1. Protein catalysts are called __________ and RNA catalysts are called _____________
a) enzymes, ribozymes
b) ribozymes, enzymes
c) enzymes, ribosomes
d) ribosomes, enzymes
Explanation: RNA catalysts are called ribozymes whereas protein catalysts are called enzymes. Most of the catalysts are enzymes made of proteins.
2. The non-protein constituents of conjugated proteins are called ___________?
a) enzymes
b) cofactors
c) amino acids
d) nucleosides
Explanation: The non-protein constituents of conjugated proteins (that act as enzymes) are called cofactors. These cofactors can be inorganic metals or organic coenzymes.
3. Enzymes have no effect on which of the following, in a chemical reaction?
a) activation energy
b) speed
c) thermodynamics
d) completion time
Explanation: Enzymes are responsible for catalyzing reactions by reducing the activation energy. However there is no effect on the thermodynamic aspect of the given reaction.
4. What will happen if heat is applied to an enzyme mediated reaction?
a) Rate will increase
b) pH will increase
c) pH will decrease
d) Denaturation of enzyme
Explanation: The rate of an enzymatic reaction will increase with temperature but only upto a certain limit. Too much heat energy causes the enzyme to denature. This rate varies among different enzymes.
5. Chymotrypsin is a ___________
a) starch
b) polymer
c) buffer
d) enzyme
Explanation: Chymotrypsin is an enzyme that digests food proteins within the small intestine. The active site of this enzyme contains partial positive and partial negative charges.
6. Induced fit in an enzyme refers to ____________________
a) error
b) loop
c) conformational change
d) torsional change
Explanation: Induced fit of an enzyme refers to the conformational change that arises when a substrate molecule comes and binds to an enzyme. As these conformational changes arise, mechanical work is performed the enzyme exerts physical force on certain bonds within the substrate. This has an effect of destabilizing the enzyme, causing it to adopt a transition state in which this strain is relieved.
7. Allosteric site is same as enzyme’s active site.
a) true
b) false
Explanation: Allosteric site is spatially different from enzyme’s active site. It is the site where a compound can bind and lead to inhibition or activation of an enzyme.
8. Feedback inhibition is cell’s mechanism to _____________ the process of anabolism.
a) activate
b) inhibit
c) increase
d) decrease
Explanation: Feedback inhibition acts as a check point. If the formation of products is too much, the product itself acts as the inhibitor of the enzyme thus causing the reaction to stop. Feedback inhibition loop is found in most of the cell’s anabolic and catabolic processes.
9. What is the process of synthesis of glucose by the liver is referred to as?
a) gluconeogenesis
b) neogenesis
c) glycolysis
d) saccharification
Explanation: The anabolic pathway that leads to the formation of glucose is referred to as gluconeogenesis. A cell can synthesize glucose at the same it is utilizing glucose as the source of chemical energy.
10. Why are enzymes required?
a) Enzymes help to yield more product
b) Enzymes increase the activation energy of the reaction
c) Enzymes decrease the activation energy of the reaction
d) Enzymes maintain the equilibrium in the reaction
Explanation: Chemical reactions need certain covalent bond breakage within the reactants. For this, the reactants must contain sufficient kinetic energy called the activation energy. Enzymes act as catalysts that speed up the reaction by lowering the activation energy required for breaking the covalent bonds.