MCQ Bank

Viral genomes can occur in different structural forms depending on the virus. Viral nucleic acid may be linear or circular and can consist of either DNA or RNA.

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Q35

TAF42 and TAF62 from Drosophila have been shown to form a structure similar to that of the ___________tetramer of histones

A) H1.H3
B) H3.H2
C) H1.H4
D) H3.H4

AI Explanation

TAF42 and TAF62 from Drosophila form a structure resembling the histone H3-H4 tetramer. This structural similarity reflects the shared architectural features involved in DNA-associated protein complexes.

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Q35

Cisplatin was found to block cell division in __

A) E. coli
B)
C)
D)

AI Explanation

Cisplatin was found to interfere with DNA and inhibit cell division in bacterial cells such as E. coli. It forms DNA cross-links that disrupt DNA replication and cellular proliferation.

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Q36

.......invokes a flexible element within the polymerase that allows a module at the front of the enzyme, containing the active site.

A) Inchworming
B) Scrunching
C) transient excursion
D) Scrunching and Inchworming

AI Explanation

The inchworming model invokes a flexible element within RNA polymerase that allows the front module containing the active site to move relative to the rest of the enzyme. This model explains how RNA polymerase can translocate during transcription.

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Q36

DNA helicase separate____ DNA into__

A) Double stranded, Single strand
B)
C)
D)

AI Explanation

DNA helicase unwinds the DNA double helix by separating the two complementary strands. This produces two single-stranded DNA templates that can be copied during replication.

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Q37

Bacteria have _________ types of RNA polymerase

A) 5
B) 3
C) 2
D) 1

AI Explanation

Bacteria generally possess one main multisubunit RNA polymerase. Different sigma factors associate with this core enzyme to recognize different promoter classes.

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Q37

DNA consist of ____ helical polynucleotide strands which are wound around the same axis to form ____ double helix___

A) Two, right handed
B)
C)
D)

AI Explanation

DNA consists of two polynucleotide strands wound around the same axis. The common B-form of DNA is a right-handed double helix.

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Q38

____________ is known as the minor form of the spliceosome.

A) Special spliceosome
B) GC-AT spliceosome
C) AT-AC spliceosome
D) AC-TG spliceosome

AI Explanation

The AT-AC spliceosome is the minor spliceosome found in eukaryotic cells. It recognizes and removes the rare AT-AC class of introns.

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Q38

DNA helicases can have a polarity of either___

A) 5’3’ or 3’5’
B)
C)
D)

AI Explanation

DNA helicases move along a nucleic acid strand with a defined polarity. Depending on the helicase, movement can occur in either the 5′→3′ or 3′→5′ direction.

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Q39

The 5’ splice site is recognized by:

A) U2AF
B) U4 SnRNP
C) U5 SnRNP
D) U1 SnRNP

AI Explanation

U1 snRNP recognizes the 5′ splice site through base pairing between its snRNA and the pre-mRNA splice-site sequence. This recognition is an early step in spliceosome assembly.

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Q39

How many different types of amino acids are present___

A) 20
B)
C)
D)

AI Explanation

Proteins are constructed from 20 standard amino acids encoded by the genetic code. Different combinations and sequences of these amino acids produce the enormous diversity of proteins.

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Q40

There are ___________ repeats of CTD are present in the yeast Pol II

A) 12
B) 27
C)
D)

AI Explanation

Yeast RNA polymerase II contains 27 tandem repeats of the characteristic CTD heptapeptide sequence. The CTD is important for transcription and coordination of RNA processing.

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Q40

The length of DNA around nucleosome also varies from one organism to the other ranging from about____

A) 170-240bp
B)
C)
D)

AI Explanation

The DNA associated with a nucleosome and its linker region can vary among organisms. The stated range is approximately 170–240 base pairs.

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Q41

Pol I is required for the expression of only one gene, that encoding the_____________precursor

A) tRNA
B) All given
C) mRNA
D) rRNA

AI Explanation

RNA polymerase I is responsible primarily for transcription of the precursor rRNA gene. This precursor is processed to generate the major ribosomal RNA components.

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Q41

Nucleoside is___

A) Nucleotide – phosphoric acid
B)
C)
D)

AI Explanation

A nucleoside consists of a nitrogenous base attached to a sugar. A nucleotide is a nucleoside plus one or more phosphate groups, so removing phosphoric acid from a nucleotide gives a nucleoside.

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Q42

TFIIE, a general transcription factor consists of_______subunits

A) 3
B) 2
C)
D)

AI Explanation

TFIIE is a general transcription factor composed of two subunits. It helps recruit and regulate TFIIH during RNA polymerase II transcription initiation.

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Q42

The group of adjacent nucleotides are joined by____

A) Phosphodiester bond
B)
C)
D)

AI Explanation

Adjacent nucleotides in nucleic acids are connected through phosphodiester bonds. These bonds link the 3′ hydroxyl group of one sugar to the 5′ phosphate group of the next nucleotide.

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Q43

During initial transcription, RNA polymerase produces and releases short RNA transcripts of_____________

A) <10 nucleotides
B) <5 nucleotides
C)
D)

AI Explanation

During initial transcription, RNA polymerase can repeatedly produce and release short, abortive RNA transcripts of fewer than 10 nucleotides. Productive elongation begins after the polymerase escapes the promoter.

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Q43

RNA can base-pair with complementary regions of either___

A) RNA or DNA
B)
C)
D)

AI Explanation

RNA can form complementary base pairs with another RNA molecule or with a DNA strand. This pairing is important in processes such as RNA secondary-structure formation and RNA-DNA hybridization.

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Q44

____________polymerase can initiate a new RNA chain on a DNA template

A) RNA
B) DNA
C)
D)

AI Explanation

RNA polymerase can initiate a new RNA chain directly on a DNA template without requiring a primer. This is a key distinction from DNA polymerase, which generally requires a pre-existing primer.