This document discusses lipids, which are concentrated energy molecules that serve several functions in biology. Lipids include fats, oils, waxes, and hormones. They are used for energy storage and provide twice the energy of carbohydrates. Lipids also make up cell membranes and help cushion and insulate organs. Saturated fats from animals are solid at room temperature and contribute to heart disease, while unsaturated fats from plants and fish are liquid and are a healthier choice. Cell membranes contain phospholipids that form a barrier for the cell, with hydrophilic heads on the outside and hydrophobic tails on the inside.

1. Regents Biology 2003-2004
Lipids: Fats & Oils

2. Regents Biology 2003-2004
Lipids
Concentrated energy molecules

3. Regents Biology 2003-2004
Lipids
 Examples
 fats
 oils
 waxes
 hormones
 sex hormones
testosterone (male)
estrogen (female)

4. Regents Biology 2003-2004
Lipids
 Function:
 energy storage
 very concentrated
 twice the energy as carbohydrates!
 cell membrane
 cushions organs
 insulates body
 think whale blubber!

5. Regents Biology 2003-2004
Structure of Fat
not a chain (polymer) = just a “big fat molecule”

6. Regents Biology 2003-2004
Saturated fats
 Most animal fats
 solid at room
temperature
 Limit the amount
in your diet
 contributes to
heart disease
 deposits in
arteries

7. Regents Biology 2003-2004
Unsaturated fats
 Plant, vegetable & fish fats
 liquid at room
temperature
 the fat molecules
don’t stack tightly
together
 Better choice in your
diet

8. Regents Biology 2003-2004
Saturated vs. unsaturated
saturated unsaturated

9. Regents Biology 2003-2004
Other lipids in biology
 Cholesterol
 good molecule in cell membranes
 make hormones from it
 including sex hormones
 but too much cholesterol in blood may
lead to heart disease

10. Regents Biology 2003-2004
Other lipids in biology
 Cell membranes are made out of lipids
 phospholipids
 heads are on the outside touching water
 “like” water
 tails are on inside away from water
 “scared” of water
 forms a barrier
between the cell
& the outside

11. Regents Biology 2003-2004
Let’s build some
Lipids!