Metabolism of Nucleoproteins , Nucleotides and Protein synthesis

1. A doctor administered Allopurinol to a 26-year-old young man with the symptoms of gout. What pharmacological action of Allopurinol ensures therapeutical effect?

A. *By inhibiting uric acid formation

B. By general analgetic effect

C. By increasing uric acid excretion

D. By general anti-inflammatory effect

E. By inhibiting leucocyte migration into the joint

2. In some regions of South Africa there is a spread sickle-shaped cell anemia, in which erythrocytes have shape od a sickle as a result of substitution of glutamine by valine in the hemoglobin molecule. What is the cause of this disease?

A. *Gene mutation

B. Disturbance of mechanisms of genetic information realization

C. Genomic mutations

D. Crossingover

E. Transduction

3. Nowadays about 50 minor bases have found in the t-RNA structure besides the main four nitrogenous bases. Choose the minor nitrogenous base:

A. *Dihydrouracil

B. Cysteine

C. Uracil

D. Adenine

E. Cytosine

4. RNA that contains AIDS virus penetrated into a leukocyte and by means of reverse transcriptase forced a cell to synthesize a viral DNA. This process is based upon:

A. *Reverse transcription

B. Convariant replication

C. Operon depression

D. Operon repression

E. Reverse translation

5. Methotrexate (structural analogue of the folic acid which is competitive inhibi­tor of the dihydrofolatreductase) is prescribed for treatment of the malignant tumour. On which level does methotrexate hinder synthesis of the nucleic acids?

A. Reparation

B. *Mononucleotide synthesis

C. Replication

D. Processing

E. Transcription

6. RNA-polymerase B (II) is blocked due to amanitin poisoning (poison of death-cup). What process is disturbed?:

A. Primer synthesis

B. Synthesis of t-RNA

C. Reverse transcription

D. *Synthesis of m-RNA

E. Maturation of m-RNA

7. An experiment proved that UV-radiated cells of patients with xeroderma pigmentosum restore the native DNA structure slower than cells of healthy individuals as a result of reparation enzyme defection. What enzyme helps this process?

A. DNA polymerase III

B. DNA gyrase

C. RNA ligase

D. *Endonuclease

E. Primase

8. A 42-year-old man suffering from gout has increased level of urinary acid in blood. Allopurinol was prescribed to decrease the level of urinary acid. Competitive inhibitor of what enzyme is allopurinol?

A. Adenosine deaminase

B. Hypoxanthine phosphoribosiltransferase

C. *Xanthine oxidase

D. Guanine deaminase

E. Adenine phosphoribosiltransferase

9. According to the model of double DNA helix that was suggested by Watson and Greek, it was astablished that one of chains would not be lost during replication and the second chain would be synthesized complementary to the first one. What way of replication is it?

A. Analogous

B. Dispersed

C. *Semicomservative

D. Identical

E. Conservative

10. 46-year-old patient complains of pain in joints that becomes stronger the day before the weather changes. Blood examination revealed an increased concentration of uric acid. This substance is accumulated in the blood o the patient due to intensive degradation of the following substance:

A. Cytidine monophosphate

B. Adenosine monophosphate*

C. Uridine triphosphate

D. Uridine monophosphate

E. Thymidine monophosphate

11. It was found out that some compounds for instance fungi toxins and some antibiotics can inhibit activity of RNA-polymerase II. What process will be disturbed in eukaryotic cell in a case of inhibition of this enzyme?

A. Transcription*

B. Reparation

C. Replication

D. Processing

E. Translation

12. On the ground of clinical presentations a patient was prescribed pyridoxal phosphate. This medication is recommended for correction of the following processes:

A. Synthesis of purine and pyrimidine bases

B. Oxidative decarboxylation of ketonic acids

C. Protein synthesis

D. Desammation of purine nucleootides

E. Transamination and decarboxylation of amino acids*

13.You are studying functioning of a bacteria operon. The operator gene has been released from the repressor. Immediately after this the following process will start in the sell:

A. Translation

B. Replication

C. Repression

D. Processing

E. Transcription*

14.An oncological patient was administered methotrexate. With the lapse of time the target cells of the tumour lost sensitivity to the preparation. We can observe changes in the gene expression of the following enzyme:

A. Dihydrofolate reductase*

B. Folate decarboxylase

C. Folate oxidase

D. Desaminase

E. Thiminase

15. Pterin derivatives (aminopterin and methotrexate) are the inhibitors of dihydrofolate reductase so that they inhibit the regeneration of tetrahydrofolic acid from dihydrofolate. These drugs inhibit the intermolecular transfer of monocarbon groups, thus suppressing the synthesis of following polymer:

1. Glycosaminoglycans
2. Homopolysaccharides
3. DNA *
4. Protein
5. Gangliosides

16. At the stage of translation in the rough endoplasmic reticulum, the ribosome moves along the mRNA. Amino acids are joined together by peptide bonds in a specific sequence, and thus polypeptide synthesis takes place. The sequence of amino acids in a polypeptide corresponds to the sequence of:

1. rRNA nucleotides
2. rRNA anticodons
3. mRNA codons *
4. tRNA nucleotides
5. tRNA anticodons

17. Infection diseases are treated with antibiotics (streptomycin, erythromycin, chloramphenicol). They inhibit the following stage of protein synthesis:

1. Translation *
2. Replication
3. Processing
4. Transcription
5. Splicing

18. Children with Lesch-Nyhan syndrome have a severe form of hyperuricemia accompanied by the formation of tophi, urate calculi in the urinary tracts, as well as serious neuro-psychiatric disorders. The cause of this disease is the reduced activity of the following enzyme:

1. Hypoxanthine guanine phosphoribosyl transferase *
2. Xanthine oxidase
3. Dihydrofolate reductase
4. Thymidylate synthase
5. Carbamoyl phosphate synthetase

19. A 46-year-old female patient consulted a doctor about pain in small joints of the upper and lower limbs. The joints are enlarged and shaped like thickened nodes. Serum test revealed an increase in urate concentration. This might be caused by a disorder in metabolism of:

Pyrimidines

Carbohydrates

Lipids

*Purines

Amino acids

20. A patient with hereditary hyperammonemia due to a disorder of Ornithine cycle has developed secondary orotaciduria. The increased synthesis of orotic acid is caused by an increase in the following metabolite of Ornithine cycle:

*Carbamoyl phosphate

Citrulline

Argininosuccinate

Urea

Ornithine

21. In cancer patients who have been continuously receiving methotrexate, the target cells of tumor with a time became insensitive to this drug. In this case, gene amplification of the following enzyme is observed:

*Dihydrofolate reductase

Thioredoxin reductase

Deaminase

AlAT

Thiaminase

22. During cell division, DNA replication occurs by a signal from the cytoplasm, and a certain pertion of the DNA helix unwinds and splits into two individual strains. What enzyme facilitates this process?

Restrictase

DNA polymerase

RNA polymerase

Ligase

*Helicase

23. A patient has decreased concentration of magnesium ions that are required for ribosomes connection to granular endoplasmic reticulum. This condition is known to disrupt the process of protein biosynthesis. Disruption occurs at the following state:

Translation*

Processing

Replication

Amino acid activation

Transcription

24. A 65-year-old man suffering from gout complains of pain in his kidneys. Ultrasonic examination revealed kidney stones. A certain substance in increased concentration can cause kidney stones formation. Name this substance:

Uric acid*

Urea

Cholesterol

Cystine

Bilirubin

Date: 2016-04-22; view: 2149