Biochemistry is the study of organic chemistry,
mainly the compounds known as carbohydrates,
lipids, proteins, and nucleic acids.
All living things are made up of various chemical
compounds.
Atoms are the basic building blocks of matter
Elements are substances which are made of only
one kind of atom
Compounds are a combination of two or more
kinds of atoms in a defined proportion
Nucleus – made up of protons (+ charge, 1 atomic
mass unit) and neutrons (no charge, 1 atomic
mass unit)
# of protons = # of neutrons
Electrons – orbit the nucleus (- charge, very little
mass)

determine the chemistry of atoms

first energy level contains up to 2 electrons

outside levels can hold up to 8 electrons

when an electron orbital is full the atom is
chemically inactive

if orbital in not full the atom “looks” to
gain, lose, or share electrons with other
atoms
http://www.classzone.com/cz/books/bio_09/resource
s/htmls/animated_biology/unit1/bio_ch02_0059_ab_a
tombond.html (Great Review of atoms and bonding!)
Atomic number is equal to the number of protons
Mass number (atomic mass) is equal to the
number of protons plus the number of neutrons
Atom of an elements that has a different number
of neutrons from that of other atoms of the same
element
Radioactive isotopes are unstable and break down
at a constant rate over time (some can be used as
tracers)
Ionic bonds – Fig. 2-3 – form when atoms gain or
lose electrons, become chemically charged and
are attracted to each other
http://www.dnatube.com/video/366/Ionic-Bond
Covalent bonds – Fig. 2-4 – formed when atoms
share one or more pairs of electrons
http://www.dnatube.com/video/1290/Covalentbond
Van der Waals forces – Fig. 2-5 – a slight attraction
that develops between the oppositely charged
regions of nearby molecules
H2O – most important inorganic compound; All
organisms need H2O to survive. Formed by polar
covalent bonds between hydrogen & oxygen
inorganic – contains no carbon/hydrogen
bonds
organic – contains carbon
Polar Covalent Bonds are formed when partial
positive (+) and partial negative (-) charges are
formed as a result of unequal sharing of electrons
Polar Covalent Bonds are formed when partial
positive (+) and partial negative (-) charges are
formed as a result of unequal sharing of electrons
Hydrogen bonds are
weak electrical
attractions between
the partial negative
charge of one
molecule and the
partial positive charge
of a different
molecule
http://www.youtube.c
om/watch?v=lkl5cbfqF
RM
Cohesion is the attraction of molecules of the
same substance (Fig. 2-8). Because of cohesion of
H2O molecules, H2O is able to store a lot of heat.
This ability to store heat protects organisms from
damaging changes in temperature
Adhesion is the attraction
between molecules of one
substance and molecules of
another substance;
adhesion makes H2O one
of the best solvents
http://www.youtube.com/
watch?v=EBfGcTAJF4o&NR
=1
Solution – mixtures in which the molecules of the
substances are evenly distributed between the
solvent and the solute
Suspension – mixture of water and nondissolved
materials
Water (H2O) is a neutral molecule (neither acidic
or basic) which will dissociate into and equal
number of H+ and OH- and is the basis of pH
comparison
The pH scale (Fig.
2-10)
•pH of water is 7
•Acids have a greater [H+] than [OH-] pH is less than 7
•Bases have a greater [OH-] than [H+] pH is greater
than 7
•Buffers are weak acids or bases that can react with
strong acids or bases to help prevent sharp sudden
changes in pH (maintain homeostasis)
Carbon compounds contain carbon and usually
hydrogen; most occur naturally only in bodies &
products of living things
Electron Structure of Carbon
Carbon can bond with a variety of other
elements
Carbon can bond to other carbon molecules (Fig.
2-11)
Carbon can form single, double or triple bonds
Carbon can be bonded into long chains,
branches, or rings
Dehydration synthesis – a reaction in which 2
molecules are bonded together by the removal
of one H+ and one OH- to form H2O and another
compound
http://www.youtube.com/watch?v=b7TdWLNhM
tM&NR=1
Hydrolysis – a reaction in which a complex
molecule is broken apart into simpler molecules
by the addition of H2O
Function of Carbohydrates
Energy storage (Fig. 2-13)
starch is stored form of
sugar in plants
glycogen is stored form of
sugar in animals
Support
cellulose is found in plant
cell walls
chitin forms the
exoskeletons of
insects &arthropods
Structure of Lipids – Fats are made up of 1 glycerol
and three fatty acids (Fig. 2-14)
Structure of Lipids – Phospholipids are the major
component of cell membranes (Fig. 7-12)
Lipids also serve as:
insulation
energy storage
protection – organs; waxy cuticle on the surface
of leaves
Lipids are non-polar – will not dissolve in water
Structure of DNA – double helix – Fig. 12-7
Function of DNA – hereditary material, base pairs
act as a code that determines what proteins
will be made
Structure of RNA – Fig. 1212 – single chain of nucleic
acids that are involved in
protein synthesis
Structure
Fig. 2-17
Function
Structural – cartilage, bone, muscle
Hormones – chemical messengers (ex. – insulin)
Antibodies – prevent disease
Enzymes – speed up reactions
Transport proteins are found in cell membranes
Chemical reactions involve the breaking of bonds in
reactants and the formation of new bonds in products
Reactants – elements or compounds that enter
into a reaction
Products – elements or compounds that are
produced by a reaction
Energy in Reactions is either released or absorbed (Fig.
2-19)
Energy releasing reaction – the energy stored in the
reactants is greater than the energy stored in the
products (usually occurs spontaneously)
Energy absorbing reaction – the energy stored in the
products is greater than the energy stored in the
reactants (requires energy to initiate)
Activation energy – energy required to initiate a
reaction
http://www.classzone.com/cz/books/bio_09/
resources/htmls/animated_biology/unit1/bio
_ch02_0052_ab_exoendo.html
This link is a great review of difference
between exothermic and enothermic
reactions
Enzymes are protein catalysts that are necessary for
most of the chemical reactions that occur in living cells
Catalyst – substance that brings about a reaction
without being changed itself; can be re-used
Enzymes – lower the activation energy, energy needed to
break bonds, therefore reactions can occur quickly and
at normal body temps. (Fig. 2-20)
Enzyme Actions – Fig.
2-21
Substrate – substance
that enzyme acts upon
Enzymes are specific
for their substrates
Active site – the region
on the surface of an
enzyme where
substrate molecules
attach
http://highered.mcgra
whill.com/sites/00724958
55/student_view0/chap
ter2/animation__how_
enzymes_work.html
Regulation of Enzyme Activity
Only small amounts of enzymes are needed because
each molecule is re-used
Temperature – most enzymes work best at normal body
temperatures
pH – different enzymes work best at different ranges of
pH
Concentration of substrate & enzyme determines
reaction rate as long as both are freely accessible to
each other (up to a certain point)