Transcript Chap. 3 : Biochemistry - Fort Thomas Independent Schools

A. Water (H2O)
- Polar – compound with one side having
a (-) charge and the other a (+) charge.
OH+
H+
-- hydrophilic – “water-loving” substances that
are attracted to water (polar things)
-- hydrophobic – “water-fearing” substances
that do not like water (nonpolar things).
ex. Fats, oils, waxes
* Water Polarity Causes :
1. H2O to be an effective solvent (splits
things dissolved in it). Universal solvent
 2. Surface tension – forming of a thin
layer caused by cohesion (attraction
between like molecules)
 3. Adhesion – attraction of different
molecules. Can cause capillarity (ability of
a liquid to be drawn up a tube)


4. Explains why H2O heats up and cools
down more slowly because you have to
use energy to break the bonds that are
sticking them together first then you can
get the molecules themselves to start
moving or slowing down.
-- this is what helps us maintain a
constant body temp (warm-blooded)
B. Carbon
- Forms covalent bonds (sharing)
- Can bond with itself to form straight,
branched, or ringed chains.
- These differences in bonding
arrangements provide the many
differences in living things.
*** Formation of carbon compounds
-- polymers – compound made up of
repeated linked units (monomers)
-- monomer – each unit of a polymer
-- macromolecule – large polymers

Linking of polymers
- condensation reaction – the joining of
monomers by releasing a water molecule.
Ex. Making muscle tissue
- hydrolysis reaction – the breaking down
of polymers into monomers by the
addition of a water molecule. Ex. digestion
II. Organic Compounds
1.
Carbohydrates – contain C, H, O in a ratio of
2H to 1 O.
a. Monosaccharides – simple sugars.
ratio of C to H to O is 1 to 2 to 1. (C6H12O6).
Ex. Glucose , fructose, galactose
(us)
(fruits) (milk)
* all 3 have same chemical formula but differ in
their structural arrangement – called isomers
B. Disaccharides – combining of 2
monosaccharides through a condensation reaction
ex. Sucrose (sugar,beets) – made of
fructose and glucose.
lactose(milk) – made of glucose and
galactose.
C. Polysaccharide – 3 or more
monosaccharides
Ex. glycogen (stored animal sugar),
starch (stored plant sugar), cellulose
(plant cell wall)
2. Lipids – fats, oils, and waxes
- do not dissolve in water
- larger # of C and H and smaller # of O than a
carbohydrate
- used to make cell membranes and organelle
membranes.
A. Fatty Acids
- monomer of a lipid
- made up of a long, straight hydrocarbon
chain with a carboxyl group (COOH) at one end
- carboxyl end is polar, hydrocarbon end is
nonpolar. In cell membranes the carboxyl
end is to the outside and the hydrocarbon
end is to the inside of the cell membrane.
B. Triglycerides
- made up of 3 fatty acids and one
molecule of glycerol
- unsaturated fat – liquid at room
temperature, (oils of plants) – contain
double-bonded carbons. C=C
- saturated fats – solids at room temperature.
(animal fats) – single-bonded carbons. C-C
C. Wax
- made up of one long fatty acid chain
and a long alcohol chain ( the length is
what determines how good a waterproofer
it is.)
D. Steroid – made up of 4-carbon rings
- considered a lipid because they do not
dissolve in water.
3. Proteins
- made of H, O, C, and N
- formed by the linking of monomers
called amino acids.
- most important organic compound in
body –makes up your structure
A. Amino Acids
- 20 total, similar in structure but
slightly different
- each amino acid has a C as the central
atom with 4 other atoms or groups attached
NH2 -- amine group
H --C – R group
C
O
(what differs in all 20 )
(Carboxyl group)
OH
B. Dipeptides – 2 amino acids joined by a
peptide bond.
- long chain of amino acids is a
polypeptide.
- Protein = 2 or more polypetides
C. Enzymes – proteins that act as catalysts
(substance that speeds up a chemical reaction
by lowering activation energy)
- substrate – the area on a molecule where the
enzyme attaches to.
4. Nucleic Acids – stores information in the
cell.
Types :
a. DNA (deoxyribonucleic acid) – contains
information for all cell activities. Doublestranded.
b. RNA (ribonucleic acid) – contains information
for only protein making. Single-stranded.
*** Nucleotide – monomer that makes up DNA
and RNA – 4 types – contains a phosphate
group, 5-carbon sugar, and a nitrogen base