Lectures 15-16: Lipid and Cell Membrane Structure Flashcards
What are the basics of the structure of a fatty acid?
Hydrocarbon+carboxyl
Primary HYDROPHIBIC determinant
can be saturated or unsaturated (double bond)
Describe a fatty acid who melts at a lower boiling point and is not very flexible
Unsaturated
What is the relationship between the length of a fatty acid and the temperature at which it melts?
Proportional: Shorter fatty acids melt at lower temperature
Describe all of the necessary components that are needed in order to name a fatty acid
- need to know if it is cis or trans
- need to know if there are any double bonds in the molecule and what carbons they are between
- the number of the hydrocarbon chain
- level of saturation
- what functional groups are in the fatty acid
If you have a fatty acid that is deprotonated, what will the suffix of that molecule be?
-oate
How many carbons and double bonds is in stearate?
18:0
How many carbons and double bonds is in Oleate?
18:1
How many carbons and double bonds is in Linoleate?
18:2
How many carbons and double bonds is in Linolenate?
18:3
How do you tell the difference between Omega 3 fatty acids and Omega 6 fatty acids?
By where the double bonds are positioned in the molecule
3 vs. 6
List the Omega 3 fatty acids
Linolenic Acid Stearidonic Acid Docosapentaenoic Acid Eicosapentaenoic Acid Docosahexaenoic Acid
Define ALA
Linolenic Acid (18:3)
Define SDA
Stearidonic Acid (18:4)
Define DPA
Docosapentaenoic Acid (22:5)
Define EPA
Eicosapentaenoic Acid (20:5)
Define DHA
Docosahexaenoic Acid (22:6)
Define LA
Linoleic Acid (18:2)
Define AA
Archidonic Acid (20:4)
What are the two omega acids that cannot be synthesized by humans?
LA (18:2/w6)
ALA (18:3/w3)
What are the two fatty acids that ALA can be converted into? (inefficiently)?
EPA( 20:5/w3)
DHA (22:6/w3)
Why are omega fatty acids important?
- Used in the cell membrane and other important lipids
- are a common energy source
- promote good health via CV
Describe triacylglycerols
have 2 parts, polar head of glycerol and hydrophobic tail that is made up of 3 fatty acid chains
Describe waxes
They have a polar head of alcohol and a hydrophobic tail made up of fatty acids chains
What are the 3 categories of cell lipid membranes?
- phospholipids
- glycolipids
- cholesterol
Describe the structure and function of glycerophospholipids
make up the majority of the cell membranes; include a hydrophilic group, a phosphate, glycerol, and fatty acids
What are the common alcohols that are added to glycerophospholipids?
- amino acid
- sugar alcohols
- organics
- serine
- inositol, glycerol
- ethanol amine, choline
Describe sphingomyelin
fatty acid attached to an amine
Why are glycoshingolipids important?
ABO blood type antigens
cell signaling
Describe carbohydrates in the membrane
they “decorate” lipids and proteins but are only on the surface, and not in contact with the cytosol at all
Describe integral membrane proteins
have hydrophobic amino acids that can create a hydrophobic environment; they span the bilayer
They can insert via cotranslational insertion, which involves a ribosome and a translocon channel that is able to insert and fold the protein into the membrane
Describe peripheral proteins
span only PART of the lipid bilayer and their anchors are hydrophobic
soluble proteins are able to associate with the membrane IF the hydrophobic groups are attached to the proteins
What are the functions of membrane proteins ?
- receive external signals
- transmit in
- transmit to another cell
- let solutes pass
- determine the thickness and rigidity
Describe the concept of lateral diffusion as it relates to membrane proteins
The membrane proteins are always in lateral motion, the fluid mosaic model allows lateral movement but no rotation, so she’s always hula dancing almost
Compare the rigidity between human and bacteria membranes
in bacteria, the rigidity is determined by the fatty acid composition
in humans its all about the cholesterol (can combine to make lipid rafts)
