MCQOPTIONS
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MCQOPTIONS
This section includes 33 Mcqs, each offering curated multiple-choice questions to sharpen your Biochemistry knowledge and support exam preparation. Choose a topic below to get started.
| 1. |
When the amino acid alanine (R-group is CH3) is added to a solution with a pH of 7.3, alanine becomes |
| A. | a cation |
| B. | nonpolar |
| C. | a zwitterions |
| D. | an isotope |
| Answer» D. an isotope | |
| 2. |
The isoelectric point of an amino acid is defined as the pH |
| A. | where the molecule carries no electric charge |
| B. | where the carboxyl group is uncharged |
| C. | where the amino group is uncharged |
| D. | of maximum electrolytic mobility |
| Answer» B. where the carboxyl group is uncharged | |
| 3. |
Protein fluorescence arises primarily from which residue? |
| A. | Arginine |
| B. | Tryptophan |
| C. | Tyrosine |
| D. | Phenylalanine |
| Answer» C. Tyrosine | |
| 4. |
The sulphur containing side chain of cysteine is |
| A. | ampiphillic, highly reactive and capable of reacting with another cysteine |
| B. | hydrophillc, highly reactive and capable of reacting with another cysteine |
| C. | hydrophobic, highly reactive and capable of reacting with another cysteine |
| D. | none of the above |
| Answer» D. none of the above | |
| 5. |
Which of the following is a nonprotein amino acid? |
| A. | Dopamine |
| B. | Hydroxylysine |
| C. | Cystine |
| D. | None of these |
| Answer» B. Hydroxylysine | |
| 6. |
Coomassie Blue stains the proteins by reacting with |
| A. | arginine residues |
| B. | free c-termini |
| C. | peptide bonds |
| D. | aromatic ring |
| Answer» B. free c-termini | |
| 7. |
Which amino acid when exposed to ninhydrin produces a brown color? |
| A. | Asparagine |
| B. | Proline |
| C. | Alanine |
| D. | Valine |
| Answer» B. Proline | |
| 8. |
Stereo chemical configuration of all a-amino acids derived from proteins is |
| A. | L |
| B. | D |
| C. | L and D |
| D. | None of these |
| Answer» B. D | |
| 9. |
What is the product of the catabolic breakdown of Alanine? |
| A. | Fumarate |
| B. | Oxaloacetate |
| C. | Pyruvate |
| D. | Malate |
| Answer» D. Malate | |
| 10. |
Molecules that bear charged groups of opposite polarity are known as |
| A. | zwitterions |
| B. | ambions |
| C. | ion conversion |
| D. | amphions |
| Answer» B. ambions | |
| 11. |
An essential amino acid is one that |
| A. | is essentially easy to synthesize |
| B. | is essential to flagella motion |
| C. | the body cannot synthesize |
| D. | the body can synthesize under essential conditions |
| Answer» D. the body can synthesize under essential conditions | |
| 12. |
D-Alanine and L-Alanine are technically known as |
| A. | anomers |
| B. | enantiomers |
| C. | epimers |
| D. | polymer |
| Answer» C. epimers | |
| 13. |
Which amino acids would most likely reside in the membrane-anchoring domain of a membrane embedded protein? |
| A. | Isoleucine, valine and phenylalanine |
| B. | Phenylalanine, valine, and aspartate |
| C. | Leucine, threonine, and lysine |
| D. | Lysine, arginine and histidine |
| Answer» B. Phenylalanine, valine, and aspartate | |
| 14. |
Which of the following pairs of amino acids would carry a negative charge on their side chain at pH 8.0? |
| A. | Asparagine & Glutamine |
| B. | Leucine & Glycine |
| C. | Histidine & Lysine |
| D. | Aspartate & Glutamate |
| Answer» E. | |
| 15. |
Which pair of amino acids absorbs the most UV light at 280 nm? |
| A. | Threonine & Histidine |
| B. | Trp & Tyrosine |
| C. | Cystein & Asparagine |
| D. | Phenylalnine & Proline |
| Answer» C. Cystein & Asparagine | |
| 16. |
Which of the following is an essential amino acid? |
| A. | Tryptophan |
| B. | Methionine |
| C. | Lysine |
| D. | All of these |
| Answer» E. | |
| 17. |
Which of the following is not an essential amino acid? |
| A. | Aspartic acid |
| B. | Glutamic acid |
| C. | Glycine |
| D. | All of these |
| Answer» E. | |
| 18. |
How many different amino acids are there? |
| A. | 3 |
| B. | 20 |
| C. | 100 |
| D. | An infinite number |
| Answer» C. 100 | |
| 19. |
Which of the following is not a sensible grouping of amino acids based on their polarity properties? |
| A. | Ala, Leu, and Val |
| B. | Arg, His, and Lys |
| C. | Phe, Trp, and Tyr |
| D. | Asp, Ile, and Pro |
| Answer» E. | |
| 20. |
The sequence of letters 'WYQN' will represent |
| A. | Tryptophan, tyrosine, glutamic acid, asparagine |
| B. | Tryptophan, tyrosine, glutamine, asparagine |
| C. | Tryptophan, glutamine, tryptophan, asparagine |
| D. | Glutamine, tyrosine, tryptophan, aspartic acid |
| Answer» C. Tryptophan, glutamine, tryptophan, asparagine | |
| 21. |
Which of the following amino acid is known as half-cystine residue? |
| A. | Cysteine |
| B. | Isoleucine |
| C. | Valine |
| D. | Histidine |
| Answer» B. Isoleucine | |
| 22. |
What is the end product of leucine metabolism? |
| A. | Acetyl-CoA |
| B. | Pyruvic acid |
| C. | Oxaloacetic acid |
| D. | Acetyl carnitine |
| Answer» B. Pyruvic acid | |
| 23. |
What is the heaviest of the twenty amino acids? |
| A. | Phenylalanine |
| B. | Tryptophan |
| C. | Tyrosine |
| D. | Histidine |
| Answer» C. Tyrosine | |
| 24. |
Which of the following is a nonstandard amino acid? |
| A. | Cysteine |
| B. | Isoleucine |
| C. | Hydroxyproline |
| D. | Histidine |
| Answer» D. Histidine | |
| 25. |
Proteins and macromolecular structures take on their higher order structures |
| A. | by self-assembly |
| B. | with the help of molecular chaperons |
| C. | with the help of precursor sequences that are removed from the final structures |
| D. | all of the above |
| Answer» E. | |
| 26. |
Which of the following amino acids can form hydrogen bonds with their side (R) groups? |
| A. | Asparagine |
| B. | Aspartic acid |
| C. | Glutamine |
| D. | All of these |
| Answer» E. | |
| 27. |
Which of the following amino acid contain an imidazolium moiety? |
| A. | Alanine |
| B. | Valine |
| C. | Cysteine |
| D. | Histidine |
| Answer» E. | |
| 28. |
Serine and threonine are polar amino acids due to |
| A. | reactive hydroxyl group in the side chain |
| B. | reactive alcoholic group in the side chain |
| C. | reactive keto group in the side chain |
| D. | reactive aldehyde group in the side chain |
| Answer» B. reactive alcoholic group in the side chain | |
| 29. |
Which of the following is not the hydrophobic and aromatic amino acid? |
| A. | Phenylalanine |
| B. | Tyrosine |
| C. | Tryptophan |
| D. | None of these |
| Answer» E. | |
| 30. |
Amino acids required in the human diet and not synthesized by the body are called |
| A. | specialized |
| B. | trace |
| C. | essential |
| D. | accessory |
| Answer» D. accessory | |
| 31. |
The -amino acids have a carboxyl group with a pK around __________ , and an amino group with a pK near __________ . |
| A. | 1.1, and 12.1 |
| B. | 6.5, and 8.0 |
| C. | 3.3, and 10.5 |
| D. | 2.2, and 9.4 |
| Answer» E. | |
| 32. |
What is the product of the catabolic breakdown of Arginine? |
| A. | Alpha-ketoglutarate |
| B. | Fumarate |
| C. | Oxaloacetate |
| D. | Succinate |
| Answer» B. Fumarate | |
| 33. |
In a polypeptide average mass of an amino acid residue is |
| A. | 110 daltons |
| B. | 118 daltons |
| C. | 80 daltons |
| D. | 150 daltons |
| Answer» B. 118 daltons | |