Chapter 9 Flashcards
What is the naming/numbering system for fatty acids?
18:1∆^9 means there are 18 carbons, 1 double bond, and 9 is where the double bond occurs. Omega occurs when carbons are counted from methyl (omega) end instead of carboxylic acid end, only when there’s omega 3 or 6.
What are the physical properties of fatty acids?
Saturated FAs aren’t soluble in water, PUFAS (Dietary polyunsaturated fatty acids) are slightly more soluble.
Melting points of FAs are influenced by the length of the FA and the saturation level. Saturated FAs have a higher melting point than unsaturated FAs. This is because of the tight packing of saturated FAs vs. the loose association of unsaturated FAs. The longer the chain, the higher the melting point.
What is the difference between ether-linked and ester-linked fatty acids?
Ether-linked FAs can’t be hydrolyzed, making them way more stable. Ester-linked FAs can be hydrolyzed, and they are less stable.
What is Tay-Sachs Disease?
The accumulation of a ganglioside in the brain and spleen which leads to mental retardation and early death.
What are sterols?
Structural lipids present in the membranes of most eukaryotic cells. Cholesterol is a major sterol, its structure is made up of four rings and it has a polar group. Other sterols include steroid hormones and bile acids.
What is Vitamin A and its structure?
Beta-carotene is the precursor of vitamin A. Cleavage of Beta-carotene yields two molecules of vitamin A1 (retinol). Makes beneficial products to help eye health and vision
What are the three structural lipids in the membrane and do they do?
Flippase, floppase, and scramblase.
Flippase moves PE and PS from the outer cytosolic leaflet.
Floppase moves phospholipids from cytosolic to the outer leaflet.
Scramblase moves lipids in either direction, toward equilibrium.
These structural lipids are always in motion/moving.
What are transmembrane proteins? How do you analyze them?
Transmembrane proteins are proteins that extend through the bilayer with/ part of their mass on either side. -are amphipathic. -hydrophobic parts (side chains) interact with hydrophobic tails of lipids. -hydrophilic parts are exposed on both sides of the membrane. They are very difficult to crystallize and hard to get a structure for. Hydropathy plots are used to analyze.
What are three types of membrane proteins?
Integral membrane proteins- firmly associated with the lipid bilayer, can be removed by any chemical or treatment that disrupts the hydrophobic interactions (like detergents).
Peripheral membrane proteins-
associate with the membrane through electrostatic interactions and hydrogen bonding with hydrophilic domains of integral proteins and with the polar head groups of membrane lipids.
Amphitropic proteins- found in cytosol, in association with membranes. They have noncovalent interactions with the membrane proteins, their association is regulated by, for instance, phosphorylation.
What is the prevalence of amino acids in membrane proteins?
Membrane proteins have specific amino acids.
Nonpolar region of acyl chains meet polar head group region- residues of Tyr and Trp are mostly found.
Charged residues (Lys, Arg, Glu, Asp) found almost exclusively in the aqueous phase.
Outside- charged or uncharged polar
Inside- Aromatic amino acids
