MCQ Bank

The tertiary structure describes the complete three-dimensional arrangement of a protein's atoms within a single polypeptide chain. It is stabilized by interactions among amino acid side chains and other molecular forces.

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Q45

A gene coding sequence is a series of __________ nucleotide codons.

A) 5
B) 2
C) 4
D) 3

AI Explanation

A gene coding sequence is organized into codons, and each codon contains three nucleotides. Each codon specifies an amino acid or a termination signal during translation.

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Q45

Which of following purine base is present in RNA__

A) Guanine
B)
C)
D)

AI Explanation

Guanine is a purine nitrogenous base found in both DNA and RNA. The other purine base, adenine, is also present in RNA.

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Q46

The branchpoint site in RNA editing, is present on ___________.

A) DNA ligase
B) Exons
C) Introns
D) Both introns and Exons

AI Explanation

The branchpoint site is located within an intron of a pre-mRNA molecule. A conserved adenosine at this site participates in the first transesterification reaction during splicing.

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Q46

Which nucleotides are considered as purine__

A) adenine & Guanine
B)
C)
D)

AI Explanation

Adenine and guanine are the two purine bases found in nucleic acids. They have a characteristic fused double-ring structure.

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Q47

TFIIB protein is a __________polypeptide chain, enters the preinitiation complex

A) single
B) double
C)
D)

AI Explanation

TFIIB is a single polypeptide-chain general transcription factor. It enters the RNA polymerase II preinitiation complex and helps position the polymerase for transcription initiation.

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Q47

Avery performed his experiment to give evidence about DNA is heredity material___

A) 1944
B)
C)
D)

AI Explanation

Oswald Avery and his colleagues published their landmark experiment in 1944. Their work provided strong evidence that DNA, rather than protein, is the hereditary material responsible for bacterial transformation.

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Q48

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

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

AI Explanation

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

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Q48

The helical twist of the α-helix found in all proteins is__

A) right-handed
B)
C)
D)

AI Explanation

The α-helix found in naturally occurring proteins is predominantly right-handed. Its structure is stabilized by hydrogen bonds between backbone carbonyl and amino groups.

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Q49

____________ nucleotide or nucleoside can be accommodated by group I binding pocket.

A) Adenine
B) Thymine
C) Guanine
D) Uracil

AI Explanation

The group I binding pocket can accommodate uracil-containing nucleotides or nucleosides. Uracil is a pyrimidine base characteristic of RNA.

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Q49

The DNA polymerase require a primer with a free___

A) 3’-OH
B)
C)
D)

AI Explanation

DNA polymerase cannot initiate DNA synthesis without a primer. It extends the primer by adding nucleotides to its free 3′-OH group.

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Q50

TFIIH controls the ____________transition of the preinitiation complex to the open complex

A) ATP-dependent
B) AMP-dependent
C)
D)

AI Explanation

TFIIH uses ATP-dependent helicase activity to unwind promoter DNA. This converts the closed preinitiation complex into the open complex needed for transcription initiation.

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Q50

The bond angles in protein primary structure resulting from rotations at C are labelled (psi) for the____ bond ___

A) Alpha C-C
B)
C)
D)

AI Explanation

The psi (ψ) angle represents rotation around the Cα–C bond in the protein backbone. The phi (φ) angle, in contrast, represents rotation around the N–Cα bond.

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Q51

large subunit of ___________has a carboxy-terminal domain (CTD), which is referred to as the “tail”

A) Pol I
B) Pol II
C)
D)

AI Explanation

The large subunit of RNA polymerase II contains a carboxy-terminal domain (CTD), commonly called its tail. The CTD is extensively phosphorylated and coordinates transcription with RNA-processing events.

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Q51

First enzyme diastase discovered by___

A) Anseime Payen in 1833
B)
C)
D)

AI Explanation

The first enzyme, diastase, was discovered by Anselme Payen and Jean-François Persoz in 1833. Diastase was identified for its ability to break down starch.

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Q52

All eukaryotes have __________ types of RNA polymerases

A) 5
B) 7
C) 2
D) 3

AI Explanation

Eukaryotic cells generally contain three major nuclear RNA polymerases: Pol I, Pol II, and Pol III. Each polymerase specializes in transcribing different classes of RNA.

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Q52

About ____ of all amino acid residues in polypeptides are found in α-helices.__

A) one-forth
B)
C)
D)

AI Explanation

Approximately one-fourth of all amino acid residues in polypeptides are found in α-helices. The α-helix is a common secondary structure stabilized by regular backbone hydrogen bonding.

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Q53

Select the incorrect statement regarding spliceosomes:

A) In performing even a single splicing reaction, the spliceosome hydrolyzes several molecules of ATP
B) It is believed that many of the functions of the spliceosome are performed by its RNA components rather than the proteins
C) Spliceosomes complex comprises about 150 proteins and five RNAs
D) Spliceosomes are larger in size compared to a ribosome

AI Explanation

This is the incorrect statement because the spliceosome is a dynamic complex whose protein and RNA composition is more extensive and variable than this simplified description. The other statements correctly describe important features of spliceosome structure and ATP-dependent activity.

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Q53

The palm domain of DNA Polymerase is composed of a ___ sheet and contains the primary elements of the catalytic site.__

A) Beta
B)
C)
D)

AI Explanation

The palm domain of DNA polymerase contains a central beta sheet. This domain forms important parts of the enzyme's catalytic site responsible for nucleotide addition.

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Q54

transition from initiation to elonagation phase involves the ___________enzyme shedding most of its initiation factors

A) Pol II
B) Pol I
C)
D)

AI Explanation

The transition from transcription initiation to elongation involves RNA polymerase II shedding many initiation factors. CTD phosphorylation helps recruit factors required for productive elongation.