MCQ on Introduction to Biochemistry

Introduction to Biochemistry

1. DNA, RNA and proteins are
a. Homopolymers
b. Linear polymers
c. Monomeres
d. Heteromeres

[expand title=”View Answer and explanation” ] Answer: b. Linear polymers,

Explanation:- DNA, RNA, and proteins are linear polymers composed of repeating monomers joined by covalent bonds. DNA and RNA consist of nucleotides linked by phosphodiester bonds, while proteins are made up of amino acids joined by peptide bonds.[/expand]

2. DNA is aptly known as the
a. Information provider
b. Intermediary in the genetic information flow
c. Work-horse of the cell
d. Cellular structural backbone

[expand title=”View Answer and explanation” ] Answer: A ,

Explanation:- DNA is known as the information provider because it contains the genetic code that determines the characteristics of an organism. The sequence of nucleotides in DNA encodes the instructions for the synthesis of RNA and proteins, which play essential roles in the functioning of cells and organisms. [/expand]

3. RNA is aptly known as the
a. Information provider
b. Intermediary in the genetic information flow
c. Work horse of the cell
d. Cellular structural backbone

[expand title=”View Answer and explanation” ] Answer b Intermediary in the genetic information flow,

Explanation:-RNA is known as the intermediary in genetic information flow because it plays a crucial role in translating the genetic code stored in DNA into functional proteins. RNA is synthesized from DNA in a process called transcription and then used as a template for protein synthesis in a process called translation.

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4. Proteins are aptly known as the
a. Information provider
b. Intermediary in the genetic information flow
c. Work horses of the cell
d. Cellular structural backbone

[expand title=”View Answer and explanation” ] Answer C , Explanation: Proteins are known as the workhorses of the cell because they perform a wide range of essential functions. Proteins are involved in catalyzing biochemical reactions, providing structural support, transporting molecules, and communicating signals within and between cells. Their diverse functions are due to their complex three-dimensional structures and the ability to interact with other molecules in a specific manner. [/expand]

5. The strongest bonds are
a. Non-covalent linkages
b. Covalent bonds
c. Van der Waals forces
d. Hydrophobic interactions

[expand title=”View Answer and explanation” ] Answer b , Explanation: Covalent bonds are the strongest type of chemical bonds, formed by the sharing of electrons between atoms. In a covalent bond, the shared electrons are attracted to the nuclei of both atoms, creating a stable and strong bond. Covalent bonds are important in the formation of molecules and macromolecules, such as DNA, RNA, and proteins.[/expand]

6. Most biochemical reactions rely on
a. Non-covalent linkages
b. Covalent bonds
c. Van der Waals forces
d. Hydrophobic interactions

[expand title=”View Answer and explanation” ] Answer A , Explanation: Most biochemical reactions rely on non-covalent linkages, which are weaker than covalent bonds. Non-covalent linkages include hydrogen bonds, van der Waals forces, electrostatic interactions, and hydrophobic interactions. These weak interactions are important in stabilizing macromolecular structures, such as proteins and nucleic acids, and in facilitating molecular recognition and binding. [/expand]

7. Non-covalent bonds do not include
a. Hydrogen bond
b. Van der Waals forces
c. Sharing or exchange of electrons
d. Electrostatic interactions

[expand title=”View Answer and explanation” ]Ans. C ,

Explanation: Non-covalent bonds do not involve the sharing or exchange of electrons between atoms. Instead, they are weaker interactions that arise from the attraction or repulsion between charged or polar molecules, or from the transient dipole moments that arise in nonpolar molecules. Examples of non-covalent bonds include hydrogen bonds, van der Waals forces, electrostatic interactions, and hydrophobic interactions. [/expand]

8. Electrostatic interaction energy is defined by
a. Coulomb’s law
b. Coombs test
c. Contact distance
d. Hydrogen bonds

[expand title=”View Answer and explanation” ] Answer: A Explanation: The electrostatic interaction energy between charged particles is defined by Coulomb’s law, which states that the force between two charged particles is proportional to the product of their charges and inversely proportional to the square of the distance between them. This law governs the behavior of electrostatic interactions in a variety of contexts, including the interactions between ions, molecules, and proteins in biological systems.[/expand]

9. The energy range of hydrogen bonds is
a. 1 kcal mol-1
b. 3 kcal mol-1
c. 13 kcal mol-1
d. 31 kcal mol-1

[expand title=”View Answer and explanation” ] Option , Explanation: [/expand]

10. The energy of a typical carbon-carbon covalent bond has an energy of
a. 58 kcal mol-1
b. 8 kcal mol-1
c. 5 kcal mol-1
d. 85 kcal mol-1