270-279 Flashcards
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Heme is a
Heme is a cyclic structure
composed of four pyrrole
rings with a central iron atom.
hemoglobin
Stores O2 in muscle.
■ Similar structure to hemoglobin
Contains only one heme: can only associate with one O2 molecule.
■ Has much higher affinity for O2 than hemoglobin
hemoglobin
https://drive.google.com/open?id=0B8uJUY-tie8GdFRUWndWaG1kMXc
https://drive.google.com/open?id=0B8uJUY-tie8GQy1HUi01MWlCcUE
lipid
Highly hydrophobic molecules.
■ Soluble in nonpolar solvents such as chloroform, ether, and other organic
solvents.
lipid
Cellular structure
■ Metabolism
■ Transportation
■ Storage
■ All are aliphatic (non-aromatic) carboxylic acids
FA
Basic building blocks of most lipids
FA
Most are esters, although some exist as unesterified free fatty acids.
FA
The carbon chain can be saturated or unsaturated.
■ Have an even number of carbon atoms with a terminal carboxyl group.
FA
FA
Most are nonessential (can be synthesized
Linolenic acid:
■ Linoleic acid:
■ Oleic acid:
■ Arachidonic acids
Linolenic acid: ω-3 fatty acid
■ Linoleic acid: ω-6 fatty acid
■ Oleic acid: ω-9 fatty acid
■ Arachidonic acids
FA
Only a few are essential (found in vegetable oils and animal fats):
Saturated:
No double bonds.
Monounsaturated:
One double bond, usually in “cis” configuarion
Polyunsaturated:
Multiple double bonds.
lipid type
Triacylglycerols
■ Phospholipids
■ Steroids
■ Eicosanoids
TG
Consists of three fatty acids acylated to a glycerol molecule.
TG
Important source of energy.
■ Stored in adipose tissu
tg
Transported in the plasma by lipoproteins.
■
TG
Increased TGs linked to atherosclerosis, heart disease, and stroke.
phospholiid
Consists of two fatty acids acylated to two carbons of a glycerol molecule
and a phosphate group esterified to the third carbon.
phospholipid
Hydrophilic head (phosphate group); hydrophobic tail (fatty acids
phospholipid
Derive from phosphatate.
■ Major constituents of cell and mitochondrial membranes.
phospholipid
Precursors for second messengers and metabolic intermediates.
phospholipid
Increased TGs linked to atherosclerosis, heart disease, and stroke.
https://drive.google.com/open?id=0B8uJUY-tie8GcHUtaThKY3M2Y28
https://drive.google.com/open?id=0B8uJUY-tie8GUlpOVm5CUXF0NnM
choline
■ N+(CH3)3-CH2-CH2-OH
choline
An essential nutrient.
■ Found mostly in phospholipids.
■ Found as lecithin in plasma cell membrane.
choline
Precursor of betaine, an osmolyte used by kidney to control water balance.
cholin3
Component of sphingomyelin, which forms myelin sheath. Insulates nerve
fibers and aids in rapid conduction on nerve impulses
choline
■ Source of methyl group required for lipoprotein formation in liver.
■
choline
Necessary for acetylcholine formation.
■ Active component of lung surfactant
steroids
Cholesterol is the most basic steroid.
■ Major constituent of cell membranes and lipoproteins
steroid
Commonly present as a cholesterol ester
steroid
Conversion of HMG-CoA → mevalonate via HMG-CoA reductase is the RLS
precursor for other steroid mol.
Bile salts
■ Sex hormones
■ Adrenocortical hormones
■ Vitamin D
20-carbon long polyunsaturated fatty acids.
■ Derivatives of arachidonic acid
EICOSANOIDS
Phospholipase A2 (PLA2) releases arachidonic acid from plasma membrane
phospholipids upon hormone or cytokine stimulation or cellular
damage.
EICOSANOIDS
https://drive.google.com/open?id=0B8uJUY-tie8GS0RvUWVId3h1VDQ
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https://drive.google.com/open?id=0B8uJUY-tie8GbTBOTmNwYTExWk0
LIPOPROTEINS
Transport lipids in blood plasma.
■ Composed of a nonpolar lipid core surrounded by a single layer of amphipathic
phospholipids and cholesterol (see Figure 6–7).
LIPOPROTEINS
Characterized by the protein moiety embedded in their outer layer
(apoprotein)
LIPOPROTEINS
Contain triglycerides (16%), phospholipids (30%), cholesterol (14%), cholesterol
esters (36%), and free fatty acids (4%).
LIPOPROTEINS
Choline is essential for the secretion of lipoproteins from hepatocytes,
especially very low density lipoproteins (VLDL).
https://drive.google.com/open?id=0B8uJUY-tie8Gc1MzYlJvQjYwdVU
https://drive.google.com/open?id=0B8uJUY-tie8GVjRMYWdFTmpJYms
https://drive.google.com/open?id=0B8uJUY-tie8GUDRsQU1FSmNqWnM
https://drive.google.com/open?id=0B8uJUY-tie8GSU1YZWVyd3F1NDQ
bile salt
Aid in lipid absorption (emulsification and solubilization).
■ Absorption via micelles (water-soluble complexes).
■ Decrease surface tension of particles to break them into smaller sizes.
bile salt
Formed from cholesterol in the liver.
bile salt
Almost exclusively absorbed in the ileum and returned to the liver via the
enterohepatic (portal) circulation
bile salt
Those that are not reabsorbed are excreted.
■ Surplus bile salts are stored in the gall bladder
bile salt
Two major bile salts enter bile as glycine or taurine conjugates (occurs in
peroxisomes):
Glycocholic acid: Glycine + cholic acid.
■ Taurocholic acid: Taurine + cholic acid.
bile salt
lipid storage
Most lipid triglycerides are stored in adipose tissue
LIPID (LYSOSOMAL ) STORAGE DISEASES
Inherited disorders of the reticuloendothelial system.
■ Caused by incomplete lysosomal breakdown of sphingolipids and mucopolysaccharides
within phagocytes, leading to their accumulation
LIPID (LYSOSOMAL ) STORAGE DISEASES
Most are common to Ashkenazi Jewish ancestry.
https://drive.google.com/open?id=0B8uJUY-tie8GM2dRV2hMcWxTeUk
https://drive.google.com/open?id=0B8uJUY-tie8GWW1Kbll3emRQOVU
https://drive.google.com/open?id=0B8uJUY-tie8GUVIzX1VROXpRcFU
https://drive.google.com/open?id=0B8uJUY-tie8GRTBocl9nNWNEeDA
https://drive.google.com/open?id=0B8uJUY-tie8GWXI4ejBqLU9uRXc
https://drive.google.com/open?id=0B8uJUY-tie8GRTBocl9nNWNEeDA
https://drive.google.com/open?id=0B8uJUY-tie8GN2NQRzR4T3dYQ0U
https://drive.google.com/open?id=0B8uJUY-tie8GUGZEZmVTN0RDejQ
https://drive.google.com/open?id=0B8uJUY-tie8GdXgybUozWjg3bWc
https://drive.google.com/open?id=0B8uJUY-tie8GZXR2NFdxamFGdEU
Substrate-level phosphorylation:
■ Oxidative phosphorylation:
Substrate-level phosphorylation: ADP + Pi → ATP.
■ Oxidative phosphorylation: Major source of ATP (aerobic