LIPIDS
LIPIDS
•Fats, oils, phospholipids,
steroids & waxes
•Composed of C, H, O
(but fewer O than carbs)
– Chains of C atoms
bonded to each other and
to H atoms.
Lipids are HYDROPHOBIC!
“Water fearing”(b/c of non-polar
C-H bonds in the tail)
3 Major Roles of Lipids:
#1: Used as long-term
energy storage.
Adipose cells: (fat
cells) store energy,
cushion vital organs,
and insulate the
body.
• Fats store energy more efficiently
than carbs. (They have more H
bonds!)
• Many organisms can survive w/o
steady diets because of stored fat.
When there’s lots of food, animals convert
excess food into fats.
When food is scarce, these can be broken
down for energy.
#2: Form biological
membranes & control
water movement.
– Cell membranes are made
up of phospholipids. One
end likes water, one end
is repelled by water.
– Waxy surface on plants
controls water loss.
•#3: Used as chemical messengers.
– Ex. Steroids (testosterone &
estrogen)
Testosterone
MONOMERS
• Lipids are made up of fatty acids
• Fatty Acids - long chains of C & H
atoms that have a carboxyl group
(-COOH) at one end.
- polar
- hydrophilic  “water loving”
• Have a hydrocarbon group at the other
end (CH3)
– Nonpolar
– Hydrophobic
•Saturated Fats= All C atoms are
bonded by a single bond,
holding the max number of H
atoms.
•Commonly found in dairy
products and meats.
•Unsaturated Fats = A pair of
carbon atoms is joined by a
double bond, it doesn’t
contain the max number of H
atoms.
•Changes the shape, by adding
a “kink”
•Polyunsaturated = Contains
multiple double bonds.
Will be oil at room temp,
such as peanut and corn oil.
Phospholipids
• Consist of hydrophilic and hydrophobic
regions.
– Made up of only two fatty acids, instead of
three.
– Make up cell membranes.