McqMate
These multiple-choice questions (MCQs) are designed to enhance your knowledge and understanding in the following areas: Uncategorized topics .
| 101. |
Which of the following is not a characteristic of a catalyst? |
| A. | it participates in the reaction |
| B. | it enhances the equilibrium rate |
| C. | it activates equilibrium |
| D. | it initialises the reaction |
| Answer» A. it participates in the reaction | |
| Explanation: the main purpose of using a catalyst is only to increase the rate of achieving the equilibrium state in case of slow reaction. other than that it will not initiate or involve in the reaction. | |
| 102. |
Which of the following will decrease the rate of reaction? |
| A. | catalytic poison |
| B. | positive catalyst |
| C. | negative catalyst |
| D. | catalytic promoters |
| Answer» A. catalytic poison | |
| Explanation: catalytic poisons are the once which are used to slow down the reaction inorder to avoid explosion when the temperature or pressure increase the critical value. hence catalytic poisons are used such as aluminium oxide. | |
| 103. |
Which of the following is a catalytic poison? |
| A. | potassium nitrate |
| B. | aluminium nitrate |
| C. | aluminium oxide |
| D. | chlorine |
| Answer» C. aluminium oxide | |
| Explanation: aluminium oxide is known for its sophisticated properties and is mainly used in the process of corrosion preventing it absorbs moisture and has high retentivity and hence is used as a catalytic poison. | |
| 104. |
Which of the following is used as a catalytic promoter? |
| A. | chlorine |
| B. | nitrate |
| C. | bromine |
| D. | helium |
| Answer» B. nitrate | |
| Explanation: the use of a promoter is to increase the rate of equilibrium. we know that nitrogen has promoting properties in the case of nitrate molecules. thus the can act as good promoters in reaction. | |
| 105. |
Where is the intermediate theory used? |
| A. | heterogeneous components |
| B. | homogeneous components |
| C. | miscible components |
| D. | immiscible components |
| Answer» A. heterogeneous components | |
| Explanation: intermediate theory is the process in which an intermediate product is formed and hence it is suitable for homogeneous components and not for heterogeneous components. | |
| 106. |
Lambda PL promoter is used in which vectors? |
| A. | cloning vectors |
| B. | expression vectors |
| C. | both cloning and expression vectors |
| D. | bacteriophage mu |
| Answer» B. expression vectors | |
| Explanation: lambda pl promoters are the promoters for the left region in bacteriophage lambda. it is widely used in expression vectors. | |
| 107. |
The promoter can be controlled by a repressor which is temperature sensitive. |
| A. | true |
| B. | false |
| Answer» A. true | |
| Explanation: the promoter is activated at a temperature higher than 30 degrees because at this temperature repressor is inactivated. | |
| 108. |
The operon encodes proteins involved in arabinose metabolism. |
| A. | arabcd |
| B. | araabd |
| C. | arabad |
| D. | aradba |
| Answer» C. arabad | |
| Explanation: the arabad operon encodes proteins involved in arabinose metabolism. it is controlled by arac transcriptional regulator. | |
| 109. |
tac promoter is an example of which type of promoter? |
| A. | hybrid promoter |
| B. | fusion promoter |
| C. | lacz promoter |
| D. | arabad promoter |
| Answer» A. hybrid promoter | |
| Explanation: hybrid promoters are those promoters which are produced by two promoters from different sources. tac promoter is a hybrid promoter produced from trp promoter and lacuv5 promoter. | |
| 110. |
The tac promoter is made by region of trp promoter and region of the lacUV5 promoter. |
| A. | 10, 35 |
| B. | 35, 10 |
| C. | 10, 10 |
| D. | 35, 35 |
| Answer» B. 35, 10 | |
| Explanation: it is a hybrid promoter made by 35 regions of trp promoter and 10 regions of the lacuv5 promoter. | |
| 111. |
The tac promoter includes the lac operator and is regulated by a repressor. |
| A. | true |
| B. | false |
| Answer» A. true | |
| Explanation: the tac promoter includes the lac operator and is regulated by the repressor. the repressor is to be supplied by the host. | |
| 112. |
Expression of T7 promoter- lac operator hybrid requires |
| A. | t7 rna polymerase |
| B. | an inducer such as iptg |
| C. | both t7 rna polymerase and inducer such as iptg |
| D. | t7 dna polymerase |
| Answer» C. both t7 rna polymerase and inducer such as iptg | |
| Explanation: expression of t7 promoter- lac operator hybrid requires both t7 rna polymerase and inducer such as iptg. if inducer is absent levels of expression are very low. | |
| 113. |
When lacUV5 control system is used, addition of IPTG the expression of |
| A. | activates, t7 rna polymerase |
| B. | inactivates, t7 rna polymerase |
| C. | activates, t7 dna polymerase |
| D. | inactivates, t7 dna polymerase |
| Answer» A. activates, t7 rna polymerase | |
| Explanation: when a lacuv5 control system is used, the addition of iptg activates the expression of t7 rna polymerase. thus transcription of sequences under the control of t7 promoter is controlled. | |
| 114. |
A is a biocatalyst that increases the rate of the reaction without being changed. |
| A. | aluminum oxide |
| B. | silicon dioxide |
| C. | enzyme |
| D. | hydrogen peroxide |
| Answer» C. enzyme | |
| Explanation: among these options, an enzyme is an only option which is a biocatalyst that catalyzes the chemical reaction without being changed while all other options are of the catalyst which increases or decrease the rate of reaction based on their concentration. | |
| 115. |
Enzyme increases the rate of reaction by lowering the activation energy. |
| A. | true |
| B. | false |
| Answer» A. true | |
| Explanation: activation energy is the difference in free energy between the reactants and transition state. to complete a reaction, enzyme lowers the activation energy and crosses the transition state. | |
| 116. |
What is the nature of an enzyme? |
| A. | vitamin |
| B. | lipid |
| C. | carbohydrate |
| D. | protein |
| Answer» D. protein | |
| Explanation: all enzymes are protein except catalytic rna molecule. the native protein conformation of an enzyme defines its catalytic activity. once the enzyme is denatured, its catalytic activity is also lost. | |
| 117. |
What is an apoenzyme? |
| A. | it is a protein portion of an enzyme |
| B. | it is a non-protein group |
| C. | it is a complete, biologically active conjugated enzyme |
| D. | it is a prosthetic group |
| Answer» A. it is a protein portion of an enzyme | |
| Explanation: removal of cofactor from a conjugated enzymes forms apoenzyme which is a protein component. a cofactor is a non- protein group while a complete conjugated enzyme is known as a holoenzyme. | |
| 118. |
Name the coenzyme of riboflavin (B2)? |
| A. | nad or nadp |
| B. | fad and fmn |
| C. | coenzyme a |
| D. | thiamine pyrophosphate |
| Answer» B. fad and fmn | |
| Explanation: riboflavin is a part of vitamin b complex, its coenzyme form is a fad (flavin adenine dinucleotide) which involves a redox reaction. nad is a coenzyme form of nicotinic acid, and thiamine pyrophosphate is a coenzyme of thiamine. | |
| 119. |
Which of this vitamin is associated with the coenzyme Biocytin? |
| A. | nicotinic acid |
| B. | thiamine |
| C. | biotin |
| D. | pyridoxine |
| Answer» C. biotin | |
| Explanation: biocytin is a coenzyme of biotin which involves in carboxylation reaction while thiamine takes part in decarboxylation reaction. | |
| 120. |
Name the enzyme secreted by pancreas? |
| A. | pepsin |
| B. | chymotrypsin |
| C. | trypsin |
| D. | alcohol dehydrogenase |
| Answer» C. trypsin | |
| Explanation: trypsin is a proteolytic enzyme, secreted by the pancreas. it is one of the three digestive proteinases along with pepsin and chymotrypsin which breaks down dietary protein molecules into simpler forms. | |
| 121. |
Name the enzyme which catalyzes the oxidation-reduction reaction? |
| A. | transaminase |
| B. | glutamine synthetase |
| C. | phosphofructokinase |
| D. | oxidoreductase |
| Answer» D. oxidoreductase | |
| Explanation: oxidoreductase is a class of enzyme which catalyze the oxidation- reduction reaction. some of the oxidoreductase enzymes are oxidases, dehydrogenases, peroxidases etc. | |
| 122. |
What is the function of phosphorylase? |
| A. | transfer inorganic phosphate |
| B. | transfer a carboxylate group |
| C. | use h2o2 as the electron acceptor |
| D. | transfer amino group |
| Answer» A. transfer inorganic phosphate | |
| Explanation: phosphorylase is a transferase enzyme which involves a transfer of inorganic phosphate to a substrate while transcarboxylase transfer a carboxylate group and transaminase transfer amino group from amino acid to the keto acid. | |
| 123. |
Mark the CORRECT function of enzyme, Peptidase? |
| A. | cleave phosphodiester bond |
| B. | cleave amino bonds |
| C. | remove phosphate from a substrate |
| D. | removal of h2o |
| Answer» B. cleave amino bonds | |
| Explanation: hydrolases are the enzymes which cleave the bond by adding water. | |
| 124. |
Which of the following reaction is catalyzed by Lyase? |
| A. | breaking of bonds |
| B. | formation of bonds |
| C. | intramolecular rearrangement of bonds |
| D. | transfer of group from one molecule to another |
| Answer» A. breaking of bonds | |
| Explanation: lyase is the class of enzymes which does not involve hydrolysis or oxidation to break the bond. it catalyzes the breaking of c-c, c-o, c-n, c-s bonds by the process of elimination and results in the formation of a double bond. | |
| 125. |
Which of the following is true about Michaelis-Menten kinetics? |
| A. | km, the michaelis constant, is defined as that concentration of substrate at which enzyme is working at maximum velocity |
| B. | it describes single substrate enzymes |
| C. | km, the michaelis constant is defined as the dissociation constant of the enzyme- substrate complex |
| D. | it assumes covalent binding occurs between enzyme and substrate |
| Answer» B. it describes single substrate enzymes | |
| Explanation: km is defined as the concentration of substrate at which enzyme is working at half of maximum velocity. it is also a measure of the affinity that the enzyme has for its substrate. michaelis-menten kinetics assumes non-covalent binding between enzyme and substrate. | |
| 126. |
When the velocity of enzyme activity is plotted against substrate concentration, which of the following is obtained? |
| A. | hyperbolic curve |
| B. | parabola |
| C. | straight line with positive slope |
| D. | straight line with negative slope |
| Answer» A. hyperbolic curve | |
| Explanation: at low substrate concentration, the rate of a reaction is determined by the rate of formation of an enzyme-substrate complex. | |
| 127. |
Which of the following is an example for irreversible inhibitor? |
| A. | disulfiram |
| B. | oseltamivir |
| C. | protease inhibitors |
| D. | dipf |
| Answer» D. dipf | |
| Explanation: disulfiram, oseltamivir and protease inhibitors are reversible inhibitors. | |
| 128. |
Where does inhibitor binds on enzyme in mixed inhibition? |
| A. | at active site |
| B. | allosteric site |
| C. | does not bind on enzyme |
| D. | binds on substrate |
| Answer» B. allosteric site | |
| Explanation: the inhibitor binds at a place different from active site allosterically. | |
| 129. |
The catalytic efficiency of two distinct enzymes can be compared based on which of the following factor? |
| A. | km |
| B. | product formation |
| C. | size of the enzymes |
| D. | ph of optimum value |
| Answer» A. km | |
| Explanation: km is the substrate concentration. increased substrate concentration increases the rate of reaction. | |
| 130. |
What is the general mechanism of an enzyme? |
| A. | it acts by reducing the activation energy |
| B. | it acts by increasing the activation energy |
| C. | it acts by decreasing the ph |
| D. | it acts by increasing the ph |
| Answer» A. it acts by reducing the activation energy | |
| Explanation: for the reaction to occur at a faster rate, activation energy should be less. | |
| 131. |
What kind of steel requires definite amounts of other alloying elements? |
| A. | carbon steel |
| B. | alloying steel |
| C. | stainless steel |
| D. | tool steel |
| Answer» B. alloying steel | |
| Explanation: alloy steels are those steels which require a specific amount of the elements making up its composition. alloy steels consist of manganese, silicon, and copper as primary elements whose quantities are equal to or more than 1.65%, 0.60%, and 0.60% respectively. | |
| 132. |
Which of these is not a function of alloy steels? |
| A. | increases strength |
| B. | improves ductility |
| C. | reduces cost |
| D. | improves machinability |
| Answer» C. reduces cost | |
| Explanation: alloy steels are used to improve properties such as strength, hardness, ductility, grain structure, and machinability, among others. this, however, results in increased costs due to multiple elements involved in the process. | |
| 133. |
1 ALLOYS: INTRODUCTION- DEFINITION- PROPERTIES OF ALLOYS- SIGNIFICANCE OF ALLOYING, FUNCTIONS AND EFFECT OF ALLOYING ELEMENTS |
| A. | low alloy steels |
| B. | hsla steels |
| C. | high alloy steels |
| D. | stainless steels |
| Answer» A. low alloy steels | |
| Explanation: low alloy steels consist of 3% to 4% of alloying elements making up its composition. they have similar microstructure and heat treatments as plain carbon steels. hsla and aisi steels are the types of low alloy steels. | |
| 134. |
What does AISI steel stand for? |
| A. | american-indian steel institute |
| B. | american-indian society of iron |
| C. | american iron and steel institute |
| D. | alloys, iron and steel institute |
| Answer» C. american iron and steel institute | |
| Explanation: american iron and steel institute (aisi) is an association, established in america, which produces steel. aisi steels are used in machine construction. they are otherwise known as construction steels or structural steels. | |
| 135. |
Which of these is not an application of HSLA steels? |
| A. | bridges |
| B. | automobiles and trains |
| C. | building columns |
| D. | leaf and coil springs |
| Answer» D. leaf and coil springs | |
| Explanation: hsla steels are known as high-strength-low-alloy steels. these high strength steels are primarily used as structural materials or construction alloys. they are used to reduce weight on bridges, automobiles, pressure vessels, building columns, etc. | |
| 136. |
Steels containing more than 5% of one or more alloying elements are known as |
| A. | hsla steels |
| B. | high alloy steels |
| C. | tool and die steels |
| D. | stainless steels |
| Answer» B. high alloy steels | |
| Explanation: high alloy steels are composed of more than 5% of alloying elements. they have different microstructure and heat treatments than those of plain carbon steels. tool and die, and stainless steels are the types of high alloy steels. | |
| 137. |
Which of the following groups of alloying elements stabilize austenite? |
| A. | ni, mn, cu, and co |
| B. | cr, w, mo, v, and si |
| C. | cr, w, ti, mo, nb, v, and mn |
| D. | co, al, and ni |
| Answer» A. ni, mn, cu, and co | |
| Explanation: the alloying elements such as ni, mn, cu, and co have a tendency to alleviate austenite, whereas cr, w, mo, v, and si tend to stabilize ferrites. alloying elements such as cr, w, ti, mo, nb, v, and mn tend to form carbides. other elements like co, al, and ni help to weaken carbides and thereby form graphite. | |
| 138. |
Which family of steels are referred to as chromoly? |
| A. | 40xx |
| B. | 41xx |
| C. | 43xx |
| D. | 44xx |
| Answer» B. 41xx | |
| Explanation: the family of 41xx steel is usually called as chromoly or chrome-moly due to its primary alloying elements, chromium and molybdenum. steels such as 4130 and 4140 are generally used for bicycle frames, and as parts of firearms, flywheels etc. | |
| 139. |
What is the common name of COR-TEN steel? |
| A. | weathering steel |
| B. | control-rolled steel |
| C. | pearlite-reduced steel |
| D. | microalloyed steel |
| Answer» A. weathering steel | |
| Explanation: weathering steels are otherwise also known as cor-ten or corten steels. | |
| 140. |
Alloy steels containing 0.05% to 0.15% of alloying elements are called |
| A. | weathering steel |
| B. | stainless steel |
| C. | tool and die steel |
| D. | microalloyed steel |
| Answer» D. microalloyed steel | |
| Explanation: microalloyed steels contain alloying elements in small quantities (0.05% to 0.15%). these elements include niobium, vanadium, titanium, molybdenum, rare earth metals, among others. they are used to refine the microstructure of the grain or for precipitate hardening process. | |
| 141. |
Which is the primary element used for making stainless steel alloy? |
| A. | chromium |
| B. | zirconium |
| C. | vanadium |
| D. | indium |
| Answer» A. chromium | |
| Explanation: stainless steels contain iron and a minimum of 10.5% of chromium. this gives it great resistance to corrosion. | |
| 142. |
Addition of gives stainless steels an austenitic structure. |
| A. | molybdenum |
| B. | carbon |
| C. | nickel |
| D. | vanadium |
| Answer» C. nickel | |
| Explanation: nickel is added to stainless steels with a 3.5% to 22% composition to form austenitic structure. this results in the highest corrosion resistance among all stainless steels. they also possess high strength and ductility. | |
| 143. |
Stainless steels with little carbon and no nickel are called |
| A. | ferritic stainless steel |
| B. | austenitic stainless steel |
| C. | martensitic stainless steel |
| D. | duplex stainless steel |
| Answer» A. ferritic stainless steel | |
| Explanation: ferritic stainless steels are steels containing 12.5% to 17% of chromium. they are nickel¬-free and contain very little carbon making up its composition. they are, therefore, better resistant to corrosion than martensitic stainless steels. | |
| 144. |
Stainless steels with high strength, but low corrosion resistance are known as |
| A. | austenitic stainless steel |
| B. | ferritic stainless steel |
| C. | martensitic stainless steel |
| D. | duplex stainless steel |
| Answer» C. martensitic stainless steel | |
| Explanation: martensitic stainless steels are made of 12-14% chromium, along with molybdenum, nickel, and carbon. this makes the steels hard and brittle, but poorly resistant to corrosion. martensitic stainless steels are used in making swiss army knives. | |
| 145. |
Which of the following is not a type of oil- hardening steel? |
| A. | o1 |
| B. | o2 |
| C. | o6 |
| D. | o9 |
| Answer» D. o9 | |
| Explanation: oil hardening steels are a group of cold working tool steels. this group consists of o1 (0.9% c, 1% mn, 0.5% cr), | |
| 146. |
Mushet steel belongs to which group of tool steels? |
| A. | oil-hardening steels |
| B. | air-hardening steels |
| C. | high-speed steels |
| D. | hot-working steels |
| Answer» B. air-hardening steels | |
| Explanation: mushet steel was the first air- hardening tool steel. it belongs to the cold- working family of tool steels. it was developed by robert mushet. | |
| 147. |
What property does the AISI-SAE tool steel grade ‘L’ possess? |
| A. | cold-working |
| B. | hot-working |
| C. | plastic mild |
| D. | special purpose |
| Answer» D. special purpose | |
| Explanation: the steel grade ‘l’ refers to special purpose steel containing low alloy. it consists of elements such as carbon, chromium, manganese, and a few others. the l2 and l6 are the most commonly used steels under this category. | |
| 148. |
The low-carbon, high-alloyed steels which possess high strength and toughness are known as |
| A. | carbon steels |
| B. | alloy steels |
| C. | maraging steels |
| D. | stainless steels |
| Answer» C. maraging steels | |
| Explanation: maraging steels are those high strength steels which have tensile strengths up to 1900 mpa. they are composed of 18% ni, 7% co, and less than 0.05% c. | |
| 149. |
What do TRIP steels stand for? |
| A. | transformation induced porosity |
| B. | transformation induced plasticity |
| C. | transformation induced pearlite |
| D. | transformation induced property |
| Answer» B. transformation induced plasticity | |
| Explanation: trip steels are those steels containing high strength and ductility. they are mainly used for automotive industry needs. the expanded form of trip is transformation induced plasticity. it contains an austenite microstructure. | |
| 150. |
What is the maximum allowable temperature at which High-Speed Steels retain good cutting ability? |
| A. | 100oc |
| B. | 200oc |
| C. | 350oc |
| D. | 540oc |
| Answer» D. 540oc | |
| Explanation: high-speed steels have the ability to remove and cut metal at a much | |
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