Unit 2 - Biochemistry
I. Chemical level
A.
Basic definitions
1.
2.
Matter –
Anything that has mass and
occupies space
Element - Basic unit of all
matter (109 +)
a.
92 naturally occurring elements
b.
Four basic elements for life – H,
C, O, N (96% of human mass)
Ca, P (additional 3%)
K, S, Cl, Mg, I, Fe, Na, along
with others (additional 1%)
c.
Atomic Structure
1.
Nucleus – protons (p+) and
neutrons (no)
2.
Electron cloud – outside of
nucleus
d.
Atomic # tells us the # of protons
e.
In a neutral atom, #p+ = #e-
f.
The atomic mass tells us the weighted
average of the element’s isotopes in atomic mass
units.
Isotopes – Atoms of the same element that have the
same number of p+ but a different # of no
For each isotope, the atomic mass is the
# of p+ + # of no
g.
Electrons in energy levels – 2, 8, 18, etc.
1.
Electrons may gain energy and jump to a
higher level
2.
If the outer levels (valence) of the
electron cloud fill, an atom is more stable
chemically
B. Bonding – Giving/receiving or sharing
of valence electrons through a chemical
reaction. Main types:
1.
Ionic –
One atom gains electrons, another
loses
This transfer of e- results in an atom that
carries a charge = ION
CATION - A positively charged ion that results
when a metal loses eANION - A negatively charged particle that
results when a nonmetal gains eElectrolytes – Ionic solutions
2.
Covalent – More common in the human body,
more stable
Result from sharing of 1-4 pairs of e-. EX:
3.
Hydrogen Bond - Weak bridges between molecules
that contain hydrogen covalently
bonded to O or N
a.
Only 5% as strong as a covalent bond
b.
Break and form easily
c.
Found in H2O, proteins, and nucleic acids
C.
Types of Reactions
1.
Synthesis reaction – Anabolic
AB
A + B 
(Reactants)
(Products)
http://www.dlt.ncssm.edu/core/Chapter5-Moles-MolarityReaction_Types/Chapter5-Animations/Synthesis.html
2.
Decomposition - Catabolic
AB
(Reactants)

A + B
(Products)
http://www.dlt.ncssm.edu/core/Chapter5-Moles-MolarityReaction_Types/Chapter5-Animations/Decomposition.html
3.
Exchange (Replacement) – Single or Double
AB + C 
AC + B
http://www.dlt.ncssm.edu/core/Chapter5-MolesMolarity-Reaction_Types/Chapter5Animations/SingleDisp_Reaction-MetalToAcid.html
AB + CD 
AD + CB
http://www.dlt.ncssm.edu/core/Chapter5-MolesMolarity-Reaction_Types/Chapter5Animations/DoubleDisp_Reaction-Precipitation.html
II. Chemical Compounds and Life Processes
A. Inorganic Compounds – Usually lack
carbon, relatively small
1.
H2O – Most abundant inorganic substance in a
human
a.
60% of red blood cells
b.
75% of muscle
c.
92% of plasma
d.
Solvent – liquid or gas that another
substance dissolves in, H2O is
the Universal Solvent
e.
Absorbs and releases heat slowly – helps in
maintaining homeostasis
f.
Lubricant – saliva, mucus
g.
Suspension medium
2.
Acids – dissociates into H+ and an anion
3.
HNO3  H+ + NO3Bases – dissociate into OH- and a cation
NaOH  Na+ +
4.
OH-
Salts – ionize to form anions and cations
NaCl  Na+ + Cl-
5.
pH – degree of acidity or alkalinity of a
solution
H+ = OH- neutral
H+ > acidic
OH- > basic
pH Scale
0-------------------------7-------------------------14
Many H+
H+ = OH-
Few OH-
Neutral
Acidic
Many OHFew H+
Basic
6.
Buffer System – Maintains the body’s pH
by replacing strong acids and bases with weak
acids and bases
D. Organic Compounds – Always contain
carbon, covalent
1.
Carbohydrates - Contain C, H, O
a.
Sugars – Based on the # of sugars
(saccharides), used for energy
storage, can be “burned” to
produce water, carbon dioxide and
energy.
* Monosaccharides (3-7 carbons), C:H:O=1:2:1
EX: Glucose, fructose, ribose, and
pentose (deoxyribose)
*Disaccharides – sucrose, galactose, maltose
Two simple sugars bond through a
dehydration synthesis (loss of water) =
GLYCOSIDIC LINKAGE
Glucose + Fructose = Sucrose
Glucose + Glucose = Maltose
Glucose + Galactose = Lactose
b.
Polysaccharides – made up of many glucoses in
a chain or branching chain. Starch (plants), glycogen
(animals)
Polysaccharides are
broken apart by
hydrolysis = addition
of water
2.
Lipids – C,H,O – no fixed ratio, most are not
water soluble (Hydrophobic)
a.
Triglycerides – two basic components are the
glycerol backbone and fatty acids
*harder to break down than carbs but provide 2X
the energy of carbs or proteins
*Saturated – single bonds between carbons, all C are
bonded to a maximum number of H ( beef, pork,
butter, whole milk, eggs, cheese) the liver produces
cholesterol form the breakdown of
*Monounsaturated – 1 double
covalent bond between
carbons (olive oil, peanut oil)
help reduce cholesterol
*Polyunsaturated – more
than 1 double bond (corn
oil, safflower, sunflower,
cottonseed, sesame,
soybean) help reduce
cholesterol
b.
Phospholipids – one saturated, one
unsaturated F.A., 3rd F.A. replaced with phosphate.
Amphipathic – one end of the molecule is
hydrophilic = (water loving)
The other end is hydrophobic =
(water fearing)
Phospholipids are important to structure of plasma
membrane
3.
Proteins – C,H,O,N
a.
Body structure, physiological activity (catalysts)
b.
Made up of building blocks known as amino
acids (20 different)
Each amino acid is made up of:
c.
Amino acids are connected by peptide bonds
producing dipeptides, tripeptides and polypeptides
http://student.ccbcmd.edu/~gkaiser/biotutorials/proteins/peptide.html
d.
Enzymes – normal body temperature and
pressure are both far too low for chemical reactions
to occur rapidly enough
*Regulators (catalysts)
*Enzymes are specific to a molecule =
Substrate http://www.lewport.wnyric.org/jwanamaker/animatio
ns/Enzyme%20activity.html
4.
Nucleic acids –
large organic
molecules made up
of C,H,O,P
a.
DNA – Double
helix – nitrogenous
bases, pentose
(deoxyribose) and
phosphate
b.
RNA – single strand, one nitrogenous base
is different from DNA, pentose is ribose
5.
ATP – Adenosine Triphosphate , short term
energy molecule = Adenine + Sugar + Phosphate