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.
| 101. |
A reaction in which organic molecules join together along with the elimination of water molecule or HCl is called |
| A. | addition |
| B. | substitution |
| C. | condensation |
| D. | evaporation |
| Answer» D. evaporation | |
| 102. |
The peptide bond in proteins is |
| A. | only found between proline residues |
| B. | usually cis unless proline is the next amino acid |
| C. | usually trans unless proline is the next amino acid |
| D. | is planar because of steric hinderance |
| Answer» D. is planar because of steric hinderance | |
| 103. |
Amino acids are not used for |
| A. | formation of enzymes |
| B. | formation of hormones |
| C. | repair of worn out body parts |
| D. | detoxication of benzoic acid |
| Answer» E. | |
| 104. |
What is the ELISA test intended to measure? |
| A. | Antibody to HIV only |
| B. | Antigen to HIV only |
| C. | Presence of free, circulating virus in the patient |
| D. | Antibodies directed against HLA molecules |
| Answer» B. Antigen to HIV only | |
| 105. |
In SDS-PAGE, the protein sample is first |
| A. | treated with a reducing agent and then with anionic detergent followed by fractionation by electrophoresis |
| B. | fractionated by electrophoresis then treated with an oxidizing agent followed by anionic detergent. |
| C. | treated with a oxidizing agent and then with anionic detergent followed by fractionation by electrophoresis |
| D. | none of the above |
| Answer» B. fractionated by electrophoresis then treated with an oxidizing agent followed by anionic detergent. | |
| 106. |
An oil drop with a polar coat is a metaphor referring to the three dimensional structure of |
| A. | fibrous proteins |
| B. | collagen |
| C. | globular proteins |
| D. | silk protein |
| Answer» D. silk protein | |
| 107. |
The heme is held in place by a bond between |
| A. | the Fe²⁺ and cysteine |
| B. | the Fe³⁺ and histidine |
| C. | the Fe³⁺ and cysteine |
| D. | the Fe²⁺ and histidine |
| Answer» E. | |
| 108. |
Longer chains of amino acids form polymers bonded via amide link is called |
| A. | peptide |
| B. | poly peptide |
| C. | amine |
| D. | amide |
| Answer» C. amine | |
| 109. |
Amine group reacts in the excess of acid to produce |
| A. | ammonia |
| B. | ammonium salts |
| C. | ammonium ions |
| D. | nitrogen |
| Answer» C. ammonium ions | |
| 110. |
Excess of amino acids are |
| A. | immediately used in cell respiration |
| B. | converted in proteins |
| C. | converted to urea |
| D. | converted to glycogen |
| Answer» D. converted to glycogen | |
| 111. |
Which of the following is Edman reagent? |
| A. | Phenylisothiocyanate |
| B. | CF₃COOH |
| C. | FDNB |
| D. | Phenylthiocarbonyl |
| Answer» B. CF₃COOH | |
| 112. |
Edman degradation is used for _________ |
| A. | Identifying N-terminal amino acids |
| B. | Identifying C-terminal amino acids |
| C. | Identifying amino acid |
| D. | Identifying carbohydrates |
| Answer» B. Identifying C-terminal amino acids | |
| 113. |
Which of the following is the correct order of sequencing? |
| A. | Cleaving, sequencing and ordering |
| B. | Sequencing, ordering and cleaving |
| C. | Ordering, cleaving and sequencing |
| D. | Ordering, sequencing and cleaving |
| Answer» B. Sequencing, ordering and cleaving | |
| 114. |
Which of the following statements is false? |
| A. | The term activity refers to the total units of enzyme in a solution |
| B. | The specific activity is a measure of enzyme purity |
| C. | Specific activity increases during purification of an enzyme and becomes maximal and constant when the enzyme is pure |
| D. | Specific activity decreases during purification of an enzyme and becomes maximal and constant when the enzyme is pure |
| Answer» E. | |
| 115. |
What best summarizes the MALDI method by which gas phase ions are produced for mass spectrometry? |
| A. | Sample is hit by a low energy xenon beam |
| B. | Sample is forced through a narrow capillary tube and the solvent rapidly evaporates |
| C. | Sample is embedded in a crystalline matrix and bombarded by laser beams |
| D. | Sample is heated and then bombarded by electrons |
| Answer» D. Sample is heated and then bombarded by electrons | |
| 116. |
Amino acids that is secondary among these is |
| A. | Ala |
| B. | Pro |
| C. | Gln |
| D. | Try |
| Answer» C. Gln | |
| 117. |
Which of the following is not the classified form of conjugated proteins? |
| A. | Lipoproteins |
| B. | Glycoproteins |
| C. | Metalloproteins |
| D. | Complete proteins |
| Answer» E. | |
| 118. |
Which of the following statements about column chromatography is correct? |
| A. | Resolution increases as the length of the column increases |
| B. | Mobile phase is a porous solid material with appropriate chemical properties held in the column |
| C. | Stationary phase is a buffered solution that percolates through mobile phase |
| D. | Large proteins emerge from the column sooner than small ones |
| Answer» B. Mobile phase is a porous solid material with appropriate chemical properties held in the column | |
| 119. |
An average polypeptide chain may contain up to |
| A. | 300 amino acids |
| B. | 400 amino acids |
| C. | 500 amino acids |
| D. | more than 500 amino acids |
| Answer» D. more than 500 amino acids | |
| 120. |
On addition of alkali, zwitterion ion will reform |
| A. | amine |
| B. | carboxylic group |
| C. | alcohol |
| D. | carbonic acid |
| Answer» B. carboxylic group | |
| 121. |
The best way to determine the location of protein in the purification scheme is to measure the |
| A. | rate of ATP synthesis |
| B. | changes in the refractive index |
| C. | UV absorption |
| D. | mass spectroscopy of the protein |
| Answer» B. changes in the refractive index | |
| 122. |
Proteins are found in |
| A. | hair |
| B. | skin |
| C. | tendons |
| D. | all of above |
| Answer» E. | |
| 123. |
Ion which carries two charges, positive and negative is called |
| A. | azonium ion |
| B. | zwitterions ion |
| C. | uranium ion |
| D. | plutonium ion |
| Answer» C. uranium ion | |
| 124. |
Which of the following is the most correct? |
| A. | Charged amino acids are never buried in the interior of a protein |
| B. | Charged amino acids are seldom buried in the interior of a protein |
| C. | All hydrophobic amino acids are buried when a protein folds |
| D. | Tyrosine is only found in the interior of proteins |
| Answer» C. All hydrophobic amino acids are buried when a protein folds | |
| 125. |
Gel-filtration chromatography separates on the basis of |
| A. | size and shape using porous beads packed in a column |
| B. | size using porous beads packed in a column |
| C. | shape using porous beads packed in a column |
| D. | none of the above |
| Answer» B. size using porous beads packed in a column | |
| 126. |
Proteins are the natural |
| A. | polymers |
| B. | non-absorbents |
| C. | absorbents |
| D. | non-polymers |
| Answer» B. non-absorbents | |
| 127. |
Amino acids which are not made by enzymes in our body are called |
| A. | essential amino acids |
| B. | non-essential amino acids |
| C. | polymers |
| D. | monomers |
| Answer» B. non-essential amino acids | |
| 128. |
Agarose a porous matrix used in various molecular biology technique is made by repetitive units of |
| A. | maltose |
| B. | agarobiose |
| C. | agar |
| D. | none of these |
| Answer» B. agarobiose | |
| 129. |
In isoelectric focusing, proteins are separated on the basis of their |
| A. | relative content of positively charged residue only |
| B. | relative content of negatively charged residue only |
| C. | size |
| D. | relative content of positively and negatively charged residue |
| Answer» E. | |
| 130. |
Buried hydrophobic side chains in a globular protein fit into a hole formed by the side chains of |
| A. | 1-3 other amino acids |
| B. | 5-7 other amino acids |
| C. | 9-12 other amino acids |
| D. | 13-15 other amino acids |
| Answer» C. 9-12 other amino acids | |
| 131. |
What would happen if serum is omitted from the ELISA, but all other steps remain same? |
| A. | Anti-human Ig-conjugate would not bind and be washed away |
| B. | The OD values would be nearly the same as the assay control |
| C. | Both (a) and (b) |
| D. | Anti-human Ig-conjugate would bind non-specifically to the ELISA plate |
| Answer» D. Anti-human Ig-conjugate would bind non-specifically to the ELISA plate | |
| 132. |
The group which may vary in different amino acids is |
| A. | R-group |
| B. | P-group |
| C. | S-group |
| D. | N-group |
| Answer» B. P-group | |
| 133. |
Two chains of amino acids in an insulin molecule are held together by __________ |
| A. | Sulfide bridges |
| B. | Disulfide bridges |
| C. | Peptide bond |
| D. | Covalent linkage |
| Answer» C. Peptide bond | |
| 134. |
A tripeptide has _________ |
| A. | 3 amino acids and 1 peptide bond |
| B. | 3 amino acids and 2 peptide bonds |
| C. | 3 amino acids and 3 peptide bonds |
| D. | 3 amino acids and 4 peptide bonds |
| Answer» C. 3 amino acids and 3 peptide bonds | |
| 135. |
Which of the following is a 39-residue hormone of the anterior pituitary gland? |
| A. | Corticotropin |
| B. | Glucagon |
| C. | Insulin |
| D. | Bradykinin |
| Answer» B. Glucagon | |
| 136. |
During the formation of the peptide bond which of the following takes place? |
| A. | Hydroxyl group is lost from its carboxyl group of one amino acid and a hydrogen atom is lost from its amino group of another amino acid |
| B. | Hydrogen atom is lost from its carboxyl group of one amino acid and a hydroxyl group is lost from its amino group of another amino acid |
| C. | Hydroxyl group is lost from its carboxyl group of one amino acid and a hydroxyl group is lost from its amino group of another amino acid |
| D. | Hydrogen atom is lost from its carboxyl group of one amino acid and a hydrogen atom is lost from its amino group of another amino acid |
| Answer» B. Hydrogen atom is lost from its carboxyl group of one amino acid and a hydroxyl group is lost from its amino group of another amino acid | |
| 137. |
The oxygen binding curves of hemoglobin and myoglobin |
| A. | allow maximum transfer of oxygen to the tissues |
| B. | are a consequence of the quaternary structure of hemoglobin |
| C. | both (a) and (b) |
| D. | are identical |
| Answer» D. are identical | |
| 138. |
Beta pleated sheets are examples of protein's |
| A. | primary structure |
| B. | secondary structure |
| C. | tertiary structure |
| D. | quaternary structure |
| Answer» C. tertiary structure | |
| 139. |
Which of the following is an immunodiffusion test? |
| A. | Double-diffusion |
| B. | Gel diffusion |
| C. | Ouchterloney technique |
| D. | All of these |
| Answer» E. | |
| 140. |
A protein that binds two ligands in a non-cooperative manner will show |
| A. | a sigmodial binding curve |
| B. | a hyperbolic binding curve |
| C. | a linear Scatchard Plot |
| D. | both (b) and (c) |
| Answer» E. | |
| 141. |
Sickle cell disease is due to |
| A. | a mutation in the beta chain of Hb |
| B. | a mutation in the alpha chain of Hb |
| C. | infection with a parasite |
| D. | none of the above |
| Answer» B. a mutation in the alpha chain of Hb | |
| 142. |
In hemoglobin, allosteric effects occur |
| A. | only in humans |
| B. | for maintaining Fe in the Fe2+ state |
| C. | to minimize oxygen delivery to the tissues |
| D. | to maximize oxygen delivery to the tissues |
| Answer» E. | |
| 143. |
Affinity chromatography deals with the |
| A. | specific binding of a protein constituents for another molecule |
| B. | protein - protein interaction |
| C. | protein - carbohydrate interaction |
| D. | none of the above |
| Answer» B. protein - protein interaction | |
| 144. |
Which of the following is not an essential amino acid? |
| A. | Aspartic acid |
| B. | Glutamic acid |
| C. | Glycine |
| D. | All of these |
| Answer» E. | |
| 145. |
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 | |
| 146. |
The major element of secondary structure in myoglobin and hemoglobin is |
| A. | the P-strand |
| B. | the a-helix |
| C. | the reverse turn |
| D. | All of these |
| Answer» C. the reverse turn | |
| 147. |
Enzymes, antibodies, and hormones are the basic needs for |
| A. | proteins |
| B. | calcium |
| C. | vitamin |
| D. | salts |
| Answer» B. calcium | |
| 148. |
A purified protein sample contains 10 μg of protein and has an enzyme activity of 1 m mole of ATP synthesized/sec (1 unit). What is the specific activity of the final purified sample? |
| A. | 1,000 units/mg |
| B. | 10,000 units/mg. |
| C. | 100,000 units/mg |
| D. | 1,000,000 units/mg |
| Answer» D. 1,000,000 units/mg | |
| 149. |
Which of the following may be added to stabilize the protein after yeast cells disruption? |
| A. | NaCl |
| B. | Protease inhibitor |
| C. | AMP |
| D. | All of these |
| Answer» E. | |
| 150. |
Which of the following is a nonstandard amino acid? |
| A. | Cysteine |
| B. | Isoleucine |
| C. | Hydroxyproline |
| D. | Histidine |
| Answer» D. Histidine | |