MCQOPTIONS
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MCQOPTIONS
This section includes 94 Mcqs, each offering curated multiple-choice questions to sharpen your Biochemistry knowledge and support exam preparation. Choose a topic below to get started.
| 51. |
Why is it generally preferable to use absorbance as a measure of absorption rather than % transmittance? |
| A. | Because %T cannot be measured as accurately as absorbance |
| B. | Because %T is dependant on the power of the incident radiation |
| C. | Because absorbance is proportional to the concentration of the analyte, whereas %T is not |
| D. | none of the above |
| Answer» D. none of the above | |
| 52. |
In reversed phase HPLC, there is a |
| A. | non polar solvent/polar column |
| B. | polar solvent/non-polar column |
| C. | non polar solvent/non-polar column |
| D. | any of the above |
| Answer» C. non polar solvent/non-polar column | |
| 53. |
Which of the following statements is true for a refractive index detector in HPLC? |
| A. | It is more sensitive than a UV detector |
| B. | It can only be used for isocratic elutions |
| C. | It does not respond to many solutes |
| D. | none of above |
| Answer» D. none of above | |
| 54. |
A gradient elution in HPLC is one in which the composition of the solvent |
| A. | remains constant |
| B. | is changed continuously or in a series of steps |
| C. | both (a) and (b) |
| D. | none of the above |
| Answer» C. both (a) and (b) | |
| 55. |
HPLC stands for |
| A. | High Pressure Liquid Chromatography |
| B. | High Performance Liquid Chromatography |
| C. | both (a) and (b) |
| D. | Highly Placed Liquid Chromatography |
| Answer» D. Highly Placed Liquid Chromatography | |
| 56. |
The eluent strength is a measure of |
| A. | solvent adsorption energy |
| B. | solvent absorption energy |
| C. | solvent diffusivity |
| D. | solvent mixing index |
| Answer» B. solvent absorption energy | |
| 57. |
Column efficiency is measured in terms of number of plates which is |
| A. | inversely related to the square of the peak width |
| B. | directly related to the square of the peak width |
| C. | inversely related to the cube root of the peak width |
| D. | directly related to the square of the peak width |
| Answer» B. directly related to the square of the peak width | |
| 58. |
For a typical adsorbent such as silica gel, the most popular pore diameters are |
| A. | 10 and 50 A° |
| B. | 60 and 100 A° |
| C. | 100 and 150 A° |
| D. | 150 and 200 A° |
| Answer» C. 100 and 150 A° | |
| 59. |
In reverse phase chromatography, the stationary phase is made |
| A. | non-polar |
| B. | polar |
| C. | either non-polar or polar |
| D. | none of these |
| Answer» B. polar | |
| 60. |
Ion exchange chromatography is based on the |
| A. | electrostatic attraction |
| B. | electrical mobility of ionic species |
| C. | adsorption chromatography |
| D. | partition chromatography |
| Answer» B. electrical mobility of ionic species | |
| 61. |
The general expression for the appearance of a solute in an effluent is (where V is the elution volume of a substance , V0 void volume, kD distribution constant and Vi internal water volume) |
| A. | V = V0 + kDVi |
| B. | V = V0/Vi |
| C. | V = V0 - kDVi |
| D. | V/V0 = kDVi |
| Answer» B. V = V0/Vi | |
| 62. |
A combination of paper chromatography and electrophoresis involves |
| A. | partition chromatography |
| B. | electrical mobility of the ionic species |
| C. | both (a) and (b) |
| D. | none of these |
| Answer» D. none of these | |
| 63. |
Better understanding of the nuclei is possible, |
| A. | with the help of wavelength spectrum |
| B. | with the help of frequencies ranges |
| C. | with the help of a mathematical translator called the fourier transfer algorithm |
| D. | none of the above |
| Answer» D. none of the above | |
| 64. |
In gas chromatography, the basis for separation of the components of the volatile material is the difference in |
| A. | partition coefficients |
| B. | conductivity |
| C. | molecular weight |
| D. | molarity |
| Answer» B. conductivity | |
| 65. |
What is used to cool the superconducting coil? |
| A. | Hydrogen |
| B. | Ice |
| C. | Dry ice |
| D. | Liquid helium |
| Answer» E. | |
| 66. |
When placed in a magnetic field, all the random spins of the nuclei |
| A. | stop |
| B. | reverse direction |
| C. | align with the magnetic field |
| D. | rotate to 90° away from the induced field |
| Answer» D. rotate to 90° away from the induced field | |
| 67. |
Coupling causes the peaks in 1H NMR spectra to be split into |
| A. | two peaks |
| B. | multiple peaks equal to the number of hydrogens on surrounding atoms |
| C. | multiple peaks equal to the number of surrounding carbon atoms |
| D. | multiple peaks equal to the number of hydrogen on surrounding atoms, plus one |
| Answer» E. | |
| 68. |
Which of the statements is correct? |
| A. | Gas chromatography is used to analyse gases |
| B. | Gas chromatography is used to analyse solids |
| C. | Gas chromatography is used to analyse gases, solutions and solids |
| D. | All of the above |
| Answer» E. | |
| 69. |
All hydrogen atoms |
| A. | have the same resonance frequency |
| B. | resonate at different frequencies depending on their environment. |
| C. | are attached to carbon |
| D. | resonate at about the same frequency as carbon |
| Answer» C. are attached to carbon | |
| 70. |
Why is it important to use a deuterated solvent? |
| A. | NMR uses least of this solvent |
| B. | So the spectrometer can lock onto the sample to prevent the spectrum from drifting during aquisition |
| C. | Expensive solvents work best with NMR |
| D. | They dissolve polymer the fastest |
| Answer» C. Expensive solvents work best with NMR | |
| 71. |
Which of the following gases is unsuitable for use as a GC carrier gas? |
| A. | Nitrogen |
| B. | Helium |
| C. | Oxygen |
| D. | All of the above |
| Answer» D. All of the above | |
| 72. |
What does the selectivity factor describe? |
| A. | The proportional difference in widths of two chromatographic peaks |
| B. | The maximum number of different species which a column can separate simultaneously |
| C. | The relative separation achieved between two species |
| D. | None of the above |
| Answer» D. None of the above | |
| 73. |
What is the relationship between wavelength and wave number? |
| A. | Wavenumber = 1 / wavelength in centimeters |
| B. | Wavenumber - wavelength in nanometers = 1 |
| C. | Wavelength in nanometers x wavenumber = 1 |
| D. | None of the above |
| Answer» B. Wavenumber - wavelength in nanometers = 1 | |
| 74. |
The sequence of amino acids in proteins can be determined by means of |
| A. | identification of the -NH₂ terminal amino acids |
| B. | identification of the -COOH terminal amino acids |
| C. | partial cleavage of the original polypeptide into smaller polypeptides |
| D. | all of the above |
| Answer» E. | |
| 75. |
What does the Michelson interferometer do? |
| A. | Split a polychromatic beam of radiation into its component wavelengths |
| B. | Selectively filter certain wavelengths from a beam of I.R. radiation |
| C. | Modulate the I.R. signal at a lower frequency, so that it can be observed by a detector |
| D. | none of the above |
| Answer» D. none of the above | |
| 76. |
The GC trace obtained after an experiment is called a |
| A. | chromatograph |
| B. | chromatogram |
| C. | chromatophore |
| D. | graph |
| Answer» C. chromatophore | |
| 77. |
Molar absorbtivity is the measure of the |
| A. | amount of light absorbed per unit length |
| B. | amount of light absorbed per unit concentration |
| C. | amount of light reflected and absorbed per unit concentration |
| D. | None of the above |
| Answer» C. amount of light reflected and absorbed per unit concentration | |
| 78. |
An eluotropic series |
| A. | ranks solvents by their relative abilities to displace solutes from a given absorbent |
| B. | ranks column packing material by their relative abilities to retain solutes on the column |
| C. | is a measure of the solvent adsorption energy |
| D. | none of the above |
| Answer» B. ranks column packing material by their relative abilities to retain solutes on the column | |
| 79. |
The column is heated to |
| A. | prevent analyte condensation within the column |
| B. | control elution of the different analytes |
| C. | reduce band broadening to get sharper peaks |
| D. | all of these |
| Answer» E. | |
| 80. |
What is shielding in NMR? |
| A. | Using a curved piece of metal to block an opponents attack |
| B. | Putting metal around an Rf source |
| C. | When the magnetic moment of an atom blocks the full induced magnetic field from surrounding nuclei |
| D. | Blocking parts of a molecule from Rf radiation |
| Answer» D. Blocking parts of a molecule from Rf radiation | |
| 81. |
How many possible orientations do spin 1/2 nuclei have when they are located in an applied magnetic field? |
| A. | 2 |
| B. | 4 |
| C. | 3 |
| D. | 6 |
| Answer» B. 4 | |
| 82. |
Derivatisation of a sample is carried out to |
| A. | reduce polarity of the analytes |
| B. | increase the detector response |
| C. | increase volatility of the analytes |
| D. | all of the above |
| Answer» E. | |
| 83. |
Which of the following(s) is/are the advantage of HPLC over traditional LPLC (low-pressure liquid chromatography)? |
| A. | Greater sensitivity and reusable columns |
| B. | Ideal for ionic species and large molecules |
| C. | Sample recovery |
| D. | All of the above |
| Answer» E. | |
| 84. |
HPLC methods include |
| A. | liquid/liquid (partition) chromatography |
| B. | liquid/solid (adsorption) chromatography |
| C. | ion exchange and size exclusion chromatography |
| D. | all of the above |
| Answer» E. | |
| 85. |
What does the retention factor, k', describe? |
| A. | The distribution of an analyte between the stationary and the mobile phase |
| B. | The migration rate of an analyte through a column |
| C. | The velocity of the mobile phase |
| D. | All of these |
| Answer» C. The velocity of the mobile phase | |
| 86. |
An isocratic elution in HPLC is one in which the composition of the solvent |
| A. | remains constant |
| B. | changes continuously |
| C. | changes in a series of steps |
| D. | none of these |
| Answer» B. changes continuously | |
| 87. |
Which of the following detectors give mass flow-dependent signals? |
| A. | Electron capture detector |
| B. | Field ionisation detector |
| C. | Thermal conductivity detector |
| D. | All of the above |
| Answer» C. Thermal conductivity detector | |
| 88. |
Headspace analysis is carried out in order to |
| A. | analyse volatile compounds from solid or liquid samples |
| B. | determine the psychological state of the tutor |
| C. | analyse the column contents ahead of the sample |
| D. | determine non-volatiles |
| Answer» B. determine the psychological state of the tutor | |
| 89. |
Split injection is carried out by |
| A. | splitting the sample into smaller portions to inject sequentially |
| B. | splitting the sample into smaller portions to inject at the same time through parallel ports |
| C. | splitting off some of the sample so that it does not enter the column |
| D. | none of the above |
| Answer» D. none of the above | |
| 90. |
Vibrational spectroscopy is |
| A. | a large mass on a weak spring |
| B. | a flashlight through a prism and shake it |
| C. | a class of spectroscopic techniques which analyzes molecular motions |
| D. | an Infrared spectroscopy |
| Answer» D. an Infrared spectroscopy | |
| 91. |
A simple harmonic oscillator may absorb energy |
| A. | at anytime. |
| B. | when the frequencies match exactly |
| C. | when the amplitudes are the same. |
| D. | at no time. |
| Answer» C. when the amplitudes are the same. | |
| 92. |
Why are rotational transitions of little use to a spectroscopist? |
| A. | Because the energy required to induce a rotational transition is so small that it cannot be measured |
| B. | Because rotational transitions are extremely rare |
| C. | Because, in liquids and solids, spectral lines corresponding to rotational transitions are broadened as the result of molecular collisions and other interactions |
| D. | All of the above |
| Answer» D. All of the above | |
| 93. |
UV-Vis spectroscopy of organic compounds is usually concerned with which electronic transition(s)? |
| A. | σ → σ* |
| B. | n → σ* |
| C. | n → π* and π → π* |
| D. | none of these |
| Answer» D. none of these | |
| 94. |
Which of the following components of a monochromator is the dispersing element? |
| A. | The collimating lens |
| B. | The entrance slit |
| C. | The diffraction grating |
| D. | None of these |
| Answer» D. None of these | |