MCQOPTIONS
Saved Bookmarks
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.
| 51. |
If the F and Y angles of each peptide unit in a protein are known, which of the following may also be determined? |
| A. | Complete secondary structure |
| B. | Complete tertiary structure |
| C. | Complete quaternary structure |
| D. | Thermodynamic stability |
| Answer» B. Complete tertiary structure | |
| 52. |
In β-pleated sheet structures neighbouring |
| A. | chains lie in a flat plane |
| B. | neighboring residues are hydrogen bonded |
| C. | neighboring chains are connected by a-helices |
| D. | neighboring chains are hydrogen bonded |
| Answer» E. | |
| 53. |
Individuals with PKU disease are mentally retarded unless |
| A. | phenylalanine in the diet is restricted |
| B. | tyrosine in the diet is restricted |
| C. | homogentisic acid in the diet is restricted |
| D. | none of the above |
| Answer» B. tyrosine in the diet is restricted | |
| 54. |
Enzyme required to convert polypeptides to amino acids is |
| A. | pepsin |
| B. | maltase |
| C. | erepsin |
| D. | diastase |
| Answer» D. diastase | |
| 55. |
Which of the following statements is true about SDS polyacrylamide chromatography? |
| A. | SDS polyacrylamide gel electrophoresis separates proteins on the basis of size |
| B. | SDS polyacrylamide gel electrophoresis separates proteins on the basis of charge |
| C. | SDS binds to proteins non-covalently with a stoichiometry of around one SDS molecule per three amino acids |
| D. | SDS binds to proteins non-covalently with a stoichiometry of around one SDS molecule per one amino acid |
| Answer» C. SDS binds to proteins non-covalently with a stoichiometry of around one SDS molecule per three amino acids | |
| 56. |
Immunoaffinity chromatography can be used in biochemical applications to |
| A. | break down antibody structure |
| B. | purify protein antigen |
| C. | break down antigen and analyze quantitatively |
| D. | none of the above |
| Answer» C. break down antigen and analyze quantitatively | |
| 57. |
The peptide, Val-Lys-Glu-Met-Ser-Trp-Arg-Ala, was digested with cyanogen bromide (CNBr) 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» D. Val-Lys-Glu + Met-Ser-Trp-Arg-Ala | |
| 58. |
Since ΔG° = -RTlnK |
| A. | a 10-fold increase in K decreases ΔG° by about 10-fold |
| B. | a 10-fold decrease in K decreases ΔG° by about 2.3*RT |
| C. | a 10-fold increase in K decreases ΔG° by about 2.3*RT |
| D. | a 10-fold decrease in K increases ΔG° by about 10-fold |
| Answer» D. a 10-fold decrease in K increases ΔG° by about 10-fold | |
| 59. |
The resonance structures that can be drawn for the peptide bond indicate that the peptide bond |
| A. | is stronger than an ordinary single bond |
| B. | has partial double bond character |
| C. | both (a) and (b) |
| D. | is still not completely understood |
| Answer» D. is still not completely understood | |
| 60. |
Which hemoglobin chain replaces the beta chain in embryonic hemoglobulin? |
| A. | Delta |
| B. | Epsilon |
| C. | Gamma |
| D. | Alfa |
| Answer» C. Gamma | |
| 61. |
The amino acids used to build proteins in cells can be distinguished through |
| A. | C-OH side chain |
| B. | C=O bonding |
| C. | side chain of R groups |
| D. | C-H chain |
| Answer» D. C-H chain | |
| 62. |
For the unfolding reaction of Protein G, ΔH° =210.6 kJ/mol, this means that |
| A. | unfolding is favored enthalpically |
| B. | folding is favored enthalpically |
| C. | the entropy is positive at all temperatures |
| D. | the entropy is negative at all temperatures |
| Answer» C. the entropy is positive at all temperatures | |
| 63. |
In Counter immunoelectrophoresis |
| A. | electrophoresis will drive the antibody and antigen parallel to each other |
| B. | electrophoresis will drive the antibody and antigen toward each other |
| C. | the antibody will migrate towards anode |
| D. | the antibody will migrate towards cathode |
| Answer» C. the antibody will migrate towards anode | |
| 64. |
A protein that shows infinite cooperative for binding of n ligands will |
| A. | show a Hill coefficient (nH) of 0.0 |
| B. | only be found in either the unliganded form or the fully liganded form |
| C. | show a Hill coefficient (nH) of n |
| D. | both (b) and (c) |
| Answer» E. | |
| 65. |
Secondary structure in protein refers to |
| A. | linear sequence of amino acids joined together by peptide bond |
| B. | three dimensional arrangement of all amino acids in polypeptide chain |
| C. | regular folding of regions of the polypeptide chain |
| D. | protein made up of more than one polypeptide chain |
| Answer» D. protein made up of more than one polypeptide chain | |
| 66. |
Reactions of condensation produce polymers e.g. |
| A. | peptides |
| B. | proteins |
| C. | carbonyls |
| D. | hydrocarbons |
| Answer» C. carbonyls | |
| 67. |
When a small number of acids or bases are added to zwitterion ion, it resists a change in |
| A. | temperature |
| B. | volatility |
| C. | polarity |
| D. | pH |
| Answer» E. | |
| 68. |
The number of amino acids by which human proteins are manufactured is |
| A. | twenty |
| B. | forty |
| C. | twelve |
| D. | eight |
| Answer» B. forty | |
| 69. |
The general formula for 2 amino carboxylic acid is |
| A. | R-CH(NH₂)COOH |
| B. | R-CHCOOH |
| C. | R-CH(NH₂) |
| D. | R-CH |
| Answer» B. R-CHCOOH | |
| 70. |
The amino acid sequences of thousands of different proteins from many species have been determined using principles first developed by? |
| A. | Edman |
| B. | Sanger |
| C. | Mendel |
| D. | Watson and Crick |
| Answer» C. Mendel | |
| 71. |
Metastasis involves |
| A. | ability of cells to dissolve cellular matrix |
| B. | metalloprotein levels |
| C. | decreased levels of proteins that regulate metalloproteins |
| D. | all of the above |
| Answer» E. | |
| 72. |
Amino acids are by nature |
| A. | acidic |
| B. | basic |
| C. | amphoteric |
| D. | alkalinic |
| Answer» D. alkalinic | |
| 73. |
Proteins are separated in an SDS-PAGE experiment on the basis of their |
| A. | positively charged side chains |
| B. | molecular weight |
| C. | negatively charged side chains |
| D. | different isoelectric points |
| Answer» C. negatively charged side chains | |
| 74. |
Peptides in the fully extended chain conformation |
| A. | have Y = F = 180° |
| B. | do not occur in nature |
| C. | also have a cis geometry in their peptide bonds |
| D. | are equivalent to the (3-sheet structure |
| Answer» B. do not occur in nature | |
| 75. |
Which of the following statements is true about ion-exchange chromatography? |
| A. | It separates proteins according to their size |
| B. | The column matrix with bound anionic groups is called cationic exchanger |
| C. | The column matrix with bound anionic groups is called anionic exchanger |
| D. | The column matrix with bound cationic groups is called cationic exchanger |
| Answer» C. The column matrix with bound anionic groups is called anionic exchanger | |
| 76. |
What is the effect of a decrease in pH on hemoglobin oxygen affinity? |
| A. | Decrease in oxygen affinity |
| B. | Increase in oxygen affinity |
| C. | No effect on oxygen affinity |
| D. | Increase affinity in muscle cell otherwise decrease |
| Answer» B. Increase in oxygen affinity | |
| 77. |
If pK1 = 2.34 and pK2 = 9.60, then the isoelectric point pI is? |
| A. | 5.87 |
| B. | 5.97 |
| C. | 3.67 |
| D. | 11.94 |
| Answer» C. 3.67 | |
| 78. |
The two amino acids having R groups with a negative net charge at pH 7.0 are ___________ |
| A. | Aspartate and glutamate |
| B. | Arginine and histidine |
| C. | Cysteine and methionine |
| D. | Proline and valine |
| Answer» B. Arginine and histidine | |
| 79. |
Polypeptides bear long molecules hence they are represented shorthand by |
| A. | three letter abbreviation |
| B. | numerals |
| C. | Roman numbers |
| D. | two letter abbreviations |
| Answer» B. numerals | |
| 80. |
Number of chiral centers in isoleucine is? |
| A. | 1 |
| B. | 2 |
| C. | 3 |
| D. | 4 |
| Answer» C. 3 | |
| 81. |
Agarose gel electrophoresis and pulsed field gel electrophoresis may be used to resolve respectively |
| A. | 2000 kb and 20kb DNA |
| B. | 1000 kb and l0kb DNA |
| C. | 20 kb and 2000 kb DNA |
| D. | 10 kb and 1000 kb DNA |
| Answer» D. 10 kb and 1000 kb DNA | |
| 82. |
Product formed after reaction between two amino acids is called |
| A. | reagent |
| B. | peptide |
| C. | dipeptide |
| D. | poly peptide |
| Answer» D. poly peptide | |
| 83. |
What is the proportion of glycine residues in collagenous regions? |
| A. | One-fourth |
| B. | One-third |
| C. | Half |
| D. | One-tenth |
| Answer» C. Half | |
| 84. |
In an SDS-PAGE |
| A. | proteins are denatured by the SDS |
| B. | proteins have the same charge-to-mass ratio |
| C. | smaller proteins migrate more rapidly through the gel |
| D. | all of the above |
| Answer» E. | |
| 85. |
Glycine which is a simplest amino acid is |
| A. | amino acid |
| B. | amino ethanoic acid |
| C. | aminate |
| D. | amylase |
| Answer» C. aminate | |
| 86. |
Which of the following is an example of tertiary structure in a protein? |
| A. | A multimeric protein |
| B. | An a-helix |
| C. | A P-pleated sheet |
| D. | A globular domain |
| Answer» E. | |
| 87. |
Who deduced the double-helical structure of DNA? |
| A. | Frederick Sanger |
| B. | Mendel |
| C. | Watson and Francis Crick |
| D. | Anton van Leeuwenhoek |
| Answer» D. Anton van Leeuwenhoek | |
| 88. |
Protein folding is |
| A. | automatic, mediated by the protein itself |
| B. | mediated by other proteins called chaperones |
| C. | mediated by the ribosomes |
| D. | none of the above |
| Answer» C. mediated by the ribosomes | |
| 89. |
The four subunits of the hemoglobin (Hb) gene represent protein's |
| A. | primary structure |
| B. | secondary structure |
| C. | tertiary structure |
| D. | quaternary structure |
| Answer» E. | |
| 90. |
The nature of peptide bond can be best explained as |
| A. | partial double bond |
| B. | truly double bond |
| C. | Hydrogen bond |
| D. | Van der waals force |
| Answer» B. truly double bond | |
| 91. |
Heme is the binding pocket of myoglobin and hemoglobin and is composed of |
| A. | negatively charged residues |
| B. | polar residues |
| C. | hydrophobic residues |
| D. | positively charged residues |
| Answer» D. positively charged residues | |
| 92. |
Immunoelectrophoresis techniques are designed to separate the mixture components from each other by using electrophoresis |
| A. | prior to reaction with antibody |
| B. | prior to reaction with antigen |
| C. | after reaction with antibody |
| D. | after reaction with antigen |
| Answer» B. prior to reaction with antigen | |
| 93. |
The correlation between free energy ΔG transfer between the aqueous/organic phases and the surface area of amino acid residues |
| A. | reflects the reduction in solvent-accessible area during protein folding |
| B. | is only meaningful for the polar amino acids |
| C. | ignores the important contribution of the peptide bond |
| D. | is similar to effects seen with SDS denaturation |
| Answer» B. is only meaningful for the polar amino acids | |
| 94. |
Which of the following statements is true about two-dimensional electrophoresis? |
| A. | Separates proteins of identical molecular weight, same pI but different charge |
| B. | Separates proteins of different molecular weight and different pI |
| C. | Separates proteins of identical molecular weight that differ in pI |
| D. | Isoelectric focusing is also termed as two-dimensional electrophoresis |
| Answer» D. Isoelectric focusing is also termed as two-dimensional electrophoresis | |
| 95. |
Tertiary conformation of proteins is maintained by 3 types of bonds namely ionic, hydrogen and __________ |
| A. | Sulfide |
| B. | Disulfide |
| C. | Covalent |
| D. | Peptide |
| Answer» C. Covalent | |
| 96. |
At the midpoint of a temperature transition curve, |
| A. | half of the protein is denatured |
| B. | Keq = 1.0 and ΔG = 0 |
| C. | [Native] = [Unfolded] |
| D. | All of these |
| Answer» E. | |
| 97. |
Which among the following is a non-essential amino acid? |
| A. | Serine |
| B. | Threonine |
| C. | Lysine |
| D. | Histidine |
| Answer» B. Threonine | |
| 98. |
The competitive immunoassay can be used |
| A. | to detect very small amounts of antigen |
| B. | to detect antibody associated with allergies (IgE) |
| C. | both (a) and (b) |
| D. | commonly to detect trace amounts of drugs. |
| Answer» D. commonly to detect trace amounts of drugs. | |
| 99. |
Which of the three subunits of the G proteins binds GDP and GTP? |
| A. | Alpha |
| B. | Beta |
| C. | Gamma |
| D. | Delta |
| Answer» B. Beta | |
| 100. |
Zwitterion ions are |
| A. | crystalline solid |
| B. | soluble in water |
| C. | amphoteric |
| D. | all of above |
| Answer» E. | |