UNIT 1: Biochemistry
1.3: The Carbon Chemistry of Life
pg. 25 – 28
Carbon Chains – The Backbone of Biochemistry
Hydrocarbons - are molecules that are made up of a carbon and hydrogen
atoms, such as: methane.
Organic molecules - are molecules consisting of a carbon chain, with
hydrogen and other atoms (nitrogen, oxygen, and sulfur) attached.
Carbon has the ability to form the back-bone of large diverse molecules,
because of the carbon’s ability to form bonds (four covalent bonds). These
carbon chains (carbon skeletons) can form linear, ringed, and multi –
branched molecules.
Carbon has the ability to form four single covalent bonds, but may also form
double and triple covalent bonds.
Carbon molecules can form polymers, complex molecules made up of many
repeating monomers, such as; carbohydrates, proteins, and nucleic acids.
The lipid molecule is a not a polymer, made up many repeating monomers,
but is composed of subunits glycerol and fatty acid chains.
Functional Groups
Functional group - is a group of atoms that affects the function of a
molecule by participating in chemical reactions.
Functional groups are usually strongly polar or ionic. They form small
reactive groups which allow organic molecules to undergo synthesis and
degradation reactions.
Characteristics of Functional Groups
Large biological macromolecules are influenced by the polar and ionic
characteristics of its functional groups, both physically and chemically.
These functional groups allow chemical reactions to occur, break and form
new bonds.
Hydroxyl
Carbonyl
(OH)
(=O) end
(=O) mid
Carboxyl (COOH)
Amino
(NH2)
Phosphate (PO4)
Sulfhydryl (SH)
alcohol
ethyl Alcohol
aldehyde
acetaldehyde
ketone
acetone
organic acids
acetic acid
amino acids
alanine
nucleic acids
glyceraldehydes-3-phosphate
cellular molecules
mercaptoethanol
Dehydration and Hydrolysis Reactions
In these reactions H+ and OH- ions are gained or lost from organic
molecules.
Dehydration reaction requires the removal of water, usually during the
building of a larger molecule from smaller subunits. (Anabolic reaction)
(Bonding of two glucose molecules to form maltose)
Hydrolysis reaction requires the addition of water, usually during the
breaking down of larger molecules into smaller subunits. (Catabolic reaction)
(Maltose is broken down into two molecules of glucose)
Hydrolysis and dehydration reactions are among the most important
reactions in cells.