Examples of Krok 1 tests

61. Out of 200 different amino acids form in nature the number of amino acids present in protein:

A. 20

B. 25

C. 40

D. 35

E. 100

62. Choose from listed below methods ONE, which is used for fractionation of protein mixtures and isolation of individual proteins (enzyme, hormone, toxin etc):

1. Affinity chromatography

2. Precipitation with nitric acid

3. Boiling of extracts

4. Proteolysis

5. Radioimmunoassay

63. Determination of C-reactive protein (CRP) in blood plasma is conducted with the use of antisera, containing specific antibodies against CRP. What type of analytical method is used in this case?

Immunoprecipitation

1. Spectrophotomenry

2. Electrophoresis

3. Chromatography

4. Polarography

64. Proteins are biopolymers of principal significance in cell building, they are composed from amino acids as monomers, which are connected into chain by the next main type of chemical bond:

1. Peptide bond

2. Phosphodiester bond

3. Ionic bond

4. Hydrogen bond

5. Glycosidic bond

65. Protein preparations from human blood plasma are frequently used in clinical medicine for treatment of many diseases. Fractionation of blood plasma and preparation of distinct protein fractions is achieved by the next method:

1. Fractional precipitation with ammonium sulfate

2. Fractional precipitation with ethanol by Cohn VI method

3. Precipitation with salts of heavy metals

4. Electrophoresis in agarose gel

5. Ultracentrifugation

66. Determination of proportion between protein fractions in blood plasma or serum has an important clinical and diagnostic significance. The following routine method for obtaining results of this sort is most frequently used in clinical laboratories:

1. Salting out with neutral salts

2. Absorption chromatography

3. Precipitation with strong acids

4. Electrophoresis in agar gel or on acetyl-cellulose films

5. Immunoprecipitation

67. For determination of DNA synthesis in the cell usually is used measurement of incorporation of H³-thymidine into cellular biopolymers. The next type of analysis is used in this specific case:

1. Radioisotope method

2. Polymerase chain reaction (PCR)

3. Electrophoresis

4. Radioimmunoassay

5. Affinity chromatography

68. Proteins are biopolymers of principal significance in cell building, they are composed from amino acids as monomers, which are connected into chain by the next main type of chemical bond:

1. Peptide bond

2. Phosphodiester bond

3. Ionic bond

4. Hydrogen bond

5. Glycosidic bond

Clinical cases and Situational tasks

69. A protein solution was heated to 50⁰C and lost all its properties. How can this be explained?

ANSWER: During heating there was denaturizing of protein.

70. With the use of salting out protein was separated from the biological solution. This protein will be used for treatment. What needs to be done to separate the protein from other molecular additives?

ANSWER: The separation of protein from the other molecular additives can happen with dialysis or gel-filtration

71. The total amount of protein in human blood is 50g/L. What can you conclude from this information, and what can cause this state?

ANSWER: If the total amount of protein in blood is 50g/L, this means that that person has hypoproteinemia. This state can be observed during the deficit of proteins in food, starvation, cachexia, stop of synthesis of proteins in the liver and in other states as well.

72. During analysis of urine, a positive reaction with Sulfosalicylic acid was observed. In total, 0.253% of protein was observed. What does this signify? What effects can this condition have on the organism?

ANSWER: If during analysis of urine, a positive reaction with Sulfosalicylic acid was observed, then this means that there is protein present in the urine. This occurs during cachexia, infectious sickness, nephritis, and so on. This condition can lead to hypoproteinemia, lowering of oncotic pressure and signs of inflammation.

73. The total amount of protein in blood of the patient is 95g/L. Is this normal? What is the cause of this state?

ANSWER: If the total amount of protein in human blood is 95g/L, then the condition observed is known as hyperproteinemia. This is observed during water loss by the organism, hepatitis, chronic inflammatory states, collagenosis, lymphma, endotheliomas and so on.

74. Name compartments of an animal cell:

Answer:

75. Discribe the method, shown at the picture below:

Answer: Dialysis is a passage of solutes through a semi-permeable membrane (cellulose tube). Molecules smaller than the pore size pass through the membrane (water, salts, protein fragments); protein stays in the tube.

76. Discribe the method, shown at the picture below:

Answer: Size exclusion chromatography (gel filtration chromatography) - separation based upon molecular size. Column is filled with semi-solid beads of a polymeric gel that will admit ions and small molecules into their interior but not large ones. When a mixture of molecules and ions dissolved in a solvent is applied to the top of the column, the smaller molecules (and ions) are distributed through a larger volume of solvent than is available to the large molecules. Consequently, the large molecules move more rapidly through the column, and in this way the mixture can be separated (fractionated) into its components. The porosity of the gel can be adjusted to exclude all molecules above a certain size. Sephadex, Sepharose or Sephacryl, which are fine porous beads, are trade names for gels that are available commercially in a broad range of porosities on the basis of their density and sedimentation velocity