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Molecular biology is the study of the molecular mechanisms of biological activity within both cells, which would include molecular synthesis, modification, mechanisms, and interactions. Molecular biology is the study of the physical and chemical framework of biological macromolecules. Biologists use molecular and genetic tools to investigate how molecules function in the complex environment of a living cell. Molecular biology emerged in the 1930s, emerging from the related fields of biochemistry, genetics, and biophysics; it is still closely associated with those fields today. The term "molecular biology" was coined by William Astbury in 1945 to refer to the study of the chemical and physical structure of biological macromolecules.
Sample Questions
1) How does the genetic material manifest itself?
a) By means of replication and transcription
b) By means of transcription and translation
c) By means of translation and modification
d) By means of mutation and transposition
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Answer: b
Explanation: The process by which the sequence of bases in the DNA directs the production of RNAs and proteins that perform cellular functions and define cellular identity is known as an expression of genetic material. Transcription and RNA processing, followed by translation, are the fundamental processes responsible for gene expression.
2)The RNA polymerase's transcription process is very accurate, but not as accurate as replication.
a)True
b) False
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Answer: a
Explanation: Though accurate, transcription is less accurate than replication. In transcription, one error occurs for every 10,000 nucleotides added, compared to 10,000,000 nucleotides for replication. This distinction reflects the absence of a comprehensive proofreading mechanism for transcription, despite the existence of two types of proofreading for RNA synthesis.
3)The α subunits of polymerase has a function of ____________
a) Promoter binding
b) Initiation
c) Elongation
d) Termination
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Solution: a
Explanation: The polymerase subunits are required for core protein assembly but have no clear role in transcription. This subunit, however, is essential for promoter binding.
4) What role does RNA polymerase play in the production of mRNA?
a) RNA polymerase I
b) RNA polymerase II
c) RNA polymerase III
d) RNA polymerase IV
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Solution: a
Explanation: Except for the S rRNA, polymerase I is responsible for the transcription of the various types of rRNA. Polymerase III transcribes S rRNA, with some small nuclear RNA genes and tRNAs. Polymerase II is in charge of mRNA transcription.
5)The E. coli RNA polymerase adds __________ nucleotides per second.
a) 20
b) 30
c) 40
d) 50
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The answer : c.
Explanation: The RNA polymerase from E. coli can synthesize RNA at a rate of 40 nucleotides per second. The RNA polymerase enzyme requires Mg2+ ion and an optimum temperature of 37 C to function properly.
6) What is the function of the ω subunit of RNA polymerase?
a) Subunit association
b) Promoter binding
c) Initiation and elongation
d) Cation binding
Solution: a
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Explanation: The RNA polymerase subunit aids in the association of all the subunits. Subunit promotes promoter binding. The subunit promotes initiation and elongation. The ‘subunit binds to Mg2+ cations.
7)The β subunit of polymerase has a function of ____________
a) Promoter binding
b) Catalytic center
c) Template binding
d) Cation binding
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Answer: b
Explanation: The polymerase subunit is thought to be its catalytic centre. According to research, the subunit may contain two domains that are responsible for transcription initiation and elongation.
8)Four types of σ factors are known of them which one is heat stable?
a) σ70
b) σ32
c) σ54
d) σ28
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Answer: a
Explanation: σ70 is the most common σ factor.
σ32 is highly heat stable.
σ54 is used during N2 deficiency.
σ28 is used for chemotaxis.
9) What is the function of the RNA polymerase subunit?
a) Subunit association
b) Promoter binding
c) Initiation and elongation
d) Cation binding
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Answer: a
Explanation: The RNA polymerase subunit aids in the association of all the subunits. Subunit promotes promoter binding. The subunit promotes initiation and elongation. Subunit binds to Mg2+ cations.
10) Which of the following is not part of the RNA polymerase core enzyme?
a) α
b) β
c) ω
d) σ
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Answer: d
Explanation: The subunit is not a component of the RNA polymerase core enzyme. The structural formula of the RNA polymerase core protein is 2'. With the addition of the subunit, the RNA polymerase core protein is transformed into a holoenzyme.
11) The bacterial system has _____________ RNA polymerases.
a) 1
b) 2
c) 3
d) 4
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The answer: c.
Explanation: There are three RNA polymerases in the bacterial system. There are three of them: RNA polymerase I, RNA polymerase II, and RNA polymerase III. RNA polymerase I is responsible for mRNA synthesis, while RNA polymerases II and III are responsible for specialized RNA synthesis.
12) Which of the following is DNA made up of?
a) Adenine – Guanine
b) Cytosine – Thymine
c) Both Adenine – Guanine & Cytosine – Thymine
d) None of the mentioned
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Answer: c)
Explanation: DNA is a linear molecule composed of four nucleotide bases: adenine (A), cytosine (C), guanine (G), and thymine (T) (T). The arrangement in which these bases appear in the DNA sequence is known as the DNA sequence.
13) Who is regarded as the founder of molecular biology?
a) Linus Carl Pauling
b) James Watson
c) Francis H. Crick
d) Mahlon B. Hoagland
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Answer: a)
Explanation: Francis Crick dubbed Pauling the "Father of Molecular Biology." His identification of sickle cell anaemia as a "molecular illness" paved the way for molecular analysis of genetically acquired changes.
14) Proteins are made up of which of the following?
a) Nucleic acids
b) Amino acids
c) Nuclease
d) None of the mentioned
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Answer: b
Explanation: Proteins are made up of hundreds or thousands of smaller units called amino acids, which are linked together in long chains. A protein is composed of 20 different types of amino acids that can be combined in a variety of ways.
15) Which of the following is wrongly paired?
a) Nucleic acid – hydrogen bond
b) Polysaccharide – glycosidic bond
c) Proteins – peptide bond
d) Phospholipids –phosphate linkage
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Answer: a
Explanation: Nucleic acids, specifically DNA and RNA, exhibit phosphodiesterase linkage, which is the most common type of linkage. The backbone will not form unless phosphodiester bonds are formed between the phosphate and the adjacent 3'OH sugar molecule. As a result, the nucleotides would be unable to attach and bond in order to form a nucleic acid.
16) Which of the following has no contribution to the stability of tRNA?
a) Hydrogen bonding
b) Hydrophobic interactions
c) Base and sugar-phosphate backbone interaction
d) Base pairing
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Answer: b
Explanation: Because of the negative charge of the tRNA backbone, the molecule is unlikely to be hydrophobic. As a result, hydrophobic interactions have no effect on the molecule's structural stability. Other interactions, such as hydrogen bonding, lead to base pairing, which leads to the classic cloverleaf model.
17)Which of the following is not required for DNA sequencing?
a) Polymerase chain reaction
b) Electrophoresis
c) Restriction digestion
d) Cloning
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Answer: d
Explanation: DNA sequencing is the process of determining the exact order of nucleotides within a DNA molecule. It includes restriction endonuclease methods and technologies, electrophoretic techniques, and Polymerase Chain Reaction.
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