PHOSPHOLIPIDS, STEROIDS AND FAT-SOLUBLE VITAMINS

Question 1

occur in all biological membranes

Answer 1

Phospholipids

Question 2

They are amphipathic substances

Answer 2

Phospholipids

Question 3

Each phospholipid molecule contains a

Answer 3

polar head and a non-polar tail

Question 4

The molecular skeleton is made up of the residue

Answer 4

of glycerol or a more complex alcohol - sphingosine.

Question 5

A recurring structural element of all phospholipids containing glycerol - called
glycerophospholipids - is

Answer 5

phosphatidic acid

Question 6

One of the glycerophospholipids is ____, whose molecule, beside
glycerol, contains two chains of fatty acids, phosphate and choline.

Answer 6

phosphatidylcholine (lecithin)

Question 7

___ is the most abundant phospholipid in eukaryotic cells, it is also found in egg yolk

Answer 7

Lecithin

Question 8

It is easy to extract with a mixture of chloroform with methanol in a proportion of

Answer 8

2:1.

Question 9

Lecithin is difficult to dissolve in

Answer 9

anhydrous acetone

Question 10

Lecithin is not soluble in water, but thanks to the presence of the ____, it creates a persistent cloudy suspension in water

Answer 10

hydrophilic phosphocholine

group

Question 11

It is readily soluble in chloroform

Answer 11

lecithin

Question 12

During heating of lecithin, the ____ takes place.

Answer 12

dehydration of the glycerol molecule

Question 13

Unsaturated aldehyde forms - ____ - a substance with an unpleasant, pungent odour

Answer 13

acrolein

Question 14

It can be shown with one of the reducing tests, for example with chromate (VI). Acrolein reduces

Answer 14

potassium chromate (VI) (orange colour) to potassium chromate (IV) (green colour).

Question 15

In a highly alkaline reaction, the ____ takes place between choline and the phosphate residue of lecithin

Answer 15

hydrolysis of the ester bond

Question 16

The released choline decomposes to ____, which has a characteristic odour.

Answer 16

ethylene glycol and trimethylamine

Question 17

Alkaline hydrolysis releases fatty acids in the form of ___, which reduce the surface tension of water.

Answer 17

potassium salts (soaps)

Question 18

is released during alkaline hydrolysis

Answer 18

Phosphate contained in lecithin

Question 19

In reaction with ammonium molybdate (VI), it creates ammonium phosphomolybdate, which colours the solution

Answer 19

yellow

Question 20

Steroids are derivatives of

Answer 20

cyclopentaneperhydrophenanthrene

Question 21

The most common representatives of steroids are alcohols known as sterols, which have a hydroxyl group next to the C-3 carbon, among which __ is dominant.

Answer 21

cholesterol

Question 22

is a representative of animal sterols.

Answer 22

Cholesterol

Question 23

Due to the presence of a double bond, cholesterol creates ___ in the presence of
strong acids.

Answer 23

colourful products

Question 24

Under the influence of concentrated H2SO4 (Salkowski’s reaction), the ____
molecules takes place.

Answer 24

dissociation of water

Question 25

The most abundantly occurring bile acids are ____, in smaller quantities - lithocholic and chenodeoxycholic acids

Answer 25

cholic and deoxycholoic acids

Question 26

Bile acids are of an

Answer 26

amphipathic character

Question 27

The surface tension lowered by the bile acids present in the aqueous solution can be determined by the

Answer 27

settling at the bottom of the test tube of colloidal sulphur (sulphur flower) and the formation of a permanent suspension (emulsion) of oil in water.

Question 28

The main forms of vitamin D

Answer 28

ergocalciferol (vitamin D2) and cholecalciferol (vitamin D3).

Question 29

The A vitamins have an __. They are found exclusively in animal tissues in two forms: ____. Both are 20-carbon alcohols containing a six-member ring of beta-ionone with three methyl groups and a side chain containing two isoprene units.

Answer 29

isoprene structure ``` retinol 1 (vitamin A1) and retinol 2 (vitamin A2) ```

Question 30

lecithin solubility positive result

Answer 30

lecithin precipitate forms.

Question 31

Detection Of Glycerol - Acrolein Test

Answer 31

(+) Production of pungent smell | (-) Absence of pungent smell

Question 32

Detection Of Fatty Acids – Saponification Reaction

Answer 32

(+) Production of foam | (-) Absence of foam

Question 33

Detection Of Choline

Answer 33

observe the characteristic odour of the reaction product.

Question 34

Detection Of Phosphorus

Answer 34

(+) Production of yellow precipitate | (-) Absence of yellow precipitate

Question 35

Salkowski’s Reaction

Answer 35

chloroform-containing layer becomes red sulphuric acid layer fluoresces green.

Question 36

The Lieberman-Burchard’s Reaction

Answer 36

The liquid turns red, and then changes colour to blue and | finally green

Question 37

Detection of bile acids

Answer 37

Observe the formation of a red ring | on the border of the layers

Question 38

Lowering the surface tension by bile acids

Answer 38

Compare the sedimentation rate of sulphur.

Question 39

Detection of fat-soluble vitamins

Answer 39

After mixing, a blue colour starts to form proving the presence of vitamin A, which rapidly changes into purplish-red associated with the presence of vitamin D3

Question 40

are among the best-known components of living organisms. They are derived from organic acids, in which a hydrogen atom most often located near the α-carbon is substituted by the amino group. Some amino acids have two amino groups located at different carbon atoms, a few contain two or even three carboxyl groups. Two amino acids, proline and its hydroxylated derivative - hydroxyproline, have no amino group but an imino group, which is why they are called imino acids

Answer 40

Amino acids

Question 41

All amino acids, containing a free α-amino group, in a reaction with ninhydrine form products of a___ colour, while proline and hydroxyproline, containing the amino group, create ____-coloured products.

Answer 41

violet-blue yellow

Question 42

The aromatic rings of phenylalanine, tyrosine and tryptophan under the effect of nitric acid form ___-coloured nitro derivatives. This process is called the

Answer 42

yellow xanthoproteic reaction.

Question 43

Sulphur-containing amino acids:

Answer 43

cysteine and methionine

Question 44

Sulphur-containing amino acids:

Answer 44

cysteine and methionine

Question 45

Sulphur-containing amino acids:

Answer 45

cysteine and methionine

Question 46

The tryptophan indole ring reacts with glyoxylic acid in the presence of sulphuric acid (VI) to form a product of a

Answer 46

red-violet colour

Question 47

Proteins are constructed out of L-α-amino acids fixed with .

Answer 47

peptide bonds

Question 48

___ contain all the protein-building amino acids, others such as ___ (denatured collagen) do not contain cysteine and tryptophan, or contain only very smallundetectable in our conditions amounts of phenylalanine and tyrosine

Answer 48

albumin, egg protein gelatin

Question 49

The ___ has the characteristics of a double bond of the trans configuration

Answer 49

peptide bond

Question 50

The structure of peptide bonds resembles the binding occurring in a simple compound called a

Answer 50

biuret

Question 51

The structure of peptide bonds resembles the binding occurring in a simple compound called a

Answer 51

biuret

Question 52

The structure of peptide bonds resembles the binding occurring in a simple compound called a

Answer 52

biuret

Question 53

biuret reaction, characteristic for both:

Answer 53

peptides and proteins.

Question 54

is a commonly used colour reaction, used for the detection and quantification of peptides and proteins. It is characteristic of structures that have at least two peptide bonds

Answer 54

biuret reaction

Question 55

involves the destruction of its spatial structures while retaining the primary structure.

Answer 55

denaturation of protein

Question 56

Ninhydrin reaction - common to all amino acids

Answer 56

(+) Production of purple solution | (-) Absence of purple solution

Question 57

The Detection Of Aromatic Amino Acids - The Xanthoprotein Test

Answer 57

(+) Production of orange solution | (-) Absence of orange solution

Question 58

The Detection Of Sulphuric Amino Acids - The Cysteine Test

Answer 58

(+) Production of red-purple solution | (-) Absence of red-purple solution

Question 59

The Detection Of Tryptophan

Answer 59

Only in the test tube containing albumin, a reddish-purple ring will appear at the connection line of the layers, which indicates the presence of tryptophan

Question 60

Detection of the peptide bond - the biuret test

Answer 60

The fluid changes colour from blue to purple.

Question 61

Thermal denaturation of proteins

Answer 61

At first, precipitate forms, which then dissolves in excess of acetic acid.

Question 62

The action of concentrated nitric acid on protein

Answer 62

On the border of the | two liquids, a white-yellow layer of denaturised protein forms.

Question 63

The solubility of proteins is

Answer 63

highly variable

Question 64

Protein solutions are generally ___ with a monomolecular degree of dispersion

Answer 64

real solutions

Question 65

The protein solution then takes on the characteristics of the

Answer 65

colloidal solution

Question 66

Proteins exhibit

Answer 66

amphoteric properties.

Question 67

This characteristic of amino acids, peptides and proteins has been important in maintaining the ___ of tissues and body fluids

Answer 67

acid-alkaline balance

Question 68

an environment with a pH above the isoelectric point, proteins show a __ and can form compounds with cations of heavy metals

Answer 68

negative net charge

Question 69

In an environment with a pH lower than the isoelectric point, the resultant protein charge becomes ___.

Answer 69

positive

Question 70

Proteins can be separated from the low-molecule compounds in a process called

Answer 70

dialysis

Question 71

At sufficiently high concentrations of salt, protein can be completely precipitated from the solution. This phenomenon is called

Answer 71

salting out

Question 72

Test With Fe3+ Ion

Answer 72

(+) Production of yellow precipitate | (-) Absence of yellow precipitate

Question 74

Test With Pb 2+ Ion

Answer 74

(+) Production of white precipitate | (-) Absence of white precipitate

Question 75

Test With Hexacyanoferrate

Answer 75

A white precipitate forms.

Question 75

ESSBACH'S TEST

Answer 75

A yellow precipitate forms

Question 76

Test With Sulphosalicylic Acid

Answer 76

A white precipitate forms

Question 77

Test For The Presence Of Chloride

Answer 77

(+) Production of white precipitate | (-) Absence of white precipitate

Question 78

Test For The Presence Of Glucose

Answer 78

orange precipitate of copper oxide (Cu2O)

Question 79

Test For The Presence Of Protein - Biuret Test

Answer 79

(+) Production of deep purple solution | (-) Absence of deep purple solution