Lab 9 - Lipids Flashcards
(36 cards)
Solubility of lipids
Insoluble in water, soluble in fat solvents
How does the lipids differ from each other, and what kind of groups of lipids do we have?
In chem. structure.
- Simple: esters of FA with glycerol. Gen. found in organisms as triacylglycerols. Saturated or unsaturated. Function: E storage.
- Derivated lipids - lipoids: Cholesterol is important. Phosphatides also.
How can simple esters be transferred in the organism?
By the blood circ. to the fat tissue to be stored as dipot fat, or transported from the dipot to the user organs in form of free FA.
Common unsaturated FA
Oleic acids. In plants high proportion of more unsaturated FA is common (linoleic, linolenic acids)
Where is cholesterol synthesized?
Liver
Function of cholesterol as lipid
- Precursor of steroid hormones and bile acids.
- Constituent of bio. membranes.
Function and example of phosphatides as lipids
- Membrane constituents
- E.g. Lecithin
How is long chain FA transported?
From fat depot to the user organs (muscle, liver) by the blood. Bound to albumin with sec.bonds.
How can a long chain FA be detached?
By Cu(II)sulphate/CuSO4 or Cu(II)nitrate/Cu(NO3)2 from the albumin. The produced copper salt can be dissolved in chloroform.
How does quantitative estimation of FFA work?
After detaching FA from albumin with Cu(II)-reagent:
The nr. of Cu2+ in the chloroform is the same nr. as FA, and can be measured by diethyldithiocarbamate by photometry.
Copper II reagent
Triethanol amine, acetic acid and copper sulphate solution
Materials in “quantitative estimation of FFA”
- Copper(II) reagent
- Na-diethyldithiocarbamate
- Chloroform
How is cholesterol transported in the organism?
Fro the site of synthesis (liver, intestinal wall, gonades) to user tissue while bound to albumin. Can be transported either in free or esterified form (by FA).
What is the principle method for measuring the totalt cholesterol conc. of the blood plasma?
- In presence of glacial acetic acid and sulphuric acid, FeCl3 will oxidize cholesterol and form new unsaturated double bonds.
- Two of these oxidized cholesterol molecules are able to bind to each other and prod. conjugated double bonds –> purple color.
- The intensity of the color can be measured with spectophotometry.
Materials in “measuring the cholesterol conc. of the blood”?
- Blood plasma
- FeCl3 solution: FeCl3 dissolved in glacial acetic acid
- Colour reagent: FeCl3 with conc. sulphuric acid
- Glacial acetic acid
Which diseases can be diagnosised with help from measuring cholesterol level?
- Hyperlipidaemia
- Some hepatic diseases (hepatopathies)
- Hyperadrenocorticism
- Hypothyreosis
Normal amount of total cholesterol in:
- dogs
- cats
- herbiivores
- dogs: 2,5-8 mmol/l
- cats: 2-6.5 mmol/l
- herbivores: 1,5-5 mmol/l
How are triglycerides transported?
In chylomicrons and diff. types of lipoproteins (VLDL, LDL, IDL, HDL) in the blood plasma.
Which enzymatic reactions is used to measure triglycerides conc. in blood plasma?
- Triglycerides transported in lioproteins are hydrolysed to glycerol and FA by lipoprotein lipase.
- Glycerol kinase enzyme converts glycerol to glycerol-3-P by using one ATP molecule.
- Glycerol-3-phosphate oxidase (GPO) oxidizes glycerol-3-P to dihydroxyacetonephosphate. At the same time H2O2 is released, by using O2 from air.
- The prod. H2O2 is converted to water by peroxidase enzyme (POD), while a red quinone derivate is prod.
Function of glycerol-3-phosphate oxidase (GPO)
Group of aerobe dehydrogenases. The prod. FADH2 passed the hydrogens directly to oxygen of the air, and H2O2 is released.
How can we measure the triglycerides conc. after the enzymatic reactions?
The red quinone derivate can be measured by spectrophotometry.
Materials in “measuring triglycerides conc. in blood”
- Blood plasma
- Colour reagent: enzymes and colour forming substrates (4-aminoantipyrine and phenol) dissolved in phosphate buffer.
- Standard triglyceride sol.
How is prim. bilde acids prod.?
During degradation of cholesterol in the liver.
Primary bile acids?
Cholic acid and chenodeoxycholic acid
