Biochem quiz 2_-lipids

Saturated vs unsaturated

Sat- non double bonds.

Unsat- double bonds

Kink created by double bonds

increases membrane fluidity and lowers Tm

Which fatty acids are susceptible to oxidation

• unsaturated fatty acids

Storage lipids

Triglycerides

• 3 fatty acids

• attached to glycerole

Membrane lipids: Glycerolephospholipids

• 2 fatty acids

• attached to glycerole

• ester bonds

Membrane lipids: Sphingolipids

• 1 fatty acid

• peptide or amide bond

Cholesterol

Only present in animals, evolved when oxygen became prevalent in the atmosphere, affects the polarity of the membrane (more difficult for ions to permeate

Hop diffusion

Lipids do not stay static, they hop around the membrane

Rafts

areas on the membrane that are rich in cholesterol to organize cell signaling and transport

Exosomes/endosomes

shedding cells create exosomes that contain microRNA and proteins. Diffuses through the interstitial space

Micelle

single lipid layer

hydrophobic interer

Liposome

lipid bilayer

surrounds an aqueous core

Why are liposomes important

accommodates both hydrophilic (aqueous core) and hydrophobic drugs (lipid bilayer)

RNA packaging

• RNA are mixed with lipids

• Lipids assemble around RNA

  • Onpatro-siRNA

• Creates a lipid nanoparticle capable of carrying the nucleic acid

DSPC (lipid component)

Promotes membrane structure

Cholesterol (lipid component)

Stabilizes particle in physiologic fluids

PEG-liquid (lipid component)

Prevents aggregation in blood and during production

Cationic/ionizable lipid (lipid component)

Binds mRNA and facilitates endosomal escape

PEG problem

• anti-PEF antibodies that can either exist before treatment/exposure or can contribute to HSR