Organic Chemistry
Biologically Important
Molecules
Chemical Compounds in
Living Things
• Carbon, hydrogen, oxygen, and
nitrogen make up practically all the
chemical compounds in living things
• These 4 elements make up 96.3% of
the total weight of the human body.
2 Groups of Compounds
• Organic – compounds that
contain carbon; associated
with living organisms
• Inorganic- compounds that
do not contain carbon
Organic Compounds
• The name organic chemistry came
from the word organism.
• Organic chemistry deals with the
chemistry of carbon
There are more than 2 million carbon
compounds
Elements vs. Compounds
• Elements are made of one type of
atom
– Found on the Periodic Table
– Ex.- carbon, oxygen, nitrogen
• Compounds are a combination of 2
or more elements
– Ex.- water (H2O), carbon dioxide (CO2)
Polymerization
• Polymerization- chemical process
where small compounds are used to
build larger compounds
• monomers- smaller compounds;
building blocks (“puzzle pieces”)
• polymers- made up of a series of
monomers (the completed “puzzle”)
• macromolecules- extremely
large polymers; macro- means
giant
• The process of polymerization is
like using the alphabet
Compounds of Life
• Organic compounds found in
living things can be classified
into one of 4 major groups of
biological macromolecules:
– carbohydrates
– lipids
– proteins
– nucleic acids
Carbohydrates
Sugars and Starches
What are carbohydrates
used for?
ENERGY
STRUCTURE
Structure
• carbon, hydrogen, and oxygen
• two hydrogen atoms for every one
oxygen atom-- H:O = 2:1 always!
Carbohydrates
provide 4 calories
of energy per
gram.
Important Examples
glycogen
starch
cellulose
sugar
(glucose)
Monosaccharides
• monosaccharide- single, or simple, sugar;
the simplest carbohydrate
– All carbohydrates are built from
monosaccharides = monomers = building
blocks
– Energy source for cellular respiration
– Examples: glucose- “blood sugar”
fructose- found in fruits
galactose- found in milk
Glucose is the most important
monosaccharide on Earth.
Made during Photosynthesis
Used for energy during Cellular Respiration
Polysaccharides for Storage
• polysaccharides- long chains of
monosaccharides; very large
complex carbs
• excess sugar is stored in the form
of polysaccharides
– starch = stored sugar in plants
– glycogen = stored sugar in animals
(stored in liver and muscles)
Other Important Polysaccharides
• Cellulose is only found in plants
– Makes up plant cell walls to provides
strength and rigidity
– Major component of wood
• Chitin is the material that makes up
the exoskeletons of all arthropods
(insects, spiders, lobsters, etc.)
Lipids
AKA: Fats, Oils,
Waxes, Hormones
Overview
• fats and waxes tend to be solid at
room temperature
• oils tend to be liquids at room
temperature
• insoluble in water (hydrophobic)
Importance
The body uses fat as a
long-term energy
storage.
9 calories/gram
Importance
• forms cell membranes
• stored, backup energy
• provides insulation- regulates body
temperature
• help the body use vitamins
• cushions organs
• function as messengers
• promotes healthy skin
• Bonus- Taste great!
Structure
• mostly carbon & hydrogen
– small amount of oxygen
– no ratio
• Made up of fatty acids = building
blocks = monomers
– Fatty acids make the fats non-polar and
hydrophobic
Triglycerides
• most of the fat in your body is
in the form of triglycerides
(~97%)
• any lipid made up of 3 fatty
acids
Ex.- Phospholipids
• a phosphate group replaces
the third fatty acid
• makes up the structure of cell
membranes (phospholipid
bilayer)
Phospholipids cont.
• have a hydrophillic “head”
(phosphate)
• have a hydrophobic “tail”
• hydrophillic- water loving
• hydrophobic- water fearing
• soluble in water
Ex.- Sterols
• Cholesterol is one of the most common
sterols
– Cholesterol is important to the structure of brain and
nerve cells
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Used to make bile (for digestion)
Part of vitamin D
Help carry messages in the body
Help form steroid hormones such as
cortisol, testosterone, and progesterone
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Ex.- Waxes
coat and protect things in nature
bees make wax
our ears make wax
plant leaves have a waxy coating on
the outside to prevent water loss =
transpiration