Engineering Questions with Answers - Multiple Choice Questions

MCQs on Bioenergetics

1 - Question

. Reactions that lose heat are termed as _____________
a) endothermic
b) exothermic
c) chemical
d) physical

View Answer

Answer: b
Explanation: Energy can neither be created nor be destroyed. It is only transduced from one form into another. Heat is also a form of energy; reactions in which heat is lost to the surroundings are termed as exothermic reactions and those in which heat is gained from the system are termed as endothermic reactions.

2 - Question

According to laws of thermodynamics, the energy of the Universe is _________ whereas the entropy ______________
a) constant, increases
b) constant, decreases
c) increases, remains constant
d) decreases, remains constant

View Answer

Answer: a
Explanation: According to the first and second laws of thermodynamics, the energy of the universe remains constant however the entropy increases owing to the randomness.

3 - Question

Exergonic processes are thermodynamically unfavorable.
a) True
b) False

View Answer

Answer: b
Explanation: The processes having negative Gibbs free energy (-ΔG) are termed as exergonic; are thermodynamically favored and are spontaneous in nature. Processes having +ΔG are endergonic, thermodynamically unfavorable and non-spontaneous.

4 - Question

. Hydrolysis of ATP is which type of reaction?
a) Physical
b) Mechanical
c) Endergonic
d) Exergonic

View Answer

Answer: d
Explanation: Hydrolysis of ATP is the most important chemical reaction in a living cell. It is highly favorable and exergonic with a standard free energy (ΔG⁰’) between reactants and products equal to -7.3 kcal/mol.

5 - Question

Cellular metabolism is a non-equilibrium metabolism.
a) True
b) False

View Answer

Answer: a
Explanation: Cellular metabolism is essentially a non-equilibrium metabolism; that is the ratio of reactants to products is maintained in a non-equilibrium state. This makes most of the reactions irreversible.

6 - Question

Which of the following are responsible virtually for every reaction that takes place inside a cell?
a) Carbohydrates
b) ADP
c) Nucleic acids
d) Enzymes

View Answer

Answer: a
Explanation: Enzymes are the catalysts responsible for virtually everything that takes place inside a cell. Without these catalysts the cellular metabolism and bioenergetics would be imperceptible.

7 - Question

Protein catalysts are called __________ and RNA catalysts are called _____________
a) enzymes, ribozymes
b) ribozymes, enzymes
c) enzymes, ribosomes
d) ribosomes, enzymes

View Answer

Answer: a
Explanation: RNA catalysts are called ribozymes whereas protein catalysts are called enzymes. Most of the catalysts are enzymes made of proteins.

8 - Question

The non-protein constituents of conjugated proteins are called ___________
a) enzymes
b) cofactors
c) amino acids
d) nucleosides

View Answer

Answer: b
Explanation: The non-protein constituents of conjugated proteins (that act as enzymes) are called cofactors. These cofactors can be inorganic metals or organic coenzymes.

9 - Question

Enzymes have no effect on which of the following, in a chemical reaction?
a) activation energy
b) speed
c) thermodynamics
d) completion time

View Answer

Answer: c
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.

10 - Question

. 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

View Answer

Answer: a
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.

11 - Question

. Chymotrypsin is a ___________
a) starch
b) polymer
c) buffer
d) enzyme

View Answer

Answer: d
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.

12 - Question

Induced fit in an enzyme refers to ____________________
a) error
b) loop
c) conformational change
d) torsional change

View Answer

Answer: c
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.

13 - Question

Allosteric site is same as enzyme’s active site.
a) True
b) False

View Answer

Answer: b
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.

14 - Question

. Feedback inhibition is cell’s mechanism to _____________ the process of anabolism.
a) activate
b) inhibit
c) increase
d) decrease

View Answer

Answer: b
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.

15 - Question

. What is the process of synthesis of glucose by the liver is referred to as?
a) gluconeogenesis
b) neogenesis
c) glycolysis
d) saccharification

View Answer

Answer: a
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.

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