Download The Chemicals of Life

The Chemicals of Life
Carbon
“The element of Life”
Base element for many macromolecules in
the body
Carbon is a small element that can form 4
stable covalent bonds with other atoms
(look at valence electrons). The number of
covalent bonds an atom can form is called
its bonding capacity.
Carbon can bond to other carbon atoms in
straight chains, branched chains or rings.
Biological Macromolecules
Our body has four major macromolecules
that it uses.
Macromolecule – large molecules that are
sometimes composed of a great number of
repeating subunits.
There are four major classes:
- carbohydrates
- lipids
- proteins
- nucleic acids
Macromolecule
Subunit
complex
carbohydrate
(starch)
Lipid (triacylglycerol)
simple sugar (glucose)
protein
Nucleic acid (DNA
and RNA)
Glycerol and fatty
acids (not really
subunits)
Amino acids
nucleotides
Complicated carbohydrates, proteins
and nucleic acids are polymers,
meaning that they are long chains of
smaller subunits.
Condensation Reactions
Macromolecules are all made in the
same way, a condensation reaction
(dehydration synthesis reaction).
Creates covalent bonds between two
subunits.
It removes hydrogen from one subunit
and an OH- from the other subunit.
Condensation reactions are called
anabolic reactions because they
make one large molecule from
smaller subunits.
Hydrolysis Reactions
Sometimes cells break things apart.
Catabolic reactions break things
apart (digestion).
Hydrolysis reactions use a water
molecule to break apart a covalent
bond that holds subunits together.
The water molecule provides an H
atom to one subunit and an OH- group
to the other.
Hydrolysis and condensation reactions
require the use of enzymes (special
proteins).
Enzymes are catalysts, which speed up
chemical reactions and do not get
consumed in the chemical reaction.
Metabolism is the sum of all anabolic and
catabolic processes in a cell or organism.
* We will discuss metabolism and enzymes
later