Biology 12

Chapter 1 The Chemistry of Life • MHR 17

Monomers and Macromolecules

As you know, atoms can join together — bond — to
form small compounds called molecules. Similarly,
molecules can join together to form large structures
called macromolecules. The small, molecular
subunits that make up macromolecules are called
monomers. The macromolecules themselves are
built up of long chains of monomers. These chains
are called polymers.
Table 1.2 lists the main types of macromolecules
and their monomer subunits. Figure 1.14 depicts
the subunits that comprise carbohydrates, selected
lipids, proteins, and nucleic acids. Chemical
reactions in cells synthesize macromolecules from
these subunits, and break the molecules apart to
release their subunits. Refer to Figure 1.14 often as
you examine these chemical reactions in the final
section of this chapter.

Lipids

fats

phospholipids

steroids

terpenes

Nucleic acids

DNA

RNA

glycerol + three fatty

acids

glycerol + two fatty

acids + phosphate

four carbon rings

long carbon chains

nucleotides

nucleotides

energy storage

component of cell

membranes

message transmission

(hormones)

pigments in photosynthesis

encoding of heredity

information

blueprint of heredity

information

Macromolecule Sub-unit Function

Carbohydrates

glucose

(monosaccharide)

starch, glycogen

(polysaccharides)

cellulose

(polysaccharide)

chitin

(polysaccharide)

Proteins

globular

structural

–

glucose

glucose

modified glucose

amino acids

amino acids

energy storage

energy storage

component of plant cell

walls

cell walls of fungi; outer

skeleton of insects and

related groups

catalysis

support and structure

Table 1.

Macromolecules and their subunits and functions

http://www.mcgrawhill.ca/links/biology
To learn how researchers use molecular models to help them
investigate the structure of complex molecules, go to the web
site above, and click on Web Links. Identify a scientific
discovery in which molecular modelling played a significant
role. What techniques or technologies were used in the
construction of the model? Present your findings in a class
workshop on methods of molecular modelling.

WEB LINK

+

H C OH

H

H C OH

H C OH C

H H

H

C

H

C

H

C

H

H

C C

H

H

H

C

H

H H H

C

H

C

H

C

H

H

C

HO

HO

HO

C

H

H

C

H

H

H

C

H

H H H

C

H

C

H

C

H

H

C

O

O

O

H

glycerol

3 fatty acids

H

O O

O

O

PO O−

C

H

H

C

OH

H

C

sugar

(deoxyribose)

nitrogen base

phosphate

group

CH 2

C

OH

OH

C

H

H

C

OH

H

C

HO

H

CO

H

CH 2 OH

glucose

A glucose molecule, the

subunit for carbohydrates

Glycerol and three fatty acid molecules,

the subunits for fats (triglycerides)

A nucleotide

molecule, the

subunit for

nucleic acids

Figure 1.14A Notice the prevalence of carbon, hydrogen, and oxygen atoms
in the monomers that comprise the macromolecules of life.