b

Hydrolysis adds a water

molecule, breaking a bond

Hydrolysis of a polymer

HO

HO

HO

H2O

H

H

H

3

2

1

1

2

3

4

(b)

Slide 8

The Diversity of Polymers

Each cell has thousands of different kinds of macromolecules