MCQOPTIONS
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MCQOPTIONS
This section includes 226 Mcqs, each offering curated multiple-choice questions to sharpen your Biochemistry knowledge and support exam preparation. Choose a topic below to get started.
| 1. |
Identify the amino acids containing nonpolar, aliphatic R groups. |
| A. | Phenylalanine, tyrosine, and tryptophan |
| B. | Glycine, alanine, leucine |
| C. | Lysine, arginine, histidine |
| D. | Serine, threonine, cysteine |
| Answer» C. Lysine, arginine, histidine | |
| 2. |
Which of the following compound is not involved in Edman degradation? |
| A. | Phenylisothiocyanate |
| B. | CF₃COOH |
| C. | FDNB |
| D. | Phenylthiocarbonyl |
| Answer» D. Phenylthiocarbonyl | |
| 3. |
Amino acids become negatively charged in the presence of |
| A. | acidic conditions |
| B. | alkaline conditions |
| C. | enzymes |
| D. | none of above |
| Answer» C. enzymes | |
| 4. |
In a native PAGE, proteins are separated on the basis of |
| A. | net negative charge |
| B. | net charge and size |
| C. | net positive charges size |
| D. | net positive charge |
| Answer» C. net positive charges size | |
| 5. |
Hemoglobin is a __________ |
| A. | Monomer |
| B. | Dimer |
| C. | Trimer |
| D. | Tetramer |
| Answer» E. | |
| 6. |
If the egg white protein, ovalbumin, is denatured in a hard-boiled egg, then which of the following is least affected? |
| A. | The primary structure of ovalbumin |
| B. | The secondary structure of ovalbumin |
| C. | The tertiary structure of ovalbumin |
| D. | The quaternary structure of ovalbumin |
| Answer» B. The secondary structure of ovalbumin | |
| 7. |
Which among the following is both glucogenic and ketogenic? |
| A. | Isoleucine |
| B. | Leucine |
| C. | Lysine |
| D. | Histidine |
| Answer» B. Leucine | |
| 8. |
Cleaving of peptide chain is done by _________ |
| A. | Trypsin |
| B. | Tyrosine |
| C. | Tryptophan |
| D. | Arginine |
| Answer» B. Tyrosine | |
| 9. |
The same peptide, Val-Lys-Glu-Met-Ser-Trp-Arg-Ala. was digested with chymotrypsin to produce |
| A. | Val-Lys + Glu-Met-Ser + Trp-Arg-Ala. |
| B. | Val-Lys-Glu-Met-Ser-Trp + Arg-Ala. |
| C. | Val-Lys-Glu-Met-Ser + Trp-Arg-Ala. |
| D. | Val-Lys-Glu-Met + Ser-Trp-Arg-Ala. |
| Answer» C. Val-Lys-Glu-Met-Ser + Trp-Arg-Ala. | |
| 10. |
What would happen if the anti-human Ig-conjugate is not washed free of the well before the substrate is added? |
| A. | The ELISA would not develop when the substrate was added |
| B. | The ELISA would develop normally |
| C. | All wells would show uniform over-development due to unbound and excess anti-human Ig enzyme conjugate |
| D. | None of the above |
| Answer» D. None of the above | |
| 11. |
In Rocket Immunodiffusion the length of the rocket is |
| A. | proportional to the amount of antibody placed in each well |
| B. | inversely proportional to the amount of antibody placed in each well |
| C. | inversely proportional to the amount of antigen placed in each well |
| D. | proportional to the amount of antigen placed in each well |
| Answer» E. | |
| 12. |
BRACl, an inherited form of breast cancer, regulates cell division by |
| A. | binding to a DNA sequence |
| B. | complexing with cyclins |
| C. | binding to the cell outer membrane |
| D. | binding to the protein RAD 51 which repairs DNA damage |
| Answer» E. | |
| 13. |
In deoxy hemoglobin (Hb), the Fe (II) is coordinated to |
| A. | four nitrogens of heme, the proximal His, and a water molecule |
| B. | four nitrogens of heme and to a water molecule |
| C. | two nitrogens of heme and to three His residues in Hb |
| D. | two nitrogens of heme and to three water molecules |
| Answer» B. four nitrogens of heme and to a water molecule | |
| 14. |
The different orders of protein structure are determined by all of the following bond types except |
| A. | peptide bonds |
| B. | phospho-diester bonds |
| C. | disulfide bridges |
| D. | hydrogen bonds |
| Answer» C. disulfide bridges | |
| 15. |
Which of the following is an imino acid? |
| A. | Alanine |
| B. | Glycine |
| C. | Proline |
| D. | Serine |
| Answer» D. Serine | |
| 16. |
Unpaired H-bond donors and acceptors are found in the hydrophobic core of a protein |
| A. | only at the ends of a-helices |
| B. | only at the turns connecting p-strands |
| C. | only on Pro residues |
| D. | rarely |
| Answer» E. | |
| 17. |
What is approximatively the half life of 32-Phosphorus? |
| A. | 14 days |
| B. | 28 days |
| C. | 42 days |
| D. | 30 days |
| Answer» B. 28 days | |
| 18. |
Among their selves, the molecules of amino acids |
| A. | react |
| B. | repel |
| C. | dissolve |
| D. | fuse |
| Answer» B. repel | |
| 19. |
In a gel filtration column |
| A. | smaller proteins enter the beads more readily |
| B. | large proteins elute first |
| C. | both (a) and (b) |
| D. | large proteins enter the beads more readily |
| Answer» D. large proteins enter the beads more readily | |
| 20. |
Which of the following radioactive element is generally involved in RIA? |
| A. | Tritium |
| B. | Carbon-14 |
| C. | Iodine-125 |
| D. | All of these |
| Answer» E. | |
| 21. |
Radial Immunodiffusion is similar to |
| A. | double-diffusion |
| B. | gel diffusion |
| C. | Ouchterloney technique |
| D. | all of these |
| Answer» B. gel diffusion | |
| 22. |
Hydrogen bonds in a-helices are |
| A. | more numerous than Vander Waals interactions |
| B. | not present at Phe residues |
| C. | analogous to the steps in a spiral staircase |
| D. | roughly parallel to the helix axis |
| Answer» E. | |
| 23. |
If the cyclic-side chain is bonded to both the nitrogen (N) and α-Carbon atom of the amino group, the structure becomes that of |
| A. | amino acid |
| B. | Gln |
| C. | amino acid |
| D. | Try |
| Answer» E. | |
| 24. |
The strong intermolecular forces between amino acids are due to the presence of |
| A. | azonium ion |
| B. | zwitterions ion |
| C. | uranium ion |
| D. | plutonium ion |
| Answer» C. uranium ion | |
| 25. |
An antigen preparation and an antibody preparation are tested by immunodiffusion. Three bands are found, indicating that |
| A. | there was more than one antigen |
| B. | the antibody was impure |
| C. | the temperature was too high |
| D. | there was one antibody and one antigen |
| Answer» B. the antibody was impure | |
| 26. |
Different form of a plasmid, on an agarose gel, after electrophoresis may be in which of the following sequence in decreasing molecular weight? |
| A. | Open circular, super coiled, linear plasmid DNA |
| B. | Linear plasmid, open circular, super coiled plasmid |
| C. | Open circular, super coiled, linear plasmid DNA |
| D. | Open circular, linear plasmid, super coiled plasmid |
| Answer» C. Open circular, super coiled, linear plasmid DNA | |
| 27. |
Signal sequences are part of a protein that |
| A. | signal folding of the protein |
| B. | signal the protein synthesis on the ribosomes is ended |
| C. | transport proteins to other sites within the cell |
| D. | refold proteins in prion-associated diseases |
| Answer» D. refold proteins in prion-associated diseases | |
| 28. |
In cells, amino acids used to build proteins are |
| A. | 10 |
| B. | 12 |
| C. | 20 |
| D. | 22 |
| Answer» D. 22 | |
| 29. |
Disulfide bonds most often stabilize the native structure of |
| A. | extracellular proteins |
| B. | dimeric proteins |
| C. | hydrophobic proteins |
| D. | intracellular proteins |
| Answer» B. dimeric proteins | |
| 30. |
The Ramachandran Plot illustrates the fact that |
| A. | the peptide bond is planar |
| B. | the F & Y angles can assume any value in a peptide |
| C. | the F & Y angles can assume only a single value in a protein |
| D. | the F & Y angles can assume approximately three different values |
| Answer» E. | |
| 31. |
Polar side chains in amino acids does not include |
| A. | Ala |
| B. | Val |
| C. | Asp |
| D. | all of above |
| Answer» E. | |
| 32. |
The oxygen in hemoglobin and myoglobin is bound to |
| A. | the iron atom in the heme group |
| B. | the nitrogen atoms on the heme |
| C. | histidine residues in the protein |
| D. | lysine residues in the protein |
| Answer» B. the nitrogen atoms on the heme | |
| 33. |
A large protein for muscles is built up from our food for |
| A. | brain |
| B. | muscles |
| C. | bones |
| D. | nails |
| Answer» C. bones | |
| 34. |
Unfolding of a protein can be termed as _________ |
| A. | Renaturation |
| B. | Denaturation |
| C. | Oxidation |
| D. | Reduction |
| Answer» C. Oxidation | |
| 35. |
RAST test (radio allergosorbent test) is often used to detect |
| A. | antibodies associated with allergies (IgE) |
| B. | antigen associated with allergies (IgE) |
| C. | bacteriophages |
| D. | None of the above |
| Answer» B. antigen associated with allergies (IgE) | |
| 36. |
Which of the following is a true statement? |
| A. | Tryptophan and tyrosine are significantly more polar than phenylalanine |
| B. | Leucine is commonly used as an ingredient in the buffers of SDS page |
| C. | Aspartate is an essential amino acid |
| D. | Lysine is a non-essential amino acid |
| Answer» B. Leucine is commonly used as an ingredient in the buffers of SDS page | |
| 37. |
Which part of the amino acid gives it uniqueness? |
| A. | Amino group |
| B. | Carboxyl group |
| C. | Side chain |
| D. | None of the mentioned |
| Answer» D. None of the mentioned | |
| 38. |
What are the following is not a factor responsible for the denaturation of proteins? |
| A. | pH change |
| B. | Organic solvents |
| C. | Heat |
| D. | Charge |
| Answer» E. | |
| 39. |
Hydrolysis can break linkages of |
| A. | amides only |
| B. | peptides only |
| C. | fat chains |
| D. | amides and peptides |
| Answer» E. | |
| 40. |
Attractive Vander Waals forces occur between |
| A. | apolar molecules in the liquid state |
| B. | any pair of nearby atoms |
| C. | polar molecules in the solid state |
| D. | only if other forces are less favorable |
| Answer» C. polar molecules in the solid state | |
| 41. |
Peptide bond is a _________ |
| A. | Covalent bond |
| B. | Ionic bond |
| C. | Metallic bond |
| D. | Hydrogen bond |
| Answer» B. Ionic bond | |
| 42. |
The salt which produces salting out effect during extraction of proteins is? |
| A. | NH₄SO₄ |
| B. | (NH₄)₂SO₄ |
| C. | (NH₄)₃SO₄ |
| D. | NaCl |
| Answer» C. (NH₄)₃SO₄ | |
| 43. |
In 3° structure of proteins, folding and shaping is done by __________ |
| A. | Hydrophobic interactions |
| B. | Polar interactions |
| C. | Hydrogen bonding |
| D. | None of the mentioned |
| Answer» B. Polar interactions | |
| 44. |
2-amino carboxylic acid is building block in manufacturing of |
| A. | fats |
| B. | proteins |
| C. | vitamins |
| D. | minerals |
| Answer» C. vitamins | |
| 45. |
Which of the following statements is true about affinity chromatography? |
| A. | During the separation of a mixture of proteins, the protein which does not bind to ligand is eluted first |
| B. | During the separation of a mixture of proteins, the protein which does not bind to ligand is eluted last |
| C. | During the separation of a mixture of proteins, the protein which binds to ligand is eluted first |
| D. | Unwanted proteins are eluted by ligand solution |
| Answer» B. During the separation of a mixture of proteins, the protein which does not bind to ligand is eluted last | |
| 46. |
Which of the following statements is true about size-exclusion chromatography? |
| A. | During the separation of a mixture of proteins, protein with smallest molecular weight is eluted first |
| B. | During the separation of a mixture of proteins, protein with largest molecular weight is eluted first |
| C. | During the separation of a mixture of proteins, protein with largest molecular weight is eluted last |
| D. | During the separation of a mixture of proteins, protein with largest molecular weight flow around the beads |
| Answer» C. During the separation of a mixture of proteins, protein with largest molecular weight is eluted last | |
| 47. |
The factor which does not affect pKₐ value of an amino acid is _________ |
| A. | The loss of charge in the α-carboxyl and α-amino groups |
| B. | The interactions with other peptide R groups |
| C. | Other environmental factors |
| D. | Molecular weight |
| Answer» E. | |
| 48. |
Amino acids sequence in DNA can be determined by the order of their _________ |
| A. | rRNA |
| B. | tRNA |
| C. | Nucleotides |
| D. | mRNA |
| Answer» D. mRNA | |
| 49. |
Native state of a protein can be disrupted by __________ |
| A. | Temperature |
| B. | pH |
| C. | Removal of water |
| D. | Presence of hydrophilic surfaces |
| Answer» E. | |
| 50. |
Which of the following is a positively charged matrix for ion exchange chromatography? |
| A. | CM cellulose |
| B. | DEAE cellulose |
| C. | Phosphocellulose |
| D. | None of these |
| Answer» C. Phosphocellulose | |