Cell Biology Questions and Answers – Bioenergetics

«
»

This set of Cell Biology Multiple Choice Questions & Answers (MCQs) focuses on “Bioenergetics”.

1. 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.
advertisement

2. 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. 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. 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. 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.
advertisement

6. 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. 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. 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. 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.
advertisement

10. 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: d
Explanation: In ordinary reactions, heat is applied to increase the rate of reaction. However in enzyme catalyzed reactions, if heat is applied the enzyme denatures.

11. 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. 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. 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.
advertisement

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

Answer: b
Explanation: Anabolism refers to the synthesis of complex products. Feedback inhibition is a mechanism of cell to shut down its process of anabolism so that unnecessary products are not formed.

15. The process of synthesis of glucose 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.

Sanfoundry Global Education & Learning Series – Cell Biology.

To practice all areas of Cell Biology for Interviews, here is complete set of 1000+ Multiple Choice Questions and Answers.

Participate in the Sanfoundry Certification contest to get free Certificate of Merit. Join our social networks below and stay updated with latest contests, videos, internships and jobs!

advertisement
advertisement
advertisement
Manish Bhojasia, a technology veteran with 20+ years @ Cisco & Wipro, is Founder and CTO at Sanfoundry. He is Linux Kernel Developer & SAN Architect and is passionate about competency developments in these areas. He lives in Bangalore and delivers focused training sessions to IT professionals in Linux Kernel, Linux Debugging, Linux Device Drivers, Linux Networking, Linux Storage, Advanced C Programming, SAN Storage Technologies, SCSI Internals & Storage Protocols such as iSCSI & Fiber Channel. Stay connected with him @ LinkedIn