Lesson 18 Module 1

Choose the type of infringement in pathology named alkaptonuria:

A. Genetic deficiency of enzyme*

B. The inhibition of amino acid formation

C. The renal insufficiency

D. The damage of receptor synthesis

E. The viral damage of hepatocyte

One of hereinafter stated compounds forms a connecting link between urea cycle and Krebs cycle via oxaloacetate. Point out it:

1. Alanine

2. Phenylalanine

3. Tryptophan

4. Aspartate*

5. Glutamate

Point out the pathological state that may be estimated in patients with genetic defect of Phenylalanine -4-hydroxylase:

A. Glucosemia

B. Hyperuricemia

C. Aminoaciduria*

D. Hypercholesterinemia

E. Dislipoproteinemia

Point out the cofactor required for the tyrosine formation from phenylalanine:

1. Coenzyme A

2. Tetrahydrobiopterin*

3. Coenzyme Q

4. Tetrahydrofolate

5. Lipoic acid

Which of the following compounds is not a catabolic product of tryptophan?

1. Kynurenine

2. Serotonin

3. Melanin *

4. Melatonin

5. Tryptamine

The child has the genetic defect of one enzyme. It was proved by the appearance of phenylpyruvate in the urine. Point out this enzyme:

A. Tyrosine hydroxylase

B. Phenylalanine 4-monooxygenase*

C. 5-tryptophan hydroxylase

D. Glycine amidase

E. Proline hydroxylase

Name an amino acid which is precursor in the synthesis of some hormones in human body:

1. Lysine

2. Alanine

3. Arginine

4. Serine

5. Tyrosine*

The major source of ammonia in the kidneys is:

1. Glutamate

2. Aspartate

3. Glutamine*

4. Histidine

5. Urea

Try to choose the index of blood plasma used for estimation of liver function in utilization of ammonia:

A. Pyruvic acid content

B. Urea content*

C. Uric acid concentration

D. Glucose concentration

E. Ketone bodies content

Which of the following statements is incorrect concerning synthesis of carbamoyl phosphate?

1. Mitochondrial carbamoyl phosphate synthase requires aspartate for its activity*

2. Two ATP may be consumed for its synthesis

3. This synthesis is catalyzed by carbamoyl phosphate synthase

4. It is the key reaction for urea formation

5. The nitrogen source can be either ammonia or glutamine

Cerebral trauma caused the increase of ammonia formation. What amino acid takes part in removal of ammonia from cerebral tissue?

1. Tryptophan

2. Lysine

3. Glutamic acid*

4. Valine

5. Туrosine

The amino acids required for the formation of glutathione are:

1. Glycine, cysteine, glutamate*

2. Serine, Tyrosine, tryptophan

3. Valine, leucine, isoleicine

4. Glutamate, aspartate, arginine

5. Cysteine, methionine, proline

Albinism is due to the lack of special enzyme in melanocytes. Name it:

1. Tyrosine decarboxylase

2. Tyrosinase*

3. Homogentisate oxydase

4. Kynureninase

5. Phenylalanine hydroxylase

Which one of the following amino acids may be converted to an intermediate metabolite of either the Krebs cycle or Urea cycle?

1. Tyrosine

2. Lysine

3. Leucine

4. Tryptophan

5. Aspartate*

Alkaptonuria is due to the deficiency of one enzyme in human tissues. Choose it

1. Tyrosinase

2. Phenylalanine hydroxylase

3. Dihydroxyphenylalanine (DOPA) decarboxylase

4. Homogentisate oxidase*

5. DOPA oxidase

Citrullinemia accompanied with vomiting, mental retardation, convulsions. Which urea cycle enzyme hereditary defect is a cause of mentioned disturbances?

1. Arginase

2. Arginosuccinase

3. Arginosuccinate synthase*

4. Carbamoyl phosphate synthase I

5. Ornithine transcarbamoylase

Point out the index of the blood plasma that may be used for the estimation of liver parenchyma damage:

A. Glucose

B. Urea

C. Free amino acids

D. Cholesterol ester

E. Ca²⁺

Point out the coenzyme used for hydroxylases structure in phenylalanine and tyrosine conversions:

A. Tetrahydrobiopterin*

B. Dihydrobiopterin

C. NADPH

D. FAD

E. Biotin

Which of the following functions is not specific for glutathione:

1. It serves as coenzyme for certain enzymes e.g. prostaglandine PGE₂ synthase

2. It prevents the oxidation of sulfhydryl groups of several proteins to disulfide groups

3. It serves as a storage and transport form of NH_3*

4. It protects a cell against cytotoxic H₂O₂ being coenzyme of glutathione peroxidase

5. It is involved in the transport of amino acids across cellular membrane in the intestine and kidney

Point out the pathology that is estimated in patients with genetic deficiency of dihydrobiopterin reductase:

A. Classic phenylketonuria

B. Gout

C. Phenylketonuria type II*

D. Diabetes mellitus

E. Ishemic heart disease

Find out the main important pathway for ammonia utilization in the brain:

A. Conversion into glucose

B. Urea formation

C. Amino acid decarboxylation

D. Synthesis of glutamine from alpha-ketoglutarate*

E. Ammonia salts formation

Choose the hormone that is formed from tryptophan:

A. Epinephrine

B. Thyroxin

C. Nor-epinephrine

D. Melatonin*

E. Histamine

Point out the enzyme whose deficiency causes the hyperammonemia state in patient:

A. Ornithine transcarbamoylase*

B. Arginine transaminase

C. Pyruvate dehydrogenase

D. Aspartate transaminase

E. L-Alanine oxidase

Which of the following statements is incorrect concerning synthesis of carbamoyl phosphate?

A It is mediated by different enzymes in the cytosol and mitochondria of the liver

B The nitrogen source can be either ammonia or glutamine

C It is the key reaction for urea formation

D This synthesis is catalyzed by ornithine transcarbamoylase*

E Two ATP may be consumed for its synthesis

N-acetylglutamate is activator for one enzyme involved in urea formation. Choose it:

1. Carbamoyl phosphate synthase I*

2. Ornithine transcarbamoylase

3. Argino-succinate synthase

4. Argino-succinase

5. Arginase

Nappies of a newborn have dark spots that witness the presence of homogentisic acid oxidation product. Choose the substance whose metabolic disorder is associated with accumulation of homogentisic acid in the organism:

1. Cholesterol

2. Galactose

3. Tyrosine*

4. Tryptophan

5. Methionine

A 4 y.o. boy has had recently serious viral hepatitis. Now there are such clinical symptoms as vomiting, unconsciousness, fits. There is hyperammoniemia in patient, too. Disturbance of which biochemical process caused such pathological condition of the patient?

1. Increased putrefaction of proteins in bowels

2. Inhibition of transamination enzymes

3. Disturbed neutralization of ammonia in the liver*

4. Activation of amino acid decaboxylation

5. Disturbed neutralization of biogenic amines

A 4 y.o. child with signs of durative proteinic starvation was admitted to the hospital. The signs were as follows: Growth inhibition, anemia, oedema, mental deficiency. Choose the cause of oedema development:

1. Reduced synthesis of lipoproteins

2. Reduced synthesis of glycoproteins

3. Reduced synthesis of hemoglobin

4. Reduced synthesis of globulins

5. Reduced synthesis of albumins*

Albinos can't stand sun impact – they don't require sun-tan but get sunburns. Disturbed metabolism of what amino acid underlies this phenomenon?

1. Histidine

2. Phenylalanine*

3. Tryptophan

4. Glutamic acid

5. Methionine

Maple syrup urine disease is due to a defect in the enzyme complex which catalyzes oxidative decarboxylation reaction and is similar to any other α-keto acid dehydrogenase complexes in composition. Some patients who exhibit the symptoms of this disease respond to therapeutic doses of hereinafter stated vitamins. Point out it:

1. Thiamine*

2. Pyridoxine

3. Biotin

4. Cobalamine

5. Ascorbic acid

After a serious viral infection a 3-year-old child has repeated vomiting, loss of consciousness, convulsions. Examination revealed hyperammoniemia. What may have caused changes of biochemical blood indexes of this child?

1. Activated processes of amino acids decarboxylation

2. The increased putrefaction of proteins in intestines

3. The inhibited activity of enzymes for transamination

4. Disorder of ammonia neutralization in ornithine cycle*

5. Disorder of biogenic amines neutralization

The brain ammonia isn’t neutralized through the formation of urea. Name the terminal product of ammonia neutralization in the brain:

A. Urea

B. Glutamine*

C. Carbamoyl phosphate

D. Aspartic acid

E. Alanine

Phenylketonuria is due to the absence of certain enzyme. Choose the reaction catalyzed by this enzyme:

1. Homogentisic acid oxidation

2. Phenylalanine hydroxylation*

3. Tyrosine deamination

4. Tyrosine iodination

5. Conversion of tyrosine to dihydroxyphenylalanine (DOPA)

Choose the blood plasma index that is used in screening of newborn for phenylketonuria estimation:

A. Phenylalanine*

B. Acetoacetate

C. Uric acid

D. Dihydroxyphenylalanine

E. Pyruvate

Point out the vitamin derivative that may be synthesized from tryptophan:

A. FAD

B. CoASH

C. FMN

D. NADH*

E. Carboxybiotin

A boy (of 10 years) complains of general weakness, dizziness, and tiredness. A mental retardation is observed. A concentration of valine, leucine, isoleucine is high in blood and urine. Urine has a specific odour. Name the probable diagnosis:

A. Basedow’s disease

B. Histidinemia

C. Maple syrup urine disease*

D. Addison’s disease

E. Tyrosinemia

Three biogenic amines are formed during the metabolism of tyrosine. Point out one of them:

A. Thiamine

B. Serotonin

C. Histamine

D. Thyroxin

E. Adrenalin*

A newborn child was found to have reduced intensity of sucking, frequent vomiting, hypotonia. Urine and blood exhibit increased concentration of citrulline. What metabolic process is disturbed?

A. Ornithinic (Urea) cycle*

B. Cori cycle

C. Glycolysis

D. Tricarboxylic acid cycle

E. Glyconeogenesis

Albinism is due to deficiency of the following enzyme:

1. Phenylalanine hydroxylase

2. Tyrosinase*

3. Homohentisic acid oxidase

4. Tyrosine decarboxylase

5. Tyrosine transaminase

Maple syrup urine disease is due to deficiency of:

1. Decarboxylase

2. Dehydroxylase

3. Transaminase

4. Deaminase

5. Alpha-keto acid dehydrogenase complex*

Xanthurenic acid is a product of metabolism of:

1. Tryptophan*

2. Glucuronic asid

3. Xanthine

4. Uric acid

5. Urea

If urine sample darkens on air standing, most likely diagnosis for patient is:

1. Phenylketonuria

2. Alkaptonuria*

3. Maple syrup urine desease

4. Diabetes mellitus

5. Albinism

Melanin may be synthesized from:

1. Tryptophan

2. Phenylalanine*

3. Cysteine

4. Methionine

5. Serine

The urine of patient with alkaptonuria contains:

A. Homogentisic acid*

B. Phenylalanine

C. Ketones

D. Acetates

E. None of the above

The most direct precursor of taurine is:

A. Glycine

B. Cysteine*

C. Methionine

D. Glutathione

E. Tyrosine

Urea is produced by single enzyme. Point out it:

A. Urease

B. Uricase

C. Arginase *

D. Glutaminase

E. Carbamoyl phosphate synthetase

Glycine is used for synthesis of:

A. Hemoglobin

B. Glutathione

C. Purine

D. Creatine

E. All the proposed options are correct*