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.
| 151. |
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 | |
| 152. |
Which of the following amino acid is known as half-cystine residue? |
| A. | Cysteine |
| B. | Isoleucine |
| C. | Valine |
| D. | Histidine |
| Answer» B. Isoleucine | |
| 153. |
Protein fluorescence arises primarily from which residue? |
| A. | Arginine |
| B. | Tryptophan |
| C. | Tyrosine |
| D. | Phenylalanine |
| Answer» C. Tyrosine | |
| 154. |
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 | |
| 155. |
D-Alanine and L-Alanine are technically known as |
| A. | anomers |
| B. | enantiomers |
| C. | epimers |
| D. | polymer |
| Answer» C. epimers | |
| 156. |
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. | |
| 157. |
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 | |
| 158. |
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 | |
| 159. |
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. | |
| 160. |
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. | |
| 161. |
The conformational changes from the T to the R state is initiated by |
| A. | binding of oxygen to the heme |
| B. | movement of the proximal histidine towards the heme |
| C. | movement of the F-helix, which contains the proximal His |
| D. | reorganization of protein-protein contacts between the individual subunits |
| Answer» B. movement of the proximal histidine towards the heme | |
| 162. |
The Hill coefficient (nH) for myoglobin and hemoglobin are respectively |
| A. | 2.8 and 1.0 |
| B. | 1.0 and 2.8 |
| C. | 1.2 and 4.5 |
| D. | 4.5 and 1.2 |
| Answer» C. 1.2 and 4.5 | |
| 163. |
Bisphosphoglycerate (BPG) cannot bind to the oxygenated R state of hemoglobin because |
| A. | it is displaced from the heme by oxygen |
| B. | it is displaced from the heme by movement of the proximal histidine |
| C. | its binding pocket becomes too small to accommodate BPG |
| D. | BPG binds to the R state with the same affinity as the T state |
| Answer» D. BPG binds to the R state with the same affinity as the T state | |
| 164. |
Which of the following is a nonprotein amino acid? |
| A. | Dopamine |
| B. | Hydroxylysine |
| C. | Cystine |
| D. | None of these |
| Answer» B. Hydroxylysine | |
| 165. |
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 | |
| 166. |
Small molecules affect hemoglobin (Hb) by |
| A. | decreasing Hb affinity for O₂ |
| B. | increasing [H+] |
| C. | increasing Hb affinity for O₂ |
| D. | increasing [H+] and decreasing Hb affinity for O₂ |
| Answer» E. | |
| 167. |
O₂ binding to hemoglobin results in |
| A. | 100-fold higher affinity for the last O₂ bound than for the first |
| B. | extensive protein conformational change |
| C. | both (a) and (b) |
| D. | 100-fold lower affinity for the last O₂ bound than for the first |
| Answer» D. 100-fold lower affinity for the last O₂ bound than for the first | |
| 168. |
When protein binds two ligands in a non-cooperative manner, then the x-intercept of the Scatchard Plot is |
| A. | 1 |
| B. | 2 |
| C. | not defined |
| D. | none of the above |
| Answer» C. not defined | |
| 169. |
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 | |
| 170. |
What is the product of the catabolic breakdown of Arginine? |
| A. | Alpha-ketoglutarate |
| B. | Fumarate |
| C. | Oxaloacetate |
| D. | Succinate |
| Answer» B. Fumarate | |
| 171. |
Which of the following amino acid contain an imidazolium moiety? |
| A. | Alanine |
| B. | Valine |
| C. | Cysteine |
| D. | Histidine |
| Answer» E. | |
| 172. |
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 | |
| 173. |
What is the product of the catabolic breakdown of Alanine? |
| A. | Fumarate |
| B. | Oxaloacetate |
| C. | Pyruvate |
| D. | Malate |
| Answer» D. Malate | |
| 174. |
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 | |
| 175. |
Which of the following is not the hydrophobic and aromatic amino acid? |
| A. | Phenylalanine |
| B. | Tyrosine |
| C. | Tryptophan |
| D. | None of these |
| Answer» E. | |
| 176. |
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 | |
| 177. |
The side chains in amino acids can be |
| A. | acidic only |
| B. | basic only |
| C. | neutral |
| D. | acidic and basic |
| Answer» E. | |
| 178. |
Conversion of amino acid in useful proteins is carried out by |
| A. | centriole |
| B. | cytoplasm |
| C. | protoplasm |
| D. | Nucleoplasm |
| Answer» C. protoplasm | |
| 179. |
The average molecular weight of an amino acid residue in a protein is about _________ |
| A. | 128 |
| B. | 118 |
| C. | 110 |
| D. | 120 |
| Answer» D. 120 | |
| 180. |
An allosteric activator |
| A. | increases the binding affinity |
| B. | decreases the binding affinity |
| C. | stabilizes the R state of the protein |
| D. | both (a) and (c) |
| Answer» E. | |
| 181. |
Which of the following is an immunoelectrophoresis technique? |
| A. | Two-dimensional immunoelectrophoresis |
| B. | Counterimmunoelectrophoresis |
| C. | Coimmunoelectrophoresis |
| D. | Both (a) and (b) |
| Answer» E. | |
| 182. |
How many different amino acids are there? |
| A. | 3 |
| B. | 20 |
| C. | 100 |
| D. | An infinite number |
| Answer» C. 100 | |
| 183. |
Which of the following information is responsible to specify the three-dimensional shape of a protein? |
| A. | The protein’s peptide bond |
| B. | The protein’s amino acid sequence |
| C. | The protein’s interaction with other polypeptides |
| D. | The protein’s interaction with molecular chaperons |
| Answer» C. The protein’s interaction with other polypeptides | |
| 184. |
Rocket Immunodiffusion is also known as |
| A. | gel diffusion |
| B. | electroimmunodiffusion |
| C. | double-diffusion |
| D. | none of these |
| Answer» C. double-diffusion | |
| 185. |
In the β-pleated sheet |
| A. | hydrogen bonds are formed between the peptide bonds |
| B. | adjacent polypeptide chains can either be parallel or antiparallel |
| C. | the polypeptide chain is fully extended |
| D. | all of the above |
| Answer» E. | |
| 186. |
The IPTG is a gratuitous inducers of (β-galactosidase, and x-gal is a chromogenic substrate. When α-complementation occurs which colour is produced? |
| A. | Blue |
| B. | White |
| C. | Brown |
| D. | No colour is produced |
| Answer» B. White | |
| 187. |
The subunit molecular weight as well as the number of subunits in the quaternary structure can be determined by |
| A. | SDS-PAGE electrophoresis |
| B. | gel filtration chromatography |
| C. | combining information from (a)and (b) |
| D. | isoelectric focusing |
| Answer» D. isoelectric focusing | |
| 188. |
Over 50% of common cancers are associated with damage to a protein, p53. This protein |
| A. | is a cyclin |
| B. | is a tumor supressor |
| C. | is an oncogene |
| D. | regulates apoptosis |
| Answer» C. is an oncogene | |
| 189. |
Hemoglobin has quaternary structure and is made up of |
| A. | six polypeptide chains, two α-chains and four β-chains |
| B. | two polypeptide chains, one α-chains and one β-chains |
| C. | four polypeptide chains, two α-chains and two β-chains |
| D. | five polypeptide chains, two α-chains and three β-chains |
| Answer» D. five polypeptide chains, two α-chains and three β-chains | |
| 190. |
The molecular formula for glycine is C₂H₅O₂N. What would be the molecular formula for a linear oligomer made by linking ten glycine molecules together by condensation synthesis? |
| A. | C₂₀H₅₀O₂₀N₁₀ |
| B. | C₂₀H₃₂O₁₁N₁₀ |
| C. | C₂₀H₄₀O₁₀N₁₀ |
| D. | C₂₀H₆₈O₂₉N₁₀ |
| Answer» C. C₂₀H₄₀O₁₀N₁₀ | |
| 191. |
When pO₂ = Kd of myoglobin, the fractional saturation (YO₂) is about |
| A. | 0.1 |
| B. | 0.5 |
| C. | 0.9 |
| D. | 1.7 |
| Answer» C. 0.9 | |
| 192. |
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. | |
| 193. |
In ion-exchange chromatography |
| A. | proteins are separated on the basis of their net charge |
| B. | proteins are separated on the basis of their size |
| C. | proteins are separated on the basis of their shape |
| D. | either (b) or (c) |
| Answer» B. proteins are separated on the basis of their size | |
| 194. |
The pattern on paper in chromatography is called __________ |
| A. | Chroming |
| B. | Chroma |
| C. | Chromatograph |
| D. | Chromatogram |
| Answer» E. | |
| 195. |
Which of the following is an essential amino acid? |
| A. | Cysteine |
| B. | Asparagine |
| C. | Glutamine |
| D. | Phenylalanine |
| Answer» E. | |
| 196. |
Which of the following is false? |
| A. | The two main types of secondary structure are the α helix and β pleet structures |
| B. | α helix is a right handed coiled strand |
| C. | The hydrogen bonding in a β-sheet is between strands rather than within strands |
| D. | The hydrogen bonding in a β-sheet is within strands rather than between strands |
| Answer» E. | |
| 197. |
Which of the following is a Sanger’s reagent? |
| A. | 1-fluoro-2, 4-dinitrobenzene |
| B. | 1-fluoro-2, 3-dinitrobenzene |
| C. | 1-fluoro-2, 4-trinitrobenzene |
| D. | 1-fluoro-2, 3-trinitrobenzene |
| Answer» B. 1-fluoro-2, 3-dinitrobenzene | |
| 198. |
The specificity of a ligand binding site on a protein is based on |
| A. | the absence of competing ligands |
| B. | the amino acid residues lining the binding site |
| C. | the presence of hydrating water molecules |
| D. | the opposite chirality of the binding ligand |
| Answer» C. the presence of hydrating water molecules | |
| 199. |
Proteins can be visualized directly in gels by |
| A. | staining them with the dye |
| B. | using electron microscope only |
| C. | measuring their molecular weight |
| D. | none of these |
| Answer» B. using electron microscope only | |
| 200. |
The pH of many body tissues is |
| A. | below 5 |
| B. | near 7 |
| C. | near 10 |
| D. | near 14 |
| Answer» C. near 10 | |