Lipids Flashcards
A compound that can be dissolved in organic solvents but not with water
Lipids
Can lipids travel in the body on its own?
No
What is lipids composed mostly of?
Carbon-hydrogen bonds
Functions of lipids
Structural components of membranes
Storage and transport
Protective coating
Cell surface components
Metabolic fuel, building blocks of other lipids
Fatty acids
Fatty acid storage and transport of metabolic intermediates
Triglycerides
Membrane structure
Membrane signal transduction
Storage of arachidonic acid
Component of pulmonary surfactant
Phospholipids
For membrane structure
Sphingolipids
Metabolic fuel
Ketone bodies
Membrane component
Precursor for bile acids and steroid hormones
Cholesterol
Simplest lipid class in terms of structure
Fatty acids
2 major functions of fatty acids
Building blocks for triglycerides and phospholipids
Sources of metabolic energy
Fatty acid containing 4-6 carbons
Short chain
Fatty acid containing 8-12 carbons
Medium chain
Fatty acid containing >12 carbons
Long chain
Fatty acids that are straight chain compounds with even number of carbons
Dietary fatty acids
Fatty acid without double bonds
Medium to long chain carboxylic acids
Saturated FA
Fatty acid with double bonds (dehydrogenated)
Unsaturated FA
What makes the unsaturated FA more liquid at room temp?
Double bonds
It plays a role in decreasing lipid storage and lowering the tendency to block the blood flow in arteries
Double bonds
Two forms of FA
free fatty acid
Esterified fatty acid
Most metabolically active plasma lipid
Binds to albumin
Free fatty acid
Covalently linked with other molecules such as triglycerides, phospholipids, and cholesterol
Esterified fatty acid
Where is trans-fatty acid found?
Fried food
Commercially bakes goods
Processed food
Margarine
Has both hydrogen atoms located on the same side
Cis unsaturated FA
Has two hydrogen atoms on opposite sides
Trans unsaturated FA
Triple esters formed between glycerol and fatty acids
Triglycerides/triacylglycerols
Composition of triglycerides
1 glycerol
3 fatty acids
Functions of triglycerides
Part of the cell membrane
Storage form of lipids
Structurally similar to triglycerides
Derived from phosphatidic acid
Phospholipids/phospholycerides
Composition of phospholipids
1 glycerol
2 fatty acids
1 charged group (contain phosphate)
What is the nature of phospholipids
Amphipathic
This part of the phospholipid interacts with water
Polar head
This part of the phospholipid interacts with organic compounds
Non-polar tail
Phosphatidyl cholin
Lecithin
Phosphatidyl ethanolamine
Cephalin
Diphosphatidyl glycerol
Cardiolipin
Lung surfactant composition
Lecithin and sphingmyelin
What is the purpose of lecithin and sphingomyelin in the lungs?
It voids the collapse of pneumocytes
one of the methods used to assess fetal lung maturation
Lecithin-sphingomyelin ratio
If the LS is low, what will happen to the newborn?
Die
Unsaturated steroid alcohol of high molecular weight
Cholesterol
This form of the cholesterol contains one FA molecule
Esterified cholesterol
Functions of cholesterol
Manufacture and repair cell membranes
Synthesis of bile acids and vitamin D
Precursor of 5 major classes of steroid hormones
What are the 5 major classes of steroid hormones?
Progestin
Androgens
Glucocorticoid
Estrogen
Mineralocorticoids
Waxy material which form a plate-like crystals
Plays an important role in plaque formation in the blood vessels
Cholesterol
Recommended cholesterol intake of adults per day
<300 mg/day
Normal range for cholesterol intake for adults
100-700 mg/day
How much cholesterol is being produced in the liver and other tissues?
500-1000 mg
How much biliary cholesterol is secreted into the intestine daily?
600-1000 mg
Types of cholesterol
Free cholesterol
Esterified cholesterol
Sugar containing lipid that consists of a sphingosine (backbone) molecule that has a fatty acid attached to its amino group and a sugar linked to the primary alcohol group (ceramide)
Glycolipids/sphingolipids
Sugar component of lipids
Sphingolipids
Simplest glycolipids
Cerebrosides/galactosylceramide
What will the galactosylceramide produce?
Glucosylceramide
Major lipids of cell membranes of the brain and CNS
Gangliosides
Plays an important role in cell recognition and blood typing
Glycosphingolipids
Where is glycosphingolipids stored?
On the RBC membrane
Protein associated with plasma lipoproteins
Apolipoproteins
Structural elements in the amphipathic shell of lipoprotein particles and help to keep lipids in solution during circulation through the blood stream
Apolipoproteins
Regulate plasma lipid metabolism by activating and inhibiting enzymes that are involved in the process
Apolipoproteins
Interact with specific cell-surface receptors and direct the lipids to the correct target organs and tissues in the body
Apolipoproteins
Who discovered the apolipoprotein?
Peter alaupovic
Apolipoprotein that is a major component of HDL
Apo A
Major activator of LCAT
Apo A-I
Activates hepatic lipase
Apo A-II
Cofactor of LCAT
Apo A-IV
Major protein component of LDL
Apo B
Binds to LDL cell receptor
Apo B100
Structural role in chylomicrons
Apo B-48
Major protein component of VLDL
Apo C
Also activates LCAT
Apo C-I
Potent activator of LPL
Apo C-II
Regulates rate of clearance of TAG-rich lipoprotein (inhibit LPL)
Apo C-III
Apo A-III; serves as lysolecithin carrier
Apo D
Recognizes cell receptors to target chylomicrons and VLDL remnants to the hepatic receptors
Apo E
Carrier proteins; carries triglycerides and cholesterol to the different parts of the body
Lipoproteins
Body’s petroleum industry
Lipoproteins
Component of the outside of lipids
Cholesterol and triglycerides
Components of the core of lipoproteins
Apolipoproteins, phospholipids, free cholesterol
Largest of the lipoproteins particles
Major carrier of exogenous triglycerides
Chylomicrons
End stage of chylomicrons
Liver
Clearance time from the formation of CM after a meal and the removal of the remnants
6 hours
Indicative of presence of CM and signals a defect in their clearance
Creamy layer rising to the top of a fasting serum that has been cooled overnight
Carry triglycerides assembled in the liver out to the cells (endogenous)
VLDL
Synthesized in the liver and are responsible for transporting cholesterol from the liver to the peripheral tissues
LDL
Bad cholesterol
LDL
Smaller denser ldl IS ASSOCIATED WITH WHAT?
Higher risk of chd
Very small ldl is associated with what?
Triglyceride and pancreatitis
Gather up extra cholesterol from the tissues for transport back to the liver
HDL
Good cholesterol
HDL
indicates obstructive biliary disease
elevated LPX
floating beta lipoprotein
richer in cholesterol than vldl
serious risk for atherosclerosis
beta vldl
large hdl rich in cholesterol
contains apo e
seen when diet is very high in cholesterol
HDLc
patient should have a regular diet for how long prior to the blood collection
3 weeks
there should be no alcohol consumption for how many days prior
2 days
sample should be collected after a fasting of how many years
12 hours
triglyceride determination methods
zilversmith and van handel
enzymatic method
end product of zilversmith and van handel
formaldehyde (pink color)
bloor’s reagent components
alcohol and ether
steps in zilversmith and van handel
- extract using organic solvents (bloor’s reagent)
- add KOH for the hydrolysis of triglyceride into fatty acid
- (measurement of glycerol) oxidize glycerol by periodate solution to formaldehyde
- color reaction of formaldehyde (formaldehyde + chromotrophic acid)
easy to use, more rapid, low-cost, and efficient
uses lipase- no extraction needed
enzymatic method
colored product of enzymatic method for triglyceride determination
pyruvate kinase
fluorometry of plasma triglyceride determination
hantzsch method
colored product of plasma triglyceride determination
yellow (400-485nm)
where do adults belong in the classification of TAG values
ATPIII
triglyceride- <150 mg/dL
normal
triglyceride- 150-199 mg/dl
borderline high
triglyceride 200-499 mg/dl
high
triglyceride => 500 mg/dl
very high
