1. Chapter 3

2.  Most of the molecules from which living
organisms are made are based on the
element carbon
 Carbon’s ability to form large and
complex molecules has contributed to
the great diversity of life

3.  Organic compounds – compounds
made primarily of carbon atoms
 Why is there such a variety of carbon
compounds?
• Four valence electrons
• Carbon readily bonds with other carbon atoms,
forming straight chains, branched chains, or
rings

5.  Single bond – one pair of electrons shared
 Double bond – two pairs of electrons shared
 Triple bond – three pairs of electrons shared

6.  Functional Groups – clusters of atoms in
organic compounds that influence the
characteristics of the molecules they
compose and the chemical reactions the
molecules undergo

8.  Monomers – small, simple molecules
 Polymers – molecules that consist of
repeated, linked units
 Large polymers are called
macromolecules

9.  Monomers link to form polymers through
a chemical reaction called a
condensation reaction
• Each time a monomer is added to a polymer, a
water molecule is released

10.  Living things also must break down
polymers
 In a hydrolysis reaction, water is used to
break down a polymer

11.  Life’s processes require a constant supply
of energy
 Energy is available in certain compounds
that store energy in their structure
• Common compound is ATP (adenosine
triphosphate)

12.  Covalent bonds between phosphate
groups are easy to break
 Every time a bond is broken, energy is
released
 The cell uses this energy to drive
chemical reactions that allow organisms
to function