Biology
DNA and Genetics
1,095 Questions
DNA and genetics questions explore molecular biology, DNA replication, and genetic engineering techniques. These topics are essential for various competitive exams requiring a strong foundation in life sciences. Practice these questions to understand complex biological processes thoroughly.
DNA replication mechanismsGenetic engineering techniquesGene editing toolsPolymerase chain reactionDNA sequencing methods
DNA and Genetics Questions
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retroviruses
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adenoviruses
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ssDNA viruses
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cellular life forms
C
Correct answer
Explanation
The 5′ end of the nicked strand is transferred to a tyrosine residue on the nuclease and the free 3′ OH group is used by the DNA polymerase to synthesise the new strand.
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DNA polymerase
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DNA gyrase
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Primase
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DNA ligase
B
Correct answer
Explanation
DNA gyrase moves ahead of DNA helicase, removing the torques which come in the way.
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Adding DNA primer to enable replication of DNA
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Adding RNA primer to enable replication of DNA
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Priming DNA for replication by preventing formation of nicks
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Unwinding double helix to prime it for DNA replication
B
Correct answer
Explanation
Primase adds RNA primer to enable replication of DNA.
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RNA polymerase
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DNA polymerase
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primase
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DNA gyrase
B
Correct answer
Explanation
It polymerises DNA from a template of RNA.
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DNA gyrase
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DNA helicase
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DNA polymerase
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reverse transcriptase
B
Correct answer
Explanation
Primasome is a complex of primase with DNA helicase.
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DNA gyrase
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DNA ligase
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Primase
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Topoisomerase
D
Correct answer
Explanation
During DNA replication, topoisomerase regulates the overwinding or underwinding of DNA.
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chromosomes
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oxysomes
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mesosomes
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episomes
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spherosomes
D
Correct answer
Explanation
Episome is a genetic determinant (as the DNA of some bacteriophages) that can replicate autonomously in bacterial cytoplasm or as an integral part of the chromosomes.
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Vector
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DNA probe
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Plasmid
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Recombinant DNA
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Mutation
B
Correct answer
Explanation
DNA probes are small segments of DNA, which help detect the presence of a gene of a long DNA sequence in a biological system.
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These are extra chromosomal materials found in bacterial cell.
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Mostly they cannot be transmitted from cell to cell by transformation.
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They can be integrated into the host chromosome.
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They are integral but inert part of the genetic element.
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The term plasmid was first introduced by the American molecular biologist Joshua Lederberg in 1952.
B
Correct answer
Explanation
Plasmid host-to-host transfer requires direct mechanical transfer by conjugation, or changes in incipient host gene expression allowing the intentional uptake of the genetic element by transformation.
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splicing
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cloning
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typing
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finger printing
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hybridization
B
Correct answer
Explanation
DNA cloning is the process of creating multiple copies of isolated DNA fragments.
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enzymes
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restriction endonuclease
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restriction exonucleases
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DNAse
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DNA methylase
B
Correct answer
Explanation
Restriction endonucleases are enzymes that cleave DNA at specific nucleotide sequences.
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Gyrase
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Transcriptase
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Hexokinse
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Taq polymerase
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Reverse transcriptase
D
Correct answer
Explanation
It is a thermostable DNA polymerase named after the thermophilic bacterium Thermus aquaticus. It is the enzyme most widely used in the Polymerase Chain Reaction (PCR).
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LINE
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SINE
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Segmental duplications
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DNA transposons
A
Correct answer
Explanation
LINE (L stands for long) is a small piece of foreign DNA that have been inserted into the chromosomes of a multicelled organism by foreign agents such as retroviruses. LINEs include an open reading frame for reverse transcriptase.
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Gene amplification
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Point mutation
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Translocation
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Deletion
A
Correct answer
Explanation
Yes, it is the correct answer. HER-2/neu activation in breast cancer, the predominant genetic mechanism for oncogene activation is through an amplification of a gene. It is an important prognostic indicator.
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Pattern matching
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Knocking out
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Sequence motif
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Sequence analysis
B
Correct answer
Explanation
In genetics, knocking out a gene implies that particular gene would not be expressed. Altering the genotype of an individual normally alters the phenotype. For example, if you knocked out a particular gene and found out that the resulting fly has underdeveloped wings compared to the wild-type, it could suggest the gene has a role in embryonic wing development.