Lipids
Fats, Oils, waxes
Lipid Basics
Made of C,H,O
monomer = glycerol + fatty acids
hydrophobic - don’t dissolve in water
oil and water don’t mix
Fatty Acids
2 types – saturated and unsaturated
- What’s the difference?
- saturated fatty acids
No double bonds between C atoms
- holds the maximum # of Hatoms
- unsaturated fatty acids
contain double bondsbetween C atoms
Lipids- Fats and Oils
•
Fats & Oils (triglycerides)- long term energy storage
•Fat has twice the calories of carbohydrates.
– fat = 9 cal/g sugar= 4 cal/g
2-24
Health tip:
Saturated orhydrogenatedfats(bad) vs.unsaturated(good)
Lipids: types and functions
Fats/Oils – long term energy storage,insulation and protection
Phospholipids – cell membranes
Steroids – make hormones (chemicalmessengers)
Waxes – waterproofing
Fats (Saturated)
•Solid at room temperature
•Energy storage in animals
•contain saturated fatty acids
Saturated fat and fatty acid
Stearic acid
Body Fat – stores energy, insulates and protects the organs
Excess energy isconverted to fat
Sea mammals rely onfat to keep them warm
Oils (Unsaturated)
•energy storage in plants
•contain unsaturated fatty acids
•liquid at room temperature
Unsaturated fat and fatty acid
Double bond
causes molecule
to bend
Oleic acid
Phospholipids- create the structure of cellmembranes
•only 2 fatty acids (not 3 like fats and oils)
•3rd fatty acid is replaced by a phosphatemolecule
SPONCH
Phospholipid structure
Phosphate molecule forms a hydrophilic(water loving) head
•Fatty acid molecules make up ahydrophobic tails
CH2
O
P
O
O
O
CH2
CH
CH2
O
O
C
O
C
O
Phosphate
Glycerol
(a) Structural formula
(b) Space-filling model
Fatty acids
(c) Phospholipid
symbol
Hydrophobic tails
Hydrophilic
head
Hydrophobic
tails
–
Hydrophilic head
CH2
Choline
+
Figure 5.13
N(CH3)3
myelin - phospholipid that insulatesnerve cells
We are all literally “Fatheads”
Cholesterol
•component of cell membrane
•used to make steroids
Steroids: Lipids that act as Hormones
Hormones are chemical messengers
- produced in one part of the body, they travel to and
cause changes in another part of the body
- Hormones control:
growth
development
tissue function
sexual function
the way our bodies use food,
the reaction of our bodies to emergencies,
mood
- examples
estrogens
testosterone
Estrogen Testosterone
Waxes-Lipids that repel water
- found on the surface of leaves
- found on animal hair to keep it pliable
- found on the feathers of water birds to prevent themfrom becoming waterlogged
