Complex Lipids Flashcards
constitute the main components of membranes.
Complex lipids
Complex lipids can be classified into two groups:
phospholipids and glycolipids
contain an alcohol, two fatty acids, and a phosphate group.
Phospholipids
There are two types of phospholipids:
glycerophospholipids and sphingolipids
the alcohol is glycerol.
glycerophospholipids
the alcohol is sphingosine.
sphingolipids
are complex lipids that contain carbohydrates.
Glycolipids
In this glycerol is the alcohol group.
Glycerophosphatides
In this group, inositol is the alco-hol, e.g. phosphatidyl inositol (lipositol).
Phosphoinositides
Alcohol present is sphingosine (also called as sphingol), an unsaturated amino alcohol. e. g. sphingomyelin.
Phosphosphingosides
GLYCEROPHOSPHOLIPIDS also called
phosphoglycerides
contains a glycerol core with fatty acids. They can be the same or different subunits of fatty acids.
Glycerophospholipids
(tail, apolar) contains a fatty acid. typically saturated
Carbon 1
contains a fatty acid, typically unsaturated and in the cis conformation, thus appeamng, “bent”
Carbon 2
contains a phosphate group or an alcohol attached to a phosphate group
Carbon 3
the alcohol inositol is bonded to the rest of the molecute by a phosphate ester bond.
phosphatidylinositols (PI)
• has stearic acid on one end and linoleic acid in the middle
• used commercially in foods requiring a natural emulsifier and/or lubricant, and in pharmaceuticals as protective coverings
Lecithin
• a lipid found in biological membranes
• found particularly in nervous tissue such as the white matter of brain, nerves, neural tissue, and in spinal cord
• principal phospholipid in bacteria
Cephalin
• negatively charged phospholipid
• minor component in the cytosolic side of eukaryotic cell membranes
• play important roles in lipid signaling, cell signaling and membrane trafficking
Phosphatidyl inositol
• usually kept on the inner leaflet, the cytosolic side, of cell membranes by an enzyme called flippase
Phosphatidyl serine
an important component of the inner mitochondrial membrane
Cardiolipin
a rare genetic disorder that was recognized in the 1970s to Infantile death
Barth syndrome
It’s reported that CL content in the brain would decrease with aging
Parkinson’s disease and Alzheimer’s disease
decreased CL levels and change in acyl chain composition are also observed in the mitochondrial dysfunction
Nonalcoholic fatty liver disease and heart failure
mainly caused by abnormal enhanced production of CL
Tangier disease
has recently been found to be deficient in the heart at the earliest stages of diabetes, possibly due to a lipid-digesting enzyme that becomes more active in diabetic heart muscle
Diabetes
with anti-cardiolipin antibodies can have recurrent thrombotic ayents even early in their mid to late teen years
Antiphospholipid syndrome
Cardiolipin from a cow heart is used as an antigen in the Wassermann test for?
Syphilis
it is found that two antibodies directed againat 2F5, 410 in membrane-proximaliregion, MPR, react with self-antigons, including cardiolipin
HIV-1
it is suggested that abnormalities in CL can impair mitochondnal function and bicenergetics.
Cancer
Phospholipids participate in the lipoprotein complexes which are thought to constitute the matrix of cell walls and membranes, the myelin sheath, and of such structures as mitochondria and microsomes.
Structural
Certain enzymes require tightly bound phospholipids for their actions, e.g. mitochondrial enzyme system involved in oxidative phosphorylation.
Role in enzyme action
Phospholipids play an essential part in the blood coagulation process.
Role in blood coagulation
Platelets provide the chief source of PL and that part of total lipid content of the platelets which contribute to intrinsic blood coagulation process is called
platelet factor 3
Lecithin lowers the surface tension of water and aids in emulsification of lipid water mixtures, a prerequisite in digestion and absorption of lipids from GI tract.
Role in lipid absorption in intestine
Exogenous TG is carried as lipoprotein complex, chylomicrons, in which PL takes an active part.
Role in transport of lipids from intestines
Endogenous TG is carried from Liver to various tissues as lipoprotein complex Pre-ß-lipoprotein (VLDL), PL is required for the formation of the lipoprotein complex.
Role in transport of lipids from liver
Probably PL help to couple oxidation with phosphorylation and maintain electron transport enzymes in active conformation and proper relative positions.
Role in electron transport
Choline acts as a lipotropic agent as it can prevent formation of fatty liver. As lecithin can provide choline it acts as a lipotropic agent.
Lipotropic action of lecithin
Phospholipids are in some way implicated in the mechanism of secretion is suggested by the observation that phaspholipids, specially phosphatidic acid and phosphoinositides turnover is proportional to the rate of secretion of cells liberating such products as hormones, enzymes, mucins and other proteins.
lon transport and secretion
Phospholipids of myelin sheaths provide the insulation around the nerve fibres.
Insulation
Phospholipids are required as a cofactor for the activity of the enzyme lipoprotein lipase and triacyialycerol lipase.
Cofactor
Myelin, the coating of nerve axons. contains a different kind of complex lipid
sphingolipids
The combination of a fatty acid and sphingosine is called the
ceramide
are complex lipids that contain carbohydrates and ceramides.
Glycolipids
consists of ceramide mono- of oligosaccharides.
cerebrosides
contain a more complex carbohydrate structure.
gangliosides
- The third major class of lipids
- In this structure, three cyclohexane rings (A, B. and C) are connected in the same way as in phenanthrene; a fused. cyclopentane ring (DI is also present.
Steroids
The most abundant and the most important steroid in the human body.
Cholesterol
is almost pure cholesterol
human gallstone
spherically shaped clusters containing both lipid molecules and protein molecules,
Lipoproteins
which consists of about 33% protein and about 30% cholesterol
High-density lipoprotein (HDL) (“good cholestero”)
which contains only 25% protein but 50% cholesterol
Low-density lipoprotein (LDL) (“bad cholesterol”)
which mostly carres triglycerides (fats) synthesized by the liver
Very-low-density lipoprotein (VLDL)
which carry dietary lipids synthesized in the intestines
Chylomicrons
The LDL carries cholesterol to the cells, where specific LDL- receptor molecules line the cell surface in certain concentrated areas called
coated pits
• the cholesterol level in the plasma - 680 mg/100 ml
• Normal 175 mg/
Familial hypercholesterolemia
a term that includes the total level of cholesterol that is found in the bloodstream
Serum cholesterol
known as P4 (pregn-4-ene-3,20-dione) is a C-21 steroid hormone
Progesterone
Progesterone sometimes called?
Hormone of pregnancy
are products of the adrenal glands
adrenocorticoid hormones
one of the most important mineratocorticoids.
Aldosterone
Its function is to increase the glucose and his centalior occurs at the body.
cortisol
cortisol usually referred to be?
Stress hormone
counteracts Insulin, contributing to hyperelvcemia
Insulin
in rats, toss of collagen from skin
Collagen
stimutates gastric acid socretion:
Gastmc secretion
inhibit: loss of sodlum from small intestines of mammais
Sodium
causes alkalosis of the serum
Potassium
acts as an anti diuretic hormone
Water
increasing copper availability fon immune purposes
Copper
