This set of Enzyme Technology Multiple Choice Questions & Answers (MCQs) focuses on “Enzyme Kinetics Fundamentals – Enzyme Nomenclature – 1”.
1. Which of the following rule was not given by the enzyme commission?
a) Assigned each enzyme a name
b) Assigned each enzyme a 4-digit code
c) Divided enzymes into 6 main groups
d) Mention of cofactors
View Answer
Explanation: Cofactor is the non-protein component of the enzyme. The enzyme commission was appointed by the International Union of Biochemistry. The enzyme commission was designed only for enzymes and it stated that each enzyme is given a name and a 4-digit code. It also divided the enzymes into 6 main groups based on the reactions they catalyzed.
2. Enzymes that catalyze the transfer of atom or group between two molecules is known as __________
a) oxidoreductases
b) transferases
c) ligases
d) isomerases
View Answer
Explanation: Transferases catalyze the transfer of atoms such as acyl-, alkyl-, and glycosyl groups. Oxidoreductases catalyzes redox reactions, whereas ligases catalyze the formation of covalent bonds coupled with breakdown of ATP or other NTPs. Isomerases catalyzes formation of isomers of molecules.
3. Pectinases belong to which class of enzyme?
a) Ligases
b) Hydrolases
c) Lyases
d) Transferases
View Answer
Explanation: Pectinases belong to class of Lyases which are involved in the elimination reaction resulting in removal of group of atoms from the substrate molecule. Ligases are involved in synthesis reactions and hydrolases in hydrolytic reactions. Transferases involve the transfer of atoms from the substrate.
4. In this below equation, Enzyme Y belongs to which class of enzymes?
A-X + H2O \(_{\overrightarrow{Enzyme \,Y}}\) X-OH + AH
a) Peroxidase
b) Hydrolases
c) Pectinase
d) Aldolase
View Answer
Explanation: It’s a hydrolytic reaction wherein water molecules are involved and they break the bond of the substrate and form hydroxyl group compounds. Peroxidases, Pectinases and aldolase does not belong to main class of enzymes given by enzyme commission. Peroxidase belongs to oxidoreductase, whereas pectinase and aldolase belong to lyases.
5. Glycosidases, lipases and proteases belong to which class of enzymes?
a) Hydrolases
b) Ligases
c) Isomerases
d) Transferases
View Answer
Explanation: Glycosidases, lipases and proteases belong to hydrolases. This class of enzymes catalyze the hydrolytic reaction and their reversal. Ligases are involved in ligation reactions whereas transferases involve transfer of atoms. Isomerases are class of enzymes that are involved in isomerization of molecules.
6. Which of the following belongs to the class of isomerases?
a) Aldolases
b) Oxygenases
c) Epimerases
d) Esterases
View Answer
Explanation: Isomerases involves the catalysis of isomerization reaction. Isomerase includes epimerase, racemase and intramolecular transferase. Hence Epimerase belongs to isomerase class of enzymes. Aldolase belongs to lyases whereas oxygenases belongs to oxidoreductases. Esterases belong to the hydrolases class of enzymes.
7. In the following diagram, what does enzyme Z represent?
a) Hydrolases
b) Ligases
c) Aldolases
d) Glucose isomerase
View Answer
Explanation: In the above diagram, a new product synthesis is showed by forming new bonds between two substrates, coupled to breakdown of ATP. The above reaction is said to be ligation reaction that involves ligase class of enzymes as catalysts. Glucose isomerase, as the name suggest are involved in isomerization reactions. As compared to Aldolases, which belong to class of lyases and Hydrolases are involved in hydrolytic reactions.
8. Which of the following is an example for Oxidoreductases?
a) Glucose oxidase
b) Glutathione synthetase
c) Aspartate aminotransferase
d) Histidase
View Answer
Explanation: As glucose oxidases transfers electrons from glucose to oxygen atoms (redox reaction), it is an example of oxidoreductases. Glutathione synthetase is an example of ligases as this enzyme is involved in synthesis of new products. Aspartate aminotransferase transfers amino group from aspartate forming glutamate, and hence it is an example of transferase class of enzymes. Histidase is involved in removal of amino group from histidine. Thus, histidase is an example of lyases.
9. Histidase: Lyases :: Chymosin: ___________
a) Ligases
b) Isomerases
c) Hydrolases
d) Transferases
View Answer
Explanation: Histidase is an example for lyase class of enzymes which are involved in elimination reactions. In similar way chymosin is an example for hydrolases which are involved in hydrolysis of the substrate. Chymosin is also called as renin. Examples of ligases, isomerases and transferases are glutathione synthetase, glucose isomerase and aspartate aminotransferase respectively.
Sanfoundry Global Education & Learning Series – Enzyme Technology.
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