Lecture 15 + 16, Membrane (Ford) Flashcards
T or F: Lipids are amphipathic.
True.
What does amiphipathic mean?
Having hydrophilic and hydrophobic parts
What is the basic structure of a general fatty acid?
Hydrocarbon + carboxyl
What is the primary hydrophobic determinant of a fatty acid?
Hydrocarbon + carboxyl
How does the melting point of saturated vs. unsaturated fatty acids compare?
Saturated = higher Unsaturated = lower
How does the flexibility of saturated vs. unsaturated fatty acids compare?
Saturated = high Unsaturated = low
What makes a fatty acid saturated or unsaturated?
Presence of a double bond (unsaturated)
How does the shape of the hydrocarbon of saturated vs. unsaturated fatty acids compare?
Saturated = linear Unsaturated = bent more or less
What is the dietary source of saturated vs. unsaturated fatty acids?
Saturated = animal fats Unsaturated = plant oils, processed fats
T or F: Longer fatty acids melt at lower temperatures than shorter fatty acids.
False. Shorter fatty acids melt at lower temperatures than longer fatty acids.
List examples of saturated fatty acids.
Lauric, myristic, palmitic, stearic, arachidic, behenic, lignoceric
List examples of unsaturated fatty acids.
Palmitoleic, oleic, linoleic, linolenic, arachidonic; EPA, DHA; Partially hydrogenated oils
Fatty acids form ___.
Micelles
How are fatty acid carbons numbered?
From carboxyl end to methyl end
Which part of the fatty acid name indicates the fatty acid is unsaturated?
cis- or trans-
Which part of the fatty acid name indicates where the double bond is located on an unsaturated fatty acid?
Delta#
What would indicate 4 double bonds in an unsaturated fatty acid?
tetra-en
What nomenclature would indicate a protonated/acid fatty acid?
-oic acid
What nomenclature would indicate a deprotonated/conjugate base fatty acid?
-oate
Which part of the fatty acid name indicates the fatty acid is saturated?
n-
What does the number in parentheses of a fatty acid name indicate?
Total number of carbons : Total number of double bonds
How are omega fatty acids named?
For the position of the double bond closest to the methyl end of the fatty acid
Which omega fatty acids can’t be synthesized by humans?
Linoleic acid and linolenic acid
What is ALA converted into? Is this an efficient process?
EPA and DHA; No, it is an inefficient process
Why are omega fatty acids important?
Used in cell membrane and other important lipids, common energy source, promote good health by improving cardiovascular health
What are the 2 parts of triacylglycerols?
Polar head = glycerol
Hydrophobic tails = 3 fatty acid chains
Describe the structure of waxes.
Similar to triacylglycerols, but have an alcohol head with fatty acid chains
Archaeal lipid membranes contain ___ fatty acids.
Branches
What are the 3 categories of cell membrane lipids?
Phospholipids, glycolipids, cholesterol
What is the majority component of cell membranes?
Glycerophospholipids
What are all the components of a glycerophospholipids?
Hydrophilic group, phosphate, glycerol, fatty acid chains
What are some common alcohols added to glycerophospholipids?
Amino acids (serine), sugar alcohols (inositol, glycerol), organics (ethanolamine, choline)
What attaches a fatty acid to an amine?
Sphingomyelin
What are glycosphingolipids important for?
ABO blood type antigens, cell signaling
T or F: Glycoglycerolipids are usually found in animals, but rarely in plants or bacteria.
False. Glycoglycerolipids are found in plants or bacteria, and rarely in animals.
What does cholesterol do for cell membranes?
Adds rigidity
How is a bilayer formed?
When multiple hydrocarbon tails are present
What is the dual role of a lipid bilayer?
2D liquid that allows the lateral movement of proteins and lipids, permeability barrier
Describe the Fluid Mosaic Model.
Cell membranes are made up of several different types of structures (lipids, proteins, carbohydrates) that allow for their flexible nature
What is the base component of the Fluid Mosaic Model?
Lipid bilayer
Where are carbohydrates presented on the cell membrane?
Not in contact with cytosol
T or F: Integral membrane proteins span the entire width of the lipid bilayer.
True.
Why is having membrane proteins with lots of hydrophobic amino acids displayed on their surfaces good and bad?
Good = feature of living in a hydrophobic environment Bad = if cytoplasm of cell is aqueous
What is a solution to the issue of integral membrane protein insertion?
Contralateral insertion
T or F: Membrane anchors are hydrophilic.
False. Membrane anchors are hydrophobic.
How much of the proteome do membrane proteins constitute?
30%
List some functions of membrane proteins.
Receive external signals, transmit signals to cytoplasm, transmit signals to another cell, allow solutes through membrane, help to determine membrane thickness and rigidity
What does it mean that lipids are 2D fluids?
Allow only lateral movement of components
In bacteria, what is the rigidity of the membrane determined by?
Fatty acid composition
In humans, what is the rigidity of the membrane determined by?
Cholesterol content
T or F: Membranes are asymmetrical.
True.
