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Multiple Choice Questions

Q.1-The major detoxification reactions involved in phase -1 are all except:

A. Oxidation

B. Reduction

C. Hydrolysis

D. Acetylation

E. Epoxidation

Q.2- The hydroxylated products of phase-1 are converted to soluble metabolites by coupling with polar agents in phase -2 of detoxification reactions by a process called Conjugation. Which of the following is not a conjugating agent?

A. Active acetate

B. Active sulfate

C. Active Methionine

D. Active Glucuronate

E. Active Bicarbonate.

Q.3- The biotransformation reactions are not only meant for removal of toxicity of foreign or endogenous compounds, under certain conditions the toxic potential of certain compounds is rather increased. The reactions involving increase in the toxicity of compounds are called “Entoxification reactions”. Which of the following is not an example of Entoxification reaction?

A. Conversion to Methanol to formate

B. Conversion to ethanol to acetate

C. Conversion of procarcinogens to ultimate carcinogens

D. Conversion of p-methyl amino Azo benzene to p-dimethyl amino Azo benzene.

E. Methylation of mercury

Q.4- Acetanilide is a constituent of analgesic drugs. It is detoxified to form p-Acetyl amino phenol. Which of the following processes is involved in this detoxification process?

A. Oxidation

B. Reduction

C. Hydrolysis

D. Acetylation

E. Methylation

Q.5- Digitalis a cardiac glycoside is detoxified forming a sugar and an aglycone by the process of-

A. Oxidation

B. Reduction

C. Hydrolysis

D. Acetylation

E. Methylation

Q.6- Phase -1 reactions are mainly catalyzed by a class of enzymes referred to as-

A. Mono- oxygenases

B. Mixed function oxidases

C. Cytochrome P 450 enzyme system

D. Al of the above.

E. None of the above

Q.7- Which of the following statements is incorrect about conjugation reactions?

A. Conjugation reactions can occur independently

B. The reactions can occur after phase -1 reaction

C. Most of the reactions take place in the liver

D. After conjugation most of the compounds are rendered non toxic

E. The polarity of the xenobiotics is decreased upon conjugation

Q.8- Which of the following compounds is detoxified by Glucuronidation reactions?

A. Aspirin

B. Methanol.

C. Bilirubin

D. Phenyl acetate

E. Bromobenzene

Q.9- Which of the following enzymes is involved in the Glucuronidation reactions?

A. UDP-G Pyro phosphorylase

B .UDP dehydrogenase

C. UDP Glucuronyl transferase

D. Glucan transferase

E. Glucuronidase

Q.10- Sulfation is an important method of detoxification of foreign compounds. Which of the following acts as a source of sulfate?

A. Sulphuric acid

B. Hydrogen sulphide

C. Phospho adenosine phospho sulfate

D. Methionine

E. Cysteine.

Q.11- The compounds conjugated by Methylation are all except:

A. Nicotinamide

B. Isoniazid

C. Oestrogen

D. Norepinephrine

E. Homocysteine

Q.12- Conjugation of foreign compounds with cysteine results in the formation of:

A. Hippuric acid

B. Mercapturic acid

C. Uric acid

D. Sulphuric acid

E. None of the above.

Q.13- The characteristic mousy odor of urine in a patient suffering from phenyl Ketonuria is due to the compound:

A. Phenyl acetyl glutamine

B. Phenyl Glucuronate

C. Phenyl lactate

D. Phenyl pyruvate

E. Phenyl Mercapturic acid

Q.14- The enzyme catalyzing the conjugation of glutathione with xenobiotics is:

A. Glutathione S-transferase

B. Glutathione peroxidase

C. Glutathione reductase

D. Glutathione synthase

E.  Glutathione Oxidase

Q.15- Which of the following reactions is used as an index for assessing the liver functions?

A. Formation of Hippuric acid

B. Methylation reactions

C. Acetylation reactions

D. Detoxification of ethanol

E. Glucuronidation reactions

Q.16- Which of the following is incorrect about Cytochrome P 450 enzyme system?

A. Most of these enzymes are inducible in nature

B. Some exhibit genetic polymorphisms

C. All of them are hemo proteins

D. They can be inhibited by drugs

E. They are Dioxygenases in their mechanism of action

Q.17- UDP-Glucuronic acid, the glucuronyl donor, in the Glucuronidation reactions is formed in the pathway of…

A. Glycolysis

B. Hexose mono phosphate

C. Uronic acid

D. Gluconeogenesis

E. Glycogenolysis

Q.18- Aspirin has antipyretic, analgesic and anti-atherogenic properties. It is detoxified by:

A. Oxidation

B. Reduction

C. Hydrolysis

D. Methylation

E. Glucuronidation

Q.19- The role of glutathione in tissues includes all except:

A. Participates in the decomposition of hydrogen peroxide

B. Biologically active in the oxidized form

C. Participates in the absorption of amino acids

D. Participates in the detoxification reactions

E. Participates in the activation of Methionine

Q.20- A 3 year old girl was brought into the Emergency Room. She was cold and clammy and was breathing rapidly. She was obviously confused and lethargic. Her mother indicated that she had accidentally ingested automobile antifreeze while playing in the garage. Following gastrointestinal lavage and activated charcoal administration, a nasogastric tube for ethanol was administered. How will ethanol help in relieving the symptoms?

A. Conjugate with methanol to form a soluble compound

B. Induce the alcohol dehydrogenase enzyme

C. Competitively inhibit the metabolism of methanol

D. Promote the excretion of metabolite of methanol

E. All of the above.


Key to answers

1)-D, 2)-E, 3)-B, 4)-A, 5)-C,6)-D,7)-E,8)-C,9)-C,10)-C,11)-B,12)-B,13)-A,14)-A,15)-A,16)-E,17)-C,18)-C,19)-B,20)-C.


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Q. 1- What is the normal physiological concentration of Hydrogen ion in body fluids?

A) 40 nEq/L

B) 24 mEq/L

C) 400 mEq/L

D) 7.4 nEq/L

E) 100 mEq/L

Q.2- Which of the following is not a source of hydrogen ion in the body?

A) Ingestion of Citrus fruits

B) High protein diet

C) Ingestion of red meat

D) Starvation

E) Chronic alcohol consumption

Q.3- Which of the following is the most important chemical buffer of the plasma?

A) HCO3 /H2 CO3

B) HPO42―/H2PO4

C) Organic Phosphate Esters

D) Proteins

E) Hemoglobin

Q.4- A primigravida in labor is breathing rapidly, what you expect out of the following

A) Metabolic Acidosis

B) Metabolic Alkalosis

C) Respiratory Acidosis

D) Respiratory Alkalosis

E) Any of the above.

Q.5- The Henderson-Hasselbalch equation is represented as-

A) pH = pK + log (A/HA)

B) pH = pK + log (HA/A)

C) pH = pK – log(A/HA)

D) pH = pK – log(HA/A)

E) pH = pK + log(H+/HA)

Q.6- Buffering effect of a buffering solution is optimum at :

A) pH ranges close to pKa± 2 pH units

B) pH = pKa ±3 pH units

C) pH = pKa ±5 pH units

D) pH = pKa

E) None of the above.

Q.7- The pH of extracellular fluid must be maintained between:

A) 6 to 7.4

B) 7 to 7.2

C) 7.35 to 7.45

D) 7.5 to 8

E) 8 to 8.5

Q.8- All are true for renal handling of acids in metabolic acidosis except

A) Hydrogen ion secretion is increased

B) Bicarbonate reabsorption is decreased

C) Urinary acidity is increased

D) Urinary ammonia is increased

E) Renal glutaminase activity is increased

Q.9- Which of the following is most appropriate for a female suffering from Insulin dependent diabetes mellitus with a pH of 7.2, HCO3-17 mmol/L and pCO2-20 mm Hg?

A) High anion gap metabolic Acidosis

B) Metabolic Alkalosis

C) Respiratory Acidosis

D) Respiratory Alkalosis

E) Normal anion gap metabolic acidosis

Q.10-A 50-year-old homeless man was brought to the emergency room in a stuporous state. Below are his lab results, Bicarbonate 10mEq/L (24-26), pH 7.2 (7.35-7.45), PCO2 25mmHg (35-45), Alcohol 40mmol/L (0), Osmolality 370mOsm/L (280-295), Glucose 50mg/dl (60-110) BUN 40mg/dl (5-22). What is the acid-base status?

A) Metabolic acidosis and metabolic alkalosis

B) Metabolic acidosis with partial respiratory compensation

C) Respiratory acidosis and partial metabolic compensation

D) Respiratory acidosis

E) Metabolic alkalosis

Q.11- A 44-year-old man is brought to the emergency room stuporous and obtunded. Serum chemistries are: HCO3 = 42 mEq/L; arterial pH = 7.5; PCO2 = 50mmHg. What is the acid-base status?

A) Metabolic acidosis and metabolic alkalosis

B) Metabolic acidosis with partial respiratory compensation

C) Respiratory acidosis and partial metabolic compensation

D) Respiratory acidosis

E) Metabolic alkalosis

Q.12-The medical student next to you, realizing that there is an examination question on acid base balance, begins nervously hyperventilating and then faints. You make him breathe into a paper bag and he recovers. If you had drawn and analyzed his blood when he fainted you would have expected to see :

A) Decreased pH, decreased pCO2

B) Decreased pH, elevated pCO2

C) Elevated pH, decreased pCO2

D) Elevated pH, elevated pCO2

E) Normal pH, normal pCO2

Q.13- All except one are examples of entoxification:

A) Conversion of methanol to formaldehyde

B) p- methyl amino benzene to p-dimethyl amino azo benzene

C) Conversion of procarcinogens to Ultimate carcinogens

D) Conversion of Aspirin to Acetic acid and Salicylic acid

E) Conversion of Ethyl alcohol to Acetaldehyde.

Q.14- In physiological jaundice of new-born, due to less availability of substrate and immature enzyme system, there is an impaired formation of soluble, non toxic form of bilirubin which is :

A) Bilirubin Sulphate

B) Bilirubin Phosphate

C) Bilirubin diglucuronate

D) Bilirubin Acetate

E) Methylated Bilirubin

15) In  phenylketonuria (a congenital disorder of phenylalanine metabolism that occurs due to deficiency of phenylalanine hydroxylase), there is impaired conversion of phenylalanine to tyrosine. The excess phenylalanine is detoxified and excreted in urine. Which of the following conjugating agents is used for detoxification of phenylalanine?

A) Glutathione

B) Glutamine

C) S-Adenosyl Methionine

D) Active Sulfate (PAPS)

E) D- Glucuronic acid

16) Which of the following is not a cause of secondary dehydration?

A) Excessive sweating

B) Comatose patient

C) Vomiting

D) Diarrhea

E) Congestive heart failure

17) The urinary concentration of sodium chloride (NaCl) ranges between:

A) 2-6 G/litre

B) 4-8 G/litre

C) 5-10 G/litre

D) 6-16 G/litre

E) None of the above

18) The minimum excretory volume to eliminate waste products from the body in dehydration is :

A) 100-200ml

B) 200-400 ml

C) 500-600 ml

D) 1500 ml

E) 600-800 ml

19) Aldosterone acts by promoting:

A) Excretion of Potassium

B) Reabsorption of potassium

C) Reabsorption of sodium

D) Excretion of sodium

E) Reabsorption of sodium and excretion of Potassium

20) Which of the following is not a cause of hypokalemia?

A) Renal tubular acidosis

B) Cushing syndrome

C) GI losses

D) Crush injuries

E) Insulin administration

Key to answers

1)- A, 2)- A, 3)-A, 4)-D, 5)-A, 6)-A, 7)-C, 8)-B, 9)-A, 10)- B, 11)-E, 12)-C, 13)-D, 14)-C, 15)-B, 16)-B, 17)-D, 18)-C, 19)-E, 20)-D.

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