lecture seven Flashcards
Fatty Acids
is a carboxyl group with hydrocarbon chain
Triglyceride
is a fat; glycerol molecule with three fatty acid tails. Function is to store energy and insulate
Phospholipid
two fatty acid tails with a polar head made of glycerol and phosphate group
What type of reaction is used to join a glycerol molecule to a Fatty Acid
Dehydration reaction
What is the difference between a saturated and unsaturated Fatty Acid
unsaturated have a double carbon bond that creates a kink, and in the membrane this keeps them from packing together and therefore enhances membrane fluidity
What are common modifications made to the Phosphate head of a Phospholipid
Phosphate group of phospholipid is attached to third hydroxyl group of the glycerol
What is the most well-known steroid?
Where in the cell is it synthesized?
-Cholesterol
ER
At a very general level, how is Cholesterol structure similar and different to a Phospholipid?
Both are amphiphilic.
Cholesterol is made of mostly carbon and hydrogen,
phospholipids have hydrocarbon tails
Proteins found on membrane
integral (spanning both sides)
and peripheral (one side)
glycoproteins
lipids on membrane
glycolipid
What are the two main types of lipids and what chemical characteristics come with their structure?
phospholipids have unsaturated tails- As the temperature decreases, the membrane remains fluid to a lower temperature if it is rich in phospholipids with unsaturated hydrocarbon tails
“fluidity buffer” for the membrane, resisting changes in membrane fluidity that can be caused by changes in temperature
What is the Fluid Mosaic Model?
Model of cell membrane structure, which envisions membrane as a mosaic of protein molecules drifting latterly in a fluid bilayer of phospholipids
How can the fluidity of a membrane be increased or decreased
High temp→ more fluid, low temp→ less fluid
Cholesterol buffers at both extremes
Is there a “sided-ness” to these fluid membranes
Yes-the outside and inside can differ in lipid composition, and each protein has directional orientation in the membrane.
What factors influence the permeability of the membrane
affected by lipid composition (saturated vs unsaturated-unsaturated increases permeability as they can’t pack together) and temp; cholesterol reduces gaps and lowers permeability to medium polar molecules.
