Biology Lecture 2: Cell Biology
Water is polar; molecules attract.
Fatty acids are non-polar and insoluble in water.
Q. Why does mayonnaise separate?
o Mayo contains eggs that are “amphiphilic”, having both hydrophobic and hydrophilic
regions. Eggs are full of phospholipids (containing the hydrophobic and hydrophilic
Phospholipids have a polar region that is hydrophilic, and a non-polar region that is
Membranes are formed by lipid bilayers.
Clicker Question: Which of the following easily cross the membranes (without help)?
B. O 2
C. Na + (ions, or charged molecules do not cross membranes by itself. They use channels.)