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Organic Molecules of Life
Fundamental: all life is interconnected because it
uses a monomer to build larger, more complex
polymer!
• Elements form molecules
- All organic molecules are made of the elements
Carbon (C) and Hydrogen (H)
- Can exist in a chain or a ring
• Everything that happens in our body is due to
changes in levels of molecules:
1) make new molecules
2) maintain existing molecules
3) dispose of dead molecules
Examples - molecules
Ionic bond – NaCl – SALT
transfer of an electron
Covalent bond – CH4 – METHANE
sharing of electron(s)
First consider…Inorganic molecules
(non-living…and water soluble)
• Inorganic molecules DO NOT CONTAIN C and H
(thus, water is IS NOT an organic molecule
despite being critical to life)
• Inorganics, in living systems, are important
NaCl = sodium chloride
KCl = potassium chloride
CaCl2 = calcium chloride
MgCl2 = magnesium chloride
HCl = hydrochloric acid
NaOH = sodium hydroxide
• Salts in water dissociate, creating charged molecules (ex. Na+,
H+, Cl-)
• Therefore, because these molecules are charged, they are ions
in water
Carbon is key for organic molecules
• Contains only 6 electrons (2 in inner shell, 4 in outer
shell…leaves 4 open slots
• Means one atom of C can bond with up with up to 4
other atoms
• Can bond up with other C atoms:
 make long carbon chain (ex: octane)
 can produce rings (ex: cyclohexane)
Carbon Skeleton &
Function Groups
• Carbon skeleton =carbon chain of an organic molecule.
Accounts for the shape of the organic molecule
• Functional group = a specific combination of bonded
atoms that always reacts in the same way, regardless of
the carbon skeleton
• See image at bottom of pp 13 in packet
Functional Group examples:
Carboxyl
(acidic)
present in
amino acids,
fatty acids
Amino
present in
amino acids
R = remainder of molecule
Organic molecules = Living molecules
(associated with living organisms)
• Organic molecules ALWAYS contain C and H
• Long known as “macromolecules”
• Four basic types:
Building blocks that
 Proteins
make up these are called
MONOMERS
 Polysaccharides
Amino Acids
 Fats/Lipids/Membranes
Sugars/Carbs
 Nucleic acids
Fatty Acids
Nucleic Acids
Carbohydrates: ORGANIC MOLECULES
- Macromolecule that functions for quick fuel and shortterm energy storage in organisms
• Building block for carbohydrates = monosaccharides
(monosaccharides = MS)
• One major MS is glucose= “hexose”, blood sugar,
immediate source of energy
• MS + MS = disaccharide
– Example= maltose (2 glucose sugars after dehydration rxn)
– Sucrose (glucose and fructose)
• MS+MS+MS+etc. = polysaccaride (not so “simple” sugar)
– Example= starch, glycogen, and cellulose
Functions of Carbohydrates
• Primary functions
 Food source
 attached to proteins to create glycoproteins
Membrane proteins important for cell-to-cell
interactions and communication
 Structure of plant cells (cellulose) and
exoskeletons (chitin)
Carbohydrates: PRIMARY FUNCTIONS con’t
Energy source: eat
carbohydrates and
get glucose, store
as glycogen (a
polysaccharide) in the
liver until body needs
it for energy. Glucose
is used by cells for
“energy” to run.
In-between eating,
liver releases glucose
so blood glucose level
is always 0.1%
(Mader p43
Fig. 3.8b)
Carbohydrates: PRIMARY FUNCTIONS con’t
Structure of Cells: combine with other molecules.
A)Plants –cellulose in cell walls provides rigidity
B) Insects—chitin…hard covering on beetles, etc.
(Mader p44
Fig. 3.9)
How can you identify a carb?
• Atomic grouping H – C – OH
• 2:1 hydrogen to oxygen ratio, rings
• “hydrates of carbon”
Lipids: ORGANIC MOLECULES
• Do not dissolve in water (hydrophobic)
• 4 types: A) Fats and oilstriglycerides, neutral lipids)
- Tricglycerides= Three-part structure
- “Neutral fat” b/c nonpolar
- Emulsification= oil disperses in water
ex: dirty clothes in laundry
•
• B) Saturated and unsaturated fats—longchain fatty acids bond with long-chain
alcohols. Solid at normal temps
– Fatty Acid= hydrocarbon chain that ends with the
acidic group –COOH
– Contain 16-18 C per chain
– Saturated= no double bonds, max # of hydrogens
-- - - Unsaturated= double bonds between
carbons
Saturated v. Unsaturated
http://www.youtube.com/watch?v=crYNIlcU
OiE
• C) Phospholipids (same as neutral lipids
with extra molecules, thus made up of
fatty acids, too.
– One end soluble in water, other isn’t
– —important in cell membranes
Phospholipid structure
• D) Steroid—ring structure results in “rigid”
molecule. Not soluble in water
– Backbone of 4 fused carbon rings
– Ex: cholesterol= component of cell membrane
and precursor to other steroids
• Bile salts, testosterone, estrogen
– Too much cholesterol= reduced blood flow
Cholesterol
Lipids: ORGANIC MOLECULES
Primary functions
 Energy source (long-term storage in body = fat, in
plants = oils)
 make-up cell plasma membrane (phospholipids) –
absolutely essential to structure and function of cells
 Hormones (steroids): testosterone, estrogen, anabolic
steroids.
Lipids: PHOSPHOLIPIDS FORM MEMBRANES
Polar & Nonpolar ends:
Polar “head” is hydrophilic
(i.e., water loving) and
therefore, soluble in water
Non-polar “tail” groups are
hydrophobic and therefore,
not soluble in water
Plasma membrane of cell
(Mader p48
Fig. 3.11)
Lipids: GOOD & BAD FATTY ACIDS ????
% of saturated and unsaturated fatty acids in fats and oils
Saturated fats associated with cardiovascular disease
(Mader 6th edition
p36,
Fig. 3.13)
Lipids: ORGANIC MOLECULES
Waxes -- examples
• protect fruit
• “comb” portion of bee hive to store honey
• human ear wax – traps dust & dirt
Proteins: ORGANIC MOLECULES
• Building block for proteins = Amino acid
• Amino Acids= central carbon atom bonded to H
and 3 groups
• R-group is important b/c: Identifies which protein
is present
Proteins: functions
• Primary functions
 Keratin (support)—hair, nails, collagen, ligaments,
tendons, skin
 Hormones (metabolism)—speed up chemical
reactions
 Actin and myosin- responsible for muscle contraction
 Antibodies (defense)—fight infection, pathogens
 Transport proteins—molecules across membranes (ex.
RBC)
 Enzymes—speed up chemical reactions
Proteins: examples of support, transport, & defense
Spider web
Hemoglobin in RBC
Cytotoxic T cells
(10,000 X)
Protein Bonds
• AA + AA = Peptide bond= joins any two amino
acids togenter
• AA+AA+AA+etc. = polypeptide (complex protein)
Proteins: Shapes
• 4 Structural Levels
 Primary
 Secondary
 Tertiary
 Quaternary
(Mader p52, Fig. 3.16)
Nucleic Acids: ORGANIC MOLECULES
• Form chains by combining Sugar, phosphate, and a
nitrogenous base- Soluble in water!
• DNA = Deoxyribonucleic acid (sugar= deoxyribose)
(genetic info)
• RNA = Ribonucleic acid (sugar=ribose) (info for protein
synthesis)
– Phosphate= phosphoric acid
– Pentose (5) sugar= deoxyribose or ribose
• Building block for nucleic acids = A, G, C, T
• 4 basic nucleotides in DNA: adenine, guanine, cytosine,
thymine (G-C, A-T…base pairings)
• 4 basic nucleotides in RNA: adenine, guanine, cytosine,
uracil (G-C, A-U…base pairings)
Nucleic Acids: DNA & RNA
DNA with base pairs G & C, A & T
RNA with base pairs G & C, A & U
(Mader p219, Fig. 12.5)
Nucleic Acids: ORGANIC MOLECULES
• Primary functions - ____________
 Protein synthesis – genes…contain all the information
needed to duplicate cells (i.e., “blueprints”). Genes
specify sequence of amino acids in proteins
 Gene expression–important for determining
phenotypes of organism
3. ATP—how cells store energy for their use …ATP is the
energy carrier of cells
(ATP =
adenosine triphosphate)
Sickle Cell Disease
Quick Summary – 4 Organic Molecules
Organic Molecule type Soluble in water?
CARBOHYDRATES
LIPIDS
PROTEINS
NUCLEIC ACIDS
Building blocks
Important to Reactions p. 31
Dehydration
• Removal of a water
molecule
• Uses monomers
(subunits) together to
form polymers (large
macromolecules
• Ex. Polymerization of
glucose monomers to
make starch
Hydrolysis
• Addition of a water
molecule
• Used to disassemble
polymers into monomer
parts
• Ex. Digestion of starch
into glucose monomers
Water! – KEY TO THESE REACTIONS.
1) Used in the REACTION BUT
2) Conserved IN THE PROCESS