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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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