LIPIDS
1. Esterification of salicylic acid:
Write down the observations:
Write the esterification reaction of stearic acid by ethanol:
2. Extraction of lipids from hen egg yolk.
Write down (in points) the main steps of the extraction process.
Name basic components of hen egg yolk extract:
3. What are the products of lecithin alkaline hydrolysis ? Define the types of
chemical bonds between them. Mark hydrophilic and hydrophobic parts in the lecithin
formula below. Why is lecithin used as an emulgator?
LIPIDS 1
4. Unsaturated fatty acids. Detection of double bonds.
Give the substrate’s name. To which group of omega fatty acids does this fatty acid
belong?
KMnO4/Na2CO3
+ MnO2 ↓ brown precipitate
Di-hydroxy stearic acid
Explain the main differences between unsaturated fatty acids ω9, ω3, ω6. Name the fatty
acids below:
5. Qualitive analysis of cholesterol detection in natural products. Salkowski
reaction.
Why is the reaction’s product dyed (coloured)?
Why is Salkowski reaction positive with plant oil?
LIPIDS 2
6. Oxidation of the double bond in cholesterol. Windaus reaction.
Finish the reaction and name the product.
The product of reaction between cholesterol and fatty acids is ..............................
Mark the esterification place in the formula. What is the ester’s orientation towards
water environment?
What is the physiological concentration of total cholesterol in blood plasma?
7. and 8. Detection of bile acids.
Decrease in water surface tension by bile acids – Hay’s test with sulphur.
Name the acid below:
Mark in the formula which functional groups are responsible for water surface tension
decrease.
What does the mechanism of fat emulsification in the intestines consist in?
Pettenkofer’s reaction confirms the presence of ........................................ (finish the
sentence)
1. Bile acids form amides with glycine and taurine. Draw the formulae of taurocholic
acid (cholyltaurine) and glycocholic acid (cholylglycine). Define the type of bonds.
LIPIDS 3
Why do bile acids belong to a group of the best water-soluble steroids?
9. Name the compound.
What are the other biologically active forms of this vitamin?
In liver this vitamin is stored in the form of .....................................................
What is this vitamin’s significance for the organism?
Other tasks/questions:
1. To which group of lipid compounds does this chemical compound belong? Name it.
LIPIDS 4
2. Which of these compounds may be a part of cell membranes: triglycerides,
phosphatidylcholine, phosphatidylethanolamine, sphingomyelins, glycolipids,
cholesterol and its esters? Why? Why not?
3. Explain what oxidative stress means.
LIPIDS 5