1. Lipids
Biomolecule #2

2. Lipid Structure
Lipids are molecules made mostly of carbon, hydrogen, and very few oxygen. The ratio of hydrogen to oxygen is greater than 2:1
The monomer of a lipid is made up of glycerol and fatty acids.
Lipids generally form long chains except in steroids.
Lipids are hydrophobic. Lipids do not dissolve in water.

3. Lipid Structure: Saturated vs. Unsaturated
Fatty Acid Type
Drawing
Food examples:
Saturated
solid at room temperature
(no double bonds = bad)
Unsaturated
liquid at room temperature
(double bonds = good)
Peanut Butter
Meat
Butter
Olive oil
Avocado
Fish

4. Lipid Functions Energy storage for the body (long term energy)
Insulation
Cell membrane structure (phospholipid bilayer)
Chemical messengers that carry messages through the blood stream.
Protection against water lose; waterproofing.

5. 1. Fats: Triglycerides found in foods and the human body.
Examples of Lipids
1. Fats: Triglycerides found in foods and the human body.
Solid at room temperature
Energy storage in animals
Contain 3 saturated fatty acids
Saturated fat and fatty acid
Stearic acid

6. Body Fat – stores energy, insulates and protects the organs
Excess energy is converted to fat
Sea mammals rely on fat to keep warm

7. 2. Oils: Triglycerides found in plants.
energy storage in plants
contain 3 unsaturated fatty acids
liquid at room temperature
Unsaturated fat and fatty acid
Double bond
causes molecule
to bend
Oleic acid

8. 3. 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 them from becoming waterlogged

9. 4. Phospholipids Glycerol
only 2 fatty acids (not 3 like fats and oils)
3rd fatty acid is replaced by a phosphate molecule
Please draw and label the phospholipid.

10. (a) Structural formula (b) Space-filling model
Phospholipid structure
Phosphate molecule forms a hydrophilic (water loving) head
Fatty acid molecules make up a hydrophobic tails
CH2 O P CH C
Phosphate
Glycerol
(a) Structural formula
(b) Space-filling model
Fatty acids
(c) Phospholipid
symbol
Hydrophobic tails
Hydrophilic
head
Hydrophobic
tails –
Hydrophilic head
Choline +
Figure 5.13
N(CH3)3 10

11. Phospholipids create the structure of cell membranes
2 layers of phospholipids
Phosphates face out – interact with water
Lipid tails make a middle layer that repels water
Phospholipids separate the contents of the cell from it’s surrounding environment
Hydrophilic
head
WATER
Hydrophobic
tail 11

12. Myelin - phospholipid that insulates nerve cells

13. 5. Cholesterol connected rings of carbon
component of cell membrane – adds to the integrity of the membrane
used to make steroids

14. 6. 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:
mood
growth
development
the way our bodies use food
the reaction of our bodies to emergencies

15. Steroids are Derived From Cholesterol
Estrogen Testosterone