MEDICINAL CHEMISTRY MCQ AND NPC EXAM DAILY SERIES 31

NPC EXAM DAILY MCQ SERIES

[Medicinal chemistry]                   

                                                                         

1. Which one of the followings is a plasminogen activator? 

(A) Tranexamic acid 

(B) Streptokinase

(C) Aminocaproic acid 

(D) None of the above 

2. Myasthenia gravis is diagnosed with improved neuromuscular function by 

using:

(A) Donepezil

(B) Edrophonium 

(C) Atropine 

(D) Pancuronium

3. Which one of the following drugs specifically inhibits calcineurin in the

activated T lymphocytes?

(A) Daclizumab 

(B) Prednisone

(C) Sirolimus 

(D) Tacrolimus

4. The chemical behaviour of morphine alkaloid is: 

(A) acidic 

(B)Basic 

(C) neutral 

(D) amphoteric

5. At physiological pH the following compound would be mostly in the:

(A) cationic form 

(B) unionized form 

(C) zwitterionic form 

(D) anionic form

6. Which one of the followings is used as a mood stabilizer for bipolar disorder and also in certain epileptic convulsions? 

(A) Phenytoin 

(B) Lithium 

(C) Sodium valproate 

(D) Fluoxetine

7. An isosteric replacement for carboxylic acid group is: 

(A) pyrrole 

(B) isoxazole

(C) phenol 

(D) tetrazole

8.The given antibiotic is an example of ansamycins : 

(A) Roxythromycin 

(B) Adriamycin

(C) Aureomycin 

(D) Rifamycin

9.  For glyburide, all of the following metabolic reactions are logical except:

(A) O-demethylation 

(B) aromatic oxidation

(C) benzylic hydroxylation 

(D) amide hydrolysis 

10.  The effects observed following systemic administration of levodopa in the treatment of Parkinsonism have been attributed to its catabolism to dopamine. Carbidopa, can markedly increase the proportion of levodopa that crosses the blood brain barrier by:

(A) increasing penetration of levodopa through BBB by complexation with it 

(B) decreasing peripheral metabolism of levodopa 

(C) decreasing metabolism of levodopa in the CNS 

(D) decreasing clearance of levodopa from the CNS 

11. Ethambutol molecule has:

(A) two chiral centers and 3 stereoisomers

(B) two chiral centers and 4 stereoisomers

(C) two chiral centers and 2 stereoisomers

(D) one chiral center and 2 stereoisomers

12. A compound will be sensitive towards IR radiation only when one of the following properties undergo transition on: 

(A) Polarizability 

(B) Dielectric constant

(C) Dipole moment 

(D) Refractivity

13.  X-ray crystallographic analysis of an optically active compound determines its:

(A) Optical rotatory dispersive power 

(B) Absolute configuration

(C) Relative configuration 

(D) Optical purity

14. Which one of the following statements is wrong? 

(A) A singlet or triplet state may result when one of the electrons from the HOMO is excited to higher energy levels 

(B) In an excited singlet state, the spin of the electron in the higher energy orbital is 

paired with the electron in the ground state orbital 

(C) Triplet excited state is more stable than the singlet excited state

(D) When the electron from the singlet excited state returns to ground state, the 

molecule always shows fluorescence phenomenon 

15. Aminotransferases usually require the following for their activity :

(A) Niacinamide 

(B)Vitamin B12

(C) Pyridoxal phosphate 

(D) Thiamine

1. What is a plasminogen activator?

Plasminogen activators help convert plasminogen into plasmin, which dissolves blood clots. Streptokinase is a plasminogen activator.

2. Which drug is used to diagnose Myasthenia Gravis?

Edrophonium is used as a diagnostic tool for Myasthenia Gravis due to its short-acting inhibition of acetylcholinesterase.

3. Which drug inhibits calcineurin in activated T-lymphocytes?

Tacrolimus is a calcineurin inhibitor that suppresses T-cell activation and is used as an immunosuppressant.

4. What is the chemical behavior of morphine alkaloid?

Morphine is basic in nature due to its nitrogen-containing structure.

5. In which ionic form does a compound exist at physiological pH?

Most weak bases exist in the cationic form at physiological pH, while weak acids remain in their unionized form.

6. Which drug is a mood stabilizer for bipolar disorder?

Lithium is commonly used as a mood stabilizer in bipolar disorder.

7. What is an isosteric replacement for a carboxylic acid group?

Tetrazole is often used as a bioisosteric replacement for carboxyl groups in drug design.

8. What is an example of an ansamycin antibiotic?

Rifamycin belongs to the ansamycin class of antibiotics, used primarily for tuberculosis treatment.

9. What type of metabolism does Glyburide undergo?

Glyburide undergoes O-demethylation, aromatic oxidation, and benzylic hydroxylation, but not amide hydrolysis.

10. How does Carbidopa enhance Levodopa’s effect in Parkinson’s disease?

Carbidopa decreases the peripheral metabolism of Levodopa, allowing more of it to reach the brain.

11. How many stereoisomers does Ethambutol have?

Ethambutol has two chiral centers and four stereoisomers.

12. What property makes a compound sensitive to IR radiation?

A compound is sensitive to IR radiation when there is a change in its dipole moment during vibrations.

13. What does X-ray crystallographic analysis determine for an optically active compound?

It determines the absolute configuration of a compound.

14. Why is the triplet excited state more stable than the singlet excited state?

In the triplet state, electrons have parallel spins, reducing repulsion and increasing stability compared to the singlet state.

15. Which coenzyme is required for aminotransferase enzyme activity?

Pyridoxal phosphate (Vitamin B6) is required for aminotransferase activity.

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