Biology Lecture 3: Cell Division
Phospholipids: amphiphilic, polar and non-polar.
Fatty acids are non-polar and insoluble in water. Some fatty acids contain “kinks” due to double
bonds. “Kinks” cause the fatty acids not to pack well and less dense. These molecules tend to be
liquid at room temperature.
Clicker Question: Desaturases are enzymes that introduce double bonds into fatty acid chains. If a
bacterium moves from warmer to cooler water, what will happen to desaturase activity?
C. Stay the same.
Not all enzymes work better as the temperature rises. There many organisms that live in
Antarctic lakes that prefer colder temperatures.
Bacteria and Archaea are both Prokaryotic.
“Bacteria and Archaea are both Prokaryotic” slide: the picture of the cell was taken by an
electron microscope, more specifically transmission electron micrograph. It was made by taking
a small slice of the cell, staining the cell and shooting electrons through it.
Eukaryotes evolved infolding of the plasma membrane. Internal membranous organelles were
the result of endosymbiotic events. Some of the membranous organelles in a eukaryote used to
be free-living bacteria.
Ancestral plants acquired photosynthetic prokaryotes.
Eukaryotes are larger internally compartmentalized.
The cytoskeleton of a cell:
o Maintains cell shape.
o Important in cell motility
o Communicates from the cell surfa