Lecture 1 Flashcards
Lipids highly diverse molecules known for their role in the formation of
biological membranes, cellular systems & storing energy.
Lipids also play an important role in
apoptosis, cell signalling, inflammation, immunity & inborn errors of metabolism (IEMs).
Inborn errors of lipoprotein metabolism result in
group of genetic disorders exemplified by changes in plasma lipids resulting from defects in protein-lipid carriers (lipoproteins), lipoprotein receptors, or enzymes responsible for the hydrolysis & clearance of lipoprotein-lipid complexes
LIPID CLASSIFICATIONS
The proteins maintaining normal plasma & tissue lipids
Are primarily triglycerides & free, & esterified cholesterol
- apolipoproteins AI, AII,B, CI, CII, CIII, D & E
The enzymes include:
(maintaining normal plasma & tissue lipids)
lipoprotein lipase (LPL),
hepatic triglyceride lipase (LIPC),
lecithin cholesterol acyltransferase (LCAT)
cholesterol ester transfer protein (CETP)
The receptors include
(maintaining normal plasma & tissue lipids)
low-density lipoprotein receptor (LDL-R) for LDL-cholesterol (LDL-c)
ATP-binding cassette transporter 1 (ABC1A) for HDL-cholesterol (HDL-c)
Fats & lipids are soluble in
organic solvents such as acetone, ether, & chloroform.
Fats & lipids vary considerably in size & polarity
hydrophobic triglycerides (TGs) & sterol esters
phospholipids (PLs) & cardiolipins.
Dietary lipids:
cholesterol (CH) & phytosterols.
What results in the specialized processing of lipids during digestion, absorption, transport, storage, & utilization
their non-water miscibility
largest proportion of dietary lipids consumed by humans.
TGs, or triacylglycerols
A TG is composed of
3 FAs esterified to 1 glycerol molecule
Phospholipids (PLs)
Limited quantities of dietary lipids occur as PLs
PLs differ from TGs
How
polar head groups - amphipathic properties to the molecule.
What are PLs
insoluble amphiphiles with a hydrophilic, often zwitterionic (containing both + & - charge) head group & hydrophobic tails composed of 2 longer chain FAs
PL Head groups are attached to the primary glycerol moiety via
phosphate linkages.
Polar head groups of PLs vary in size, charge
include inositol, choline, serine, ethanolamine & glycerol.
CH in the diet
free form & esterified to FAs
CH only in foods of
animal origin
plant oils are CH free
Plant materials contain
phytosterols
(chemically related to CH)
Dietary phytosterols include:
