MCQ Bank

CPD photolyase is found in many organisms, including bacteria, plants, fungi, and some animals. Placental mammals, including humans, generally lack functional CPD photolyase and instead rely mainly on nucleotide excision repair.

MB502T Mid Term Verified

Q30

Hydrolytic deamination of cytosine is estimated to take place about _ times a day in a mammalian cell.....

A) 100 to 500
B)
C)
D)

AI Explanation

Spontaneous hydrolytic deamination of cytosine occurs frequently in mammalian cells. It is estimated to occur approximately 100 to 500 times per cell per day, producing uracil from cytosine.

MB502T Mid Term Verified

Q31

Okazaki fragments vary in length from _ nucleotides in bacteria.

A) 1000 to 2000
B)
C)
D)

AI Explanation

Okazaki fragments are short DNA segments synthesized discontinuously on the lagging strand. In bacteria such as E. coli, they typically range from about 1000 to 2000 nucleotides.

MB502T Mid Term Verified

Q32

Griffith theorized that some substance of the dead bacteria might be responsible for that transformation . He called that substance as the transforming principle. _

A) TRUE
B)
C)
D)

AI Explanation

Griffith observed that nonvirulent bacteria could be transformed into virulent bacteria by material from heat-killed virulent cells. He called the unknown material responsible for this change the transforming principle.

MB502T Mid Term Verified

Q33

The RNA AU/GC ratio was roughly _ to the DNA AT/GC ratio___

A) similar
B)
C)
D)

AI Explanation

The AU/GC ratio in RNA was found to be roughly similar to the AT/GC ratio in DNA. This observation provided an early clue about the relationship between RNA and DNA composition.

MB502T Mid Term Verified

Q34

The viral nucleic acid can be__

A) linear or circular
B)
C)
D)

AI Explanation

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.

MB502T Mid Term Verified

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.

MB502T Mid Term Verified

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.

MB502T Mid Term Verified

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.

MB502T Mid Term Verified

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.

MB502T Mid Term Verified

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.

MB502T Mid Term Verified

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.

MB502T Mid Term Verified

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.

MB502T Mid Term Verified

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.

MB502T Mid Term Verified

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.

MB502T Mid Term Verified

Q44

The overall three dimensional arrangement of all atoms in a protein is referred as____

A) Tertiary structure of protein
B)
C)
D)

AI Explanation

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.

MB502T Mid Term Verified

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.

MB502T Mid Term Verified

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.

MB502T Mid Term Verified

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.

MB502T Mid Term Verified

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.