BioChem Intel Q Bank I

Question 1

A 46- year old man shows brownish- yellow pigmentation of the skin and a sclera, causing you to suspect hepatic jaundice if your diagnosis is correct, you might expect to see high levels of any of the following compounds except:

Answer 1

unconjugated bilirubin in the urine & LT

Question 2

Your patient presents with dark spots in his sclera black pigmentation of cartilage and collagenous tissue. His urine turns black while standing on air. You recognized these symptoms to be characteristics of:

Answer 2

Alkaptonuria & lt

This is because person has deficiency in homogentistic acid oxidase. The urine contains high levels of homogentisic acid, which is oxidized to a dark pigment while standing on air.

Question 3

In persons with phenylketonuria

Answer 3

Phenylalanine and Tyrosine are both essential amino acids

Question 4

Pheochromocytoma, a tumor of catecholamine-secreting cells causes dangerous hypertension in patients. These hypertensive episodes, you recommend as the best drug that one which inhibits:

Answer 4

Tyrosine hydroxylase

It converts tyrosine to DOPA. It inhibition was used in treatment of the above disease.

Question 5

In response to a B12 deficiency, which of the following conditions may develop in the patient if he is not treated?

Answer 5

Progressive Peripheral Neuropathy

Question 6

A young man with cirrhosis of the liver is not oriented to time and place. After he is placed in a low altitude. He experiences some improvements in mental status. Which of the following enzymes is partially responsible for these abnormalities in mental status?

Answer 6

Carbamoyal phosphate synthetase I

Question 7

Enzyme abnormalities can lead to hyperuricemia and gout include:

Answer 7

Reduced activity of hypoxanthine-guanine phosphoribosyltransferase

Question 8

You diagnose chronic granulomatosus disease in your patient. What is the most common primary cause of this disease?

Answer 8

Deficiency of NADPH oxidase

Question 9

Which of the following glycogen storage diseases results in cardiorespiratory failure leading to early death?

Answer 9

Pompe’s disease

Question 10

A type I diabetic has blood glucose of 250 mg/dl. After injection himself with insulin, the value decreased to 150 mg/dl. Which of the following changes in liver metabolism would most likely accompany this decrease?

Answer 10

Increased Hexokinase Activity

Question 11

Your patient is found to have hyperammonemia. Further studies lead to a diagnosis of ornithine transcarbamylase deficiency. Which of the following findings would be important in confirming that diagnosis?

Answer 11

Orotic Aciduria

Question 12

Which of the following processes reactions will be the slowest in a patient with uncontrolled diabetes mellitus.

Answer 12

Pyruvate dehydrogenase reaction

Question 13

Microcytic hypochromic anemia can result from all factors below.

Answer 13

Dietary deficiency of iron

Question 14

A study evaluating the relationship between folate levels and cardiovascular disease show that persons have twice the risk of cardiovascular disease mortality than those with higher folate levels. Which of the following enzymes is most closeley related to the role of folate in lowering the risk of:

Answer 14

Homocysteine methyltransferase

Question 15

When the insulin/glucagon ratio is high, which of the following enzyme activities is true?

Answer 15

Pyruvate kinase activity goes up and PEP carboxykinase decreases.

Question 16

A 10 month old child is being evaluated for the underlying causes of a hemolytic anemia. In the diagram shown below, the oxygen dissociation curve for hemoglobin in his erythrocytes is compared with the curve obtained with normal RBCs.

A deficiency of which enzyme is likely to account for the hemolytic anemia in this patient?

Answer 16

Pyruvate Kinase

Question 17

Analysis of the patient’s serum revealed an elevated VLDL. Which of the following mechanism accounts for the finding?

Answer 17

Decreased activity of lipoprotein lipase

Question 18

Mycophenolic acid is used to prevent graf rejection by depriving lymphocytes of nucleotides via:

Answer 18

Inhibition of IMP dehydrogenase

Question 19

A 14 year old girl has a history of diarrhea and fatty stools. Her serum cholesterol and triacylglycerol levels are extremely low. You recognize that her symptoms are likely to result from which of the following conditions?

Answer 19

Abetalipoproteinemia

Question 20

A 28 year old woman is seen for a routine examination. A blood smear reveals many large red blood cells and hypersemented neutrophils. Further analysis reveals a mild homocystinemia. Which of the following enzymes is most likely have abnormally low activity?

Answer 20

Cystationine Synthase

Question 21

A man with a history of genetic disease undergoes hip replacement surgery for arthritis. During the operation the surgeon notes a dark pigmentation in the man’s cartilage. His ochronotic arthritis is most likely caused by oxidation and polymerization of excess tissue.

Answer 21

Homogenistic acid

Question 22

Physical examination of a 21 year old mentally retarded man revealed hepatomegaly and splenomegaly. Bone marrow biopsy showed macrophages with :crumpled tissue paper” appearence of the cytoplasm. These symptoms are diagnostic of:

Answer 22

Gaucher’s Disease

Question 23

During bile salt metabolism in the intestine

Answer 23

Cholic acid is converted to deoxycholic acid

Question 24

If you suspect a deficiency of folate in the body of your patient, you know it can be diagnosed by high urinary excretion of:

Answer 24

Formiminoglutamate

Question 25

Acute intermittent porphyria is characterized by all of the following except

Answer 25

Cutaneous Photosensitivity

Question 26

In order to increase the reverse transport of cholesterol from peripheral tissues to the liver, you can recommend the drug that:

Answer 26

E. stimulates the expression of the ABCA1 protein

Question 27

In salvage reactions for purines

Answer 27

Purine nucleotides are formed from purines and phosphoribosyl phosphorylation

Question 28

The carbons of all amino acids end up in the TCA cycle. Which group of amino acids has common entry point to the cycle:

Answer 28

Arginine, Proline, glutamine

Question 29

A combination of elevated conjugated bilirubin, normal unconjugated bilirubin in the blood and absence of sterocobilin formation in a jaundiced patient suggests:

Answer 29

Bile duct obstruction

Question 30

A 2 - year old child is seen by her doctor and is noted to have mental retardation with enlarged liver and spleen. Bone marrow revealed the presence of numerous foam cells. This patient has:

Answer 30

Niemann-Pick Disease

Question 31

Analysis of blood plasma of your infant patient showed turbidity with elevated TG level. A plasma sample has been left in refrigerator overnight reveled cream colored material floating on top. The underlying plasma was clear. Which type of hyperlipoproteinemia is most likely present in this patient?

Answer 31

Type I

Question 32

In a glucose tolerance test, an individual is given to drink a large amount of glucose. If the individual is normal, this ingestion should result in which of the following?

Answer 32

An enhanced activity of Acetyl-CoA carboxylase

because this causes lipid synthesis induction

Question 33

Indicate which components contribute to the purine

Answer 33

Tetrahydrofolate contributes atom 7 of purine

Question 34

Which combination of amino acids if removed from the diet of an adult would result in negative nitrogen balance?

Answer 34

Phenylalanine, alanine, and serine

Question 35

You found elevated levels of phenylalanine and phenylpyruvate in the blood of a newborn infant. Which of the following enzymes you suppose to be deficient in this baby?

Answer 35

Dihydrobiopterin Reductase

Phenylalanine hydroxylase is dependent on this.

Question 36

If your patient reveals methylmalonic acidemia, you know immediately that a defect in his/her metabolism is caused by:

Answer 36

Deficiency of Cobalamin

Question 37

Heinz bodies are histological hallmark of what disorder?

Answer 37

Glucose-6-phosphate dehydrogenase deficiency

Question 38

Which of the following enzymes is believed to be most responsible for the development of cataracts in individuals with diabetes mellitus?

Answer 38

Aldose Reductase

which produces alot of sorbitol

Question 39

The failure of normal DNA synthesis in the lymphocytes of a patient with SCID is a result of inhibition of which of the following enzymes of purine nucleotide metabolism?

Answer 39

Ribonucleotide reductase

Question 40

Which of the following is characteristic of low insulin level?

Answer 40

Decreased activity of Lipoprotein lipase

Question 41

Diagnosis of adrenal pheocsynthesis of cholesterolhromocytomas is based on the urinary excretion of:

Answer 41

Vanillylmandelic acid derived from epinephrine

Question 42

A person whose sole protein source is corn may bedeficient in which amino acids?

Answer 42

Tryptophan and Lysine

Question 43

Cholestyramine exerts its hypocholesterolemic effect by interacting with:

Answer 43

Bile acids

Question 44

Markedly reduced levels of cholesteryl esters in blood lipoproteins results from a deficiency of:

Answer 44

Lecithin: cholesterol acyltransferase

Question 45

The circulating form of hemoglobin that is used to assess blood glucose concentration in diabetes mellitus is:

Answer 45

Hemoglobin A1

Question 46

Which of the following genetic disorders is due to a defect in lysosomal metabolism?

Answer 46

Hurler’s Disease

Question 47

Which of the following you expect to occur in a patient with an OXPHOS disease?

Answer 47

An increase in oxygen utilization

Question 48

Which of the following enzymes is regulated by reversible covalent modification?

Answer 48

Pyruvate dehydrogenase

Question 49

A person with insulin dependent diabetes mellitus failed to take insulin regularly and was found to have high VLDL and as a consequence, which of the following compounds in the blood would be elevated?

Answer 49

Triacyglycerols and cholesterol

Question 50

All of the following increase the extent of sickling in sickle cell anemia patients by increasing the proportion of deoxygenated hemoglobin S except

Answer 50

Increased ph

Increased carbon monoxide