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

Multiple choice bio-chemistry applications of biotechnology pcr cutting, insertion and ligation of dna gene cloning procedure biotechnological regulations asexual modes of reproduction

DNA polymerase required for synthesizing copies of DNA at high temperature is obtained from

  1. Thermus aquaticus

  2. Cephalosporium minimum

  3. Bacillus megaterium

  4. Thermoproteus species
Reveal answer Fill a bubble to check yourself
A Correct answer
Explanation

A. Thermus aquaticus is a thermophilic bacteria which survives at high temperatures. Thus it's DNA polymerase is evolved to synthesize DNA at high temperature. This DNA polymerase is commercially available as "Taq polymerase" and is used in polymerase chain reaction (PCR).

B. Cephalosporium minimum is a plant pathogen and are producers of antibiotic cephalosporin.
C. Bacillus megaterium is a soil bacteria whose DNA polymerase is not thermo resistant. Hence it cannot synthesize DNA at high temperatures.
D. Thermoproteus species are sulphur utilizing hyperthermophiles which grow is acidic hot springs. Such bacteria are difficult to grow in lab conditions. Although its DNA polymerase can synthesize DNA at high temperatures, due to inability to grow in lab conditions, its DNA polymerase cannot be obtained.
Hence the correct answer is 'Thermus aquaticus'

Multiple choice bio-chemistry applications of biotechnology pcr cutting, insertion and ligation of dna gene cloning procedure biotechnological regulations asexual modes of reproduction

Which of the following techniques is used to make numerous copies of a specific segment of DNA quickly and accurately?

  1. Translation

  2. Transcription

  3. Polymerase chain reaction

  4. Ligase chain reaction
Reveal answer Fill a bubble to check yourself
C Correct answer
Explanation

For making numerous copies of a specific segment of DNA three steps are required

1.Denaturing
2.Annealing
3.Extending
Which is called a polymerase reaction.
So, the correct option is 'Polymerase chain reaction'.

Multiple choice bio-chemistry applications of biotechnology pcr cutting, insertion and ligation of dna gene cloning procedure biotechnological regulations asexual modes of reproduction

Read the following statements carefully and select the correct option:
(A) Source of the restriction enzyme Hind III is E.coli
(B) In biolistic method of gene transfer, mircoparticles made up of gold or tungsten are coated with foreign DNA
(C) Micro-injection method for injecting recombinant DNA is used for animal cell
(D) Primers are chemically synthesized oligonucleotides that are complementary to the regions of DNA in PCR.
How many of the above statement are correct?

  1. Four

  2. Three

  3. Two

  4. One
Reveal answer Fill a bubble to check yourself
B Correct answer
Explanation

A)

Restriction enzymes, also called restriction endonuclease, is a protein that cuts DNA after recognizing a specific sequence of DNA. Hind III is a type  II site-specific deoxyribonuclease restriction enzyme isolated from Haemophilus influenzae that cleaves the DNA via hydrolysis.

B)

In the bolistic method of gene transfer, a gene gun is used to transfer exogenous or foreign DNA  in the cell. A droplet of tungsten powder and genetic material is a bullet. Gold is favored at the place of tungsten as it has better uniformity than tungsten and tungsten can be toxic to cells.

C) 
Micro-injection method for injecting recombinant DNA is used to produce transgenic mice. Harvested oocytes of the mouse are injected with the genetic material and then implanted in the oviduct of a pseudopregnant animal.

D)
A primer is a short strand of RNA or DNA that serves as a starting point for DNA synthesis.In vitro lab techniques that use DNA polymerase, DNA. primers are used. They are usually short, chemically synthesized oligonucleotides, with a length of about twenty bases.
Therefore A, B, and D are correct statements. Answer is B.

Multiple choice biology chemical coordination and integration mechanism of hormone action coordination in human beings- chemical control endocrine system in humans

Positive feedback occurs when

  1. A gene activates itself directly via negative feedback loop

  2. A gene activates itself indirectly via negative feedback loop

  3. A gene activates itself directly and indirectly via double negative feedback loop

  4. None of the above
Reveal answer Fill a bubble to check yourself
C Correct answer
Explanation

Positive feedback occurs when a system's output enhances or amplifies the process that created it. In gene regulation, this often involves complex feedback loops where a gene product directly or indirectly promotes its own further expression.

Multiple choice zoology origin of life and organic evolution neo darwinism mechanism of evolution other theories of evolution

Using imprints from a plate with complete medium and carrying bacterial colonies, you can select streptomycin resistant mutants and prove that such mutations do not originate as adaptation. These imprints need to be used 

  1. Only on plates with streptomycin

  2. On plates with minimal medium

  3. Only on plates without streptomycin

  4. On plates with and without streptomycin
Reveal answer Fill a bubble to check yourself
A Correct answer
Explanation

Plates having streptomycin allow to propagate only those bacteria which are resistant to the antibiotic.

So, the correct answer is 'Only on plates with streptomycin'.

Multiple choice botany bacteria bacteria - friend and foe useful and harmful bacteria bacteria; benefits and harmful effects

Plasmid is used as carrier because

  1. It has antibiotic resistance genes.

  2. It has no replication points.

  3. It can go between eukaryotic and prokaryotic cells.

  4. None of the above.
Reveal answer Fill a bubble to check yourself
A Correct answer
Explanation

The plasmid is an extrachromosomal material in bacteria and used as a carrier DNA because it has antibiotic resistance gene which makes it easy to isolate the transformed cell with the desired insert in it.

Multiple choice botany bacteria bacteria - friend and foe useful and harmful bacteria bacteria; benefits and harmful effects

Insulin, interferons and somatostatin are synthesised using pBR322 plasmids of

  1. Bacillus subtilis

  2. Escherichia coli

  3. Streptomyces

  4. All of the above
Reveal answer Fill a bubble to check yourself
B Correct answer
Explanation
  • pBR322 is a widely-used E. coli cloning plasmid vector. 
  • It was created in 1977 in the laboratory of Herbert Boyer at the University of California San Francisco. The p stands for " plasmid " and BR for "Bolivar " and " Rodriguez ", researchers who constructed it. 
  • By using  pBR322 plasmid of E.coli Insulin, interferons and somatostatin can be synthesized through the genetic engineering procedure.
  • So, the correct answer is 'Escherichia coli'.
Multiple choice biology micro organisms non cellular organism : virus world of virus bacteria - introduction, shape and structure

The latest view for the origin of virus is that

  1. They arose from nucleic acid and protein found in primitive water.

  2. They arose from bacteria as a result of loss of cell wall.

  3. They arose from some of the bacteria, which had developed a nucleus only.

  4. They are modified plasmids, which are fragments of the nucleic acids of the host.
Reveal answer Fill a bubble to check yourself
D Correct answer
Explanation

Viruses play an important role in horizontal gene transfer and genetic diversity. The evolution history showcases the origin of viruses as to have evolved from plasmids when pieces of DNA moved between cells. As
big bits of cellular DNA became independent and some DNA stuck with cell genomes. Thus, the correct answer is option D.

Multiple choice biology option b: biotechnology and bioinformatics pcr cutting, insertion and ligation of dna gene cloning procedure

A set of genes of cDNA is immobilized on a glass slide and used in transcriptome studies is called 

  1. Proteome

  2. Microarray

  3. DNA chip

  4. Genome
Reveal answer Fill a bubble to check yourself
B Correct answer
Explanation

The transcriptome is the sum of all of its RNA transcripts. The information content of an organism is recorded in the DNA of its genome and expressed through transcription. A microarray is a laboratory tool used to detect the expression of thousands of genes at the same time. DNA microarray is microscopic glass slides that are printed with thousands of tiny spots in defined positions with each spot containing a known cDNA. The cDNA is made immobilized on a glass slide.

So, the correct answer is 'Microarray'.

Multiple choice bio-chemistry unit of living - cell eukaryotic cell kinds of cell introduction to eukaryotic cell

The control of gene expression is more complex in eukaryotic cells because the ___________________.

  1. Gene expression differentiaties specialized cells

  2. The chromosomes are linear and more numerous

  3. Operons are controlled by more than one promoter region

  4. inhibitory or activating molecules may not help to regulate transcription
Reveal answer Fill a bubble to check yourself
A Correct answer
Explanation

Eukaryotic gene expression is more complex because it must generate and maintain differentiated cell types (neurons vs. muscle vs. skin), each with specialized gene expression profiles. Option A correctly states this. The other options describe structural features, not regulatory complexity.

Multiple choice botany option b: biotechnology and bioinformatics biotechnology in agriculture gm crops transgenic organisms

Which statement is wrong?

  1. Nucleic acid is fragmented by nucleases

  2. Construction of recombinant DNA involves cleaving DNA segments with endonuclease and rejoining with ligase.

  3. Genetic engineering is making artificial limbs and diagnostic instruments
  4. $T _1$ plasmid transforms cells of plants.
Reveal answer Fill a bubble to check yourself
D Correct answer
Explanation

In plant genetic engineering, the Ti plasmid can be used to carry foreign genes into plant cells. The Ti plasmid is the disease-causing agent of the soil-borne bacteria Agrobacterium tumefaciens. The Ti plasmid was then used to transform petunia cells in culture. So, the correct option is "D" (T1 plasmid transforms cells of plants).

Multiple choice botany option b: biotechnology and bioinformatics biotechnology in agriculture gm crops transgenic organisms

Plasmids are suitable vectors for gene cloning because they are

  1. Small circular DNA molecules with their own origin of replication site

  2. Small circular DNA molecules which can integrate with host chromosomal DNA

  3. Having antibiotic genes

  4. Able to shuttle between prokaryotic and eukaryotic cells
Reveal answer Fill a bubble to check yourself
A Correct answer
Explanation

Plasmids are ideal vectors because they are small, circular, and contain an origin of replication, which ensures they can be maintained and copied by the host cell.