MCQ Bank

Superoxide dismutase (SOD) catalyzes the conversion of superoxide radicals into molecular oxygen and hydrogen peroxide. It is an important antioxidant enzyme that protects cells from oxidative damage.

MB502T Mid Term Verified

Q102

Separation of DNA is accomplished at__

A) chromosome end
B)
C)
D)

AI Explanation

The separation of DNA molecules can be accomplished at chromosome ends during processes involving chromosome segregation and resolution. Chromosome ends are specialized regions called telomeres.

MB502T Mid Term Verified

Q103

Separation of DNA is accomplished by the action of ___

A) Type II topoisomerase
B)
C)
D)

AI Explanation

Type II topoisomerases separate intertwined DNA molecules by making transient double-strand breaks. They pass another DNA segment through the break and then reseal the DNA.

MB502T Mid Term Verified

Q104

Chromosome theory of Inheritance was given by ___ in__:

A) Thomas Hunt Morgan, 1910
B)
C)
D)

AI Explanation

Thomas Hunt Morgan's work with Drosophila provided major experimental support for the chromosome theory of inheritance. His studies linked genes to specific chromosomes and helped establish the chromosomal basis of heredity.

MB502T Mid Term Verified

Q105

The repeating units in nucleic acids are__

A) nucleotides
B)
C)
D)

AI Explanation

Nucleotides are the repeating monomeric units that make up nucleic acids. DNA and RNA are polymers formed by linking nucleotides through phosphodiester bonds.

MB502T Mid Term Verified

Q106

The DNA connecting two nucleosomes is called ___

A) Linker DNA
B)
C)
D)

AI Explanation

The DNA segment connecting two adjacent nucleosomes is called linker DNA. It lies between nucleosome core particles and helps organize DNA into higher-order chromatin structures.

MB502T Mid Term Verified

Q107

Large polypeptide chains usually fold into two or more globular clusters known as___

A) domain
B)
C)
D)

AI Explanation

Large polypeptide chains can fold into two or more compact, independently organized globular regions called domains. Each domain can often have a distinct structural or functional role.

MB502T Mid Term Verified

Q108

Secondary structure of proteins refers to the local confirmation of some part of a ____

A) polypeptide
B)
C)
D)

AI Explanation

Secondary structure describes the local conformation of portions of a polypeptide chain. Common secondary structures include alpha helices and beta sheets, stabilized mainly by hydrogen bonds.

MB502T Mid Term Verified

Q109

If a super coiled DNA molecule receives a ____ the strain of unwinding is immediately removed. ___

A) Nick
B)
C)
D)

AI Explanation

A nick is a break in one strand of a DNA duplex while the complementary strand remains intact. Introducing a nick into supercoiled DNA allows the torsional strain from unwinding to be relaxed.

MB502T Mid Term Verified

Q110

Primary structure or ___ of protein refers to amino___

A) covalent structure
B)
C)
D)

AI Explanation

The primary structure of a protein is its covalent structure, specifically the linear sequence of amino acids joined by peptide bonds. This sequence determines the basis for subsequent protein folding.

MB502T Mid Term Verified

Q111

The first clue that DNA was the carrier of heredity information came from the work of ____ in___:

A) Fred Griffth, 1928
B)
C)
D)

AI Explanation

Frederick Griffith's 1928 transformation experiment provided the first major clue that hereditary information could be transferred between bacterial cells. His work demonstrated that a substance from heat-killed bacteria could transform living bacteria into a different, heritable form.

MB502T Mid Term Verified

Q112

Exposure of DNA to dimethyl nitrosamine leads to___

A) produce mono-adduct
B)
C)
D)

AI Explanation

Dimethyl nitrosamine can react with DNA bases through alkylation. This exposure primarily produces alkylated DNA bases, including mono-adducts, which can cause mutations if not repaired.

MB502T Mid Term Verified

Q113

Which enzyme are called succide enzyme___

A) alkyltransferase
B)
C)
D)

AI Explanation

Alkyltransferases are sometimes called suicide enzymes because they transfer an alkyl group from damaged DNA to themselves. This reaction permanently inactivates the enzyme after a single repair event.

MB502T Mid Term Verified

Q114

Two mammalian 3’ exonuclease, TREX & TREX2 may convert the errors that introduced by ___

A) pol β H
B)
C)
D)

AI Explanation

The mammalian 3′ exonucleases TREX and TREX2 can correct errors introduced during DNA synthesis. They contribute to proofreading by removing incorrectly incorporated nucleotides.

MB502T Mid Term Verified

Q115

Wrong statement about (6-4) photoproduct is

A) They are easily repaired by nucleotide excision repair
B)
C)
D)

AI Explanation

The statement is considered incorrect because (6-4) photoproducts are particularly efficiently repaired by photoreactivation in organisms that possess photolyase. Although nucleotide excision repair can also remove these lesions, describing them as easily repaired specifically by NER is not the expected characterization.

MB502T Mid Term Verified

Q116

Enzyme that converts hydrogen peroxide into water and oxygen is

A) catalase
B)
C)
D)

AI Explanation

Catalase is the enzyme that breaks down hydrogen peroxide into water and molecular oxygen. This reaction protects cells from oxidative damage caused by hydrogen peroxide.

MB502T Mid Term Verified

Q117

During elongation the enzyme RNA Transcriptase adds nucleotide at a time to growing. One tRNA having amino acid join with mRNA during protein synthesis by

A) mRNA
B)
C)
D)

AI Explanation

During protein synthesis, tRNA carrying an amino acid binds to the complementary codon on mRNA through its anticodon. The mRNA therefore serves as the template that directs the correct sequence of amino acids.

MB502T Mid Term Verified

Q118

DNA replication is semi-conservative was proved in

A) 1956, Mathew Meselson & Frankin Stahl
B)
C)
D)

AI Explanation

Meselson and Stahl experimentally demonstrated the semi-conservative nature of DNA replication using nitrogen isotopes in E. coli. Their landmark experiment was published in 1958, although the work was conducted earlier.

MB502T Mid Term Verified

Q119

The size of the bubble length of DNA that is not double helical remains

A) Constant
B)
C)
D)

AI Explanation

During transcription, the locally unwound region of DNA forms a transcription bubble. Its size remains relatively constant as RNA polymerase moves along the DNA template.