Name______Answer Key__________________ Date_______________ Period_____________
LIPIDS WS
Bio I, Ms. D
1. Below draw a SATURATED fatty acid and an UNSATURATED fatty acid. 2. Why is the SATURATED fatty acid called “saturated?” What is it saturated with?
Saturated fatty acid have the most amount of hydrogen atoms that they can possibly
have. So they are saturated with hydrogen.
3. Why do saturated fatty acids have more of tendency to clog arteries than unsaturated fats?
The molecular structure of saturated fatty acids is more condensed. There is less space
between the fatty acid tails. Therefore, saturated fatty acids have a tendency to be
more solid or “goopy.” Because they are “goopy” they stick to the walls of your arteries
causing a clog.
4. List the FOUR different kinds of lipids.
Triglycerides
Phospholipids
Waxes
Steroids
5. Draw a triglyceride and label the parts of the molecule. (You get to choose whether you draw a
saturated or unsaturated triglyceride  )
6. What is the main function of triglycerides? They are long term energy storage in plants
& animals
7. Draw a phospholipid and label the parts of the molecule. 8. What is the main function of phospholipids?
They create a barrier between the inside of the cell and the outside of the cell
called the cell membrane. The cell membrane is a phospholipid bilayer.
9. Draw a typical phospholipid bilayer. Label the extracellular side, the intracellular side,
hydrophobic areas, and hydrophilic areas.
10. How does the STRUCTURE of a phospholipid make it good for its FUNCTION in the cell
membrane? A phospholipid has both a polar, hydrophilic head and non-polar,
hydrophobic tails. Since there is aqueous solution both inside and outside the
cell, the polar head can interact with the aqueous solution, while the
hydrophobic tails make up the actual barrier between inside and outside of the
cell.
11. What’s the function of ear wax? Ear wax is a waterproof barrier that helps to prevent
dirt, dust, bacteria and bugs from getting inside the ear.
12.
What the function of wax on plant leaves? Plant leaf wax provides a waterproof
barrier on the surface of plants that live in dry climates. It prevents the leaves
from losing too much water.
13.
How does the STRUCTURE of wax make it good for its FUNCTIONS? A wax is a lipid
and has large hydrophobic parts to the molecule. The hydrophobic parts repel
water, allowing wax to create a waterproof barrier.
14.
What do all steroid molecular structures have in common? All steroids have a
molecular structure that includes 4 carbon rings.
15. What is the important function of cholesterol in all cells?
Cholesterol provides structure and rigidity to the cell membrane.