Lipids and Membranes Flashcards
Fatty acids
Amphipathic, may be saturated or unsaturated
Oleic acid
one cis double bond
linoleic acid
two cows double bond separated by 3 carbons (unconjugated)
Reaction of fatty acid with NaOH
Produce a soap
Omega nomenclature
Start counting at tail
# of carbons : position of DB 1 (n-3)
Delta nomenclature
Assume cis, unconjugated
number of carbons : number of double bonds (list positions of DBs)
Most FAs are esterified to:
cholesterol or glycerol, or are found bound to albumin in the blood since they are so hydrophobic they need creative methods for transport
Arachidonic acid precursor to:
eicosanoids
eicosanoids
Bioactive FAs such as prostaglandins, thromboxanes, and leukotrienes.
Waxes
FAs esterified to a long chain alcohol which is very hydrophobic - waxy coating on leaves.
Triglycerides
-leoyl, three acts chains esterified to a glyceride.
Circulate as lipoproteins or lipid droplets
Major energy reserve of the body,hydrolysis releases FFAs.
Glycerophospholipids
Esters of 3-glycerophospahte, two FAs and a polar head group. Major component of membranes, vesicles
Lyso-PLs
Only one fatty acid
Phospholipids are precursors of
Lipid second messengers such as PIP2 being cleaved by phospholipids to generate DAG and IP3
Sphingomyelin and glycosphingolipids
Sphingosine backbone instead of glycerol, only one fatty acid, and varying polar head groups.
A sugar head - ganglioside, cerebroside, important in brain function for cellular recognition.
Genetic disorders of glycosphingolipid degradation
genetic defects in lysosomal GSL degradation causes severe neut degenerative diseases because they are involved in very specific pathways.
Cholesterol and isoprenoids
Derivedfrom diet or endogenously made from isoprene.
Highly insoluble, must be transported in lipoproteins
Imbalance of cholesterol causes:
Atherosclerosis and vascular diseases
Cholesterol regulation
intercellular transport and regulation by liver.
excreted rather than degraded.
Lipoproteins
Allow for triacylglycerols and cholesterols to move through circulation. Hydrophobic interior and polar outside - kinda like a micelle. Stored in adipose tissues.
Cholesterol is a precursor to
Bile acids, steroid hormones, and vitamin D
Isoprenoid examples
dolichol and ubiquinone
Phospholipids form ______ and _____ in water
Vesicles and bilayers
Micelles are formed by
Free fatty acids, and lyso-PLs (one acyl chain is smaller than the head group - makes a wedge)
Monolayers are formed by
The air water interface of a detergent, hydrophobic air interacts with nonpolar groups, whist polar head interacts with water.
Membrane fluidity _______ with degree of chain unsaturation, and _______ with fatty acid chain length
increases; decreases
Integral membrane proteins include?
why are they special?
α-helices and β-barrels, very special as they have hydrophobic amino acids to allow them to penetrate the hydrophobic interior of the bilayer.
Sequence-based prediction of α-helical proteins
Stretch of about 20 non-polar amino acids corresponds with the thickness of the bilayer and gives the structure of the protein that can sit within the membrane - genomics in determining function and cellular location.
