Lipids & Lipoprotein Metab Disorders Flashcards
What are Lipids ?
compounds that are soluble in organic solvent but neatly insoluble in water
Classification of Clinically Important Lipid
1) Sterol Derivatives
2) Fatty Acids
3) Glycerol Esters
4) Sphingosine Derivatives
5) Terpenes
Non lipid groups that can be contained in some lipids
1) Sialic
2) phosphoryl
3) amino
4) sulphate groups
function of non lipid groups in lipids
they give lipid molecules an affinity for both water & organic solvents which is important in the formation of biological membranes
function of non lipid groups in lipids
they give lipid molecules an affinity for both water & organic solvents which is important in the formation of biological membranes
sterol derivatives
- cholesterol & its esters
- steroid hormones
- bile acids
- vit. D
fatty acids
- short chain (2-4 carbon atoms)
- medium chain (6-10 carbon atoms)
- long chain (12 - 26 carbon atoms)
Terpenes
Vit A, Vit E, vit K
the only hydrophilic part of cholesterol is
the Hydroxyl group in the A-ring
*makes cholesterol an Amphiphatic Lipid
esterified form of cholesterol
cholesteryl ester
cholesterol esters do Not contain polar groups, T or F
True
*it makes them completely hydrophobic
cholesterol can be converted in the liver to _ & _ acids
cholic acid & chenodeoxycholic acid
fate of cholesterol
1) liver converts to primary bile acids
2) adrenal glands, testes & ovaries convert to steroid hormones
3) can be transformed to Vit D3 in skin after being converted to 7-dehydrocholesterol
what are fatty acids
linear chains of carbon-hydrogen bonds that terminate with a carbonyl group (COOH)
Fatty acid chain lengths
1) short chain ( 2-4 carbon atoms)
2) medium chain ( 6-10 carbon atoms)
3) long chain (12-16 carbon atoms)
FA chains important to metabolism & nutrition inhumans aare of which class
long chain
classify FA according to degree of saturation
1) Saturated FA
2) Monounsaturated FA
3) Polyunsaturated FA
*double bonds in polyunsaturated FA are usually 3 carbon atoms apart
which FA is found in only plants ?
Linoleic acid
_ FA is not synthesized but is vital for health, growth & devpt
Essential FA
most free FA is bound to _
Albumin
clinical importance of FA
1) faecal FA used to determine malabsorptive & pancreatic disorders
2) free FA distinguish between HYPERINSULINEMIC HYPOGLYCEMIA (FFA normal) and disorders of FA oxidation (FFA elevated)
what is glycerol?
glycerol is a three carbon atoms alcohol that contains a hydroxyl group on each of its carbon atoms
*each hydroxyl group can be esterified with a fatty acid
the class of acylglycerol is determined by _
the number of fatty acyl groups present
diff between phosphoglycerides & triglycerides
they have only two esterified Fatty Acids
3rd position on the glycerol back bone contains an “A” group (hydrogen atom) making it a
Diacylphosphoglycerine
if A group is a choline then the molecule is referred to as ..
PhosphatidylCholine
triglycerides are removed from chylomicrons by the action of what enzyme
Lipoprotein Lipase
apoproteins in chylomicrons
apo B48, apoC-1, C11, C-111 & apo-4
principle role of chylomicrons
delivery of dietary lipids to the hepatic & peripheral cells
very low density lipoprotein is synthesized where ?
the Liver (from carbohydrate, saturated FA & transFA)
chylomicrons are rich in __ TG while VLDL are rich in __ TG
exogenous
endogenous
apolipoproteins in VLDL
ApoB-100, ApoC111, Apo E
Low Density Lipoproteins primarily contain apo_
B100
macrophages that take up too much lipid become
foam cells
Friedewald equation
LDL-c (mg/dl) = TC - CHDL-c + VDL-c
VDL-c = TG/5
HDL is synthesized by _ & _
liver & intestine
what apolipoprotein is contained in HDL
apo A1
what is lipoprotein(a)
These are LDL-like particles that contain one molecule of apo(a) linked to apoB-100 by a disulfide bond
what is lipoprotein(a)
These are LDL-like particles that contain one molecule of apo(a) linked to apoB-100 by a disulfide bond
what is the temperature & time for fridge test ?
& what is the test based on ?
40degrees for 18 hrs
*that chylomicrons being less dense than serum will float to the top giving a creamy supernatant layer
Examples of the support medium in Electrophoresis ?
Agarose or Cellular acetate
what bands appear in plasma after electrophoresis ?
alpha band - HDL
beta band - LDL
pre-beta band - VLDL
*chylomicrons don’t exist in plasma so remain at the application line.
what is contained in a lipid profile ?
Total Cholesterol
Total Triglyceride
HDL Cholesterol
LDL cholesterol
VLDL Cholesterol
AIP = Log [TG]/[HDL]
preanalytical factors that influence cholesterol results
1) Age
2) sex
3) Fasting
4) Stress
5) Time of Specimen
6) Haemolysis
