Biology

DNA and Genetics

985 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

What is the function of the polymerase chain reaction in genetic engineering?

  1. Cut DNA into many fragments

  2. Carry DNA into a new cell

  3. Link together newly joined fragments of DNA

  4. Make millions of copies of a specific segment of DNA
Reveal answer Fill a bubble to check yourself
D Correct answer
Explanation

Polymerase Chain Reaction is a method widely used to make many copies of a specific DNA segment. Using PCR, a single (or more) copy of a DNA sequence is exponentially amplified to generate thousands to millions of more copies of that particular DNA segment.

So, the correct option is 'Make millions of copies of a specific segment of DNA'.

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

In the $PCR$ technology the $DNA$ segment is replicated over a billion times. This repeated replication is catalyzed by the enzyme.

  1. $DNA$ polymerase

  2. Taq polymerase
  3. $DNA$ dependent $RNA$ polymerase

  4. Primase
Reveal answer Fill a bubble to check yourself
B Correct answer
Explanation
Taq polymerase is a thermostable DNA polymerase named after the thermophilic bacterium Thermus aquaticus from which it was originally isolated by Chien et al. in 1976. Its name is often abbreviated to Taq Pol or simply Taq. It is frequently used in the polymerase chain reaction (PCR), a method for greatly amplifying the quantity of short segments of DNA.

T. aquaticus is a bacterium that lives in hot springs and hydrothermal vents, and Taq polymerase was identified as an enzyme able to withstand the protein-denaturing conditions (high temperature) required during PCR. Therefore, it replaced the DNA polymerase from E. coli originally used in PCR. Taq's optimum temperature for activity is 75–80 °C, with a half-life of greater than 2 hours at 92.5 °C, 40 minutes at 95 °C and 9 minutes at 97.5 °C, and can replicate a 1000 base pair strand of DNA in less than 10 seconds at 72 °C.

So the correct option is 'Taq polymerase'.
Multiple choice bio-chemistry applications of biotechnology pcr cutting, insertion and ligation of dna gene cloning procedure biotechnological regulations asexual modes of reproduction

The taq polymerase enzyme is obtained from

  1. Thiobacillus ferroxidans

  2. Bacillus subtilis

  3. Pseudomonas putida

  4. Thermus aquaticus
Reveal answer Fill a bubble to check yourself
D Correct answer
Explanation
Taq polymerase is a thermostable DNA polymerase named after the thermophilic bacterium Thermus aquaticus from which it was originally isolated by Chien et al. in 1976. Its name is often abbreviated to Taq Pol or simply Taq. It is frequently used in the polymerase chain reaction (PCR), a method for greatly amplifying the quantity of short segments of DNA.

T. aquaticus is a bacterium that lives in hot springs and hydrothermal vents, and Taq polymerase was identified as an enzyme able to withstand the protein-denaturing conditions (high temperature) required during PCR. Therefore, it replaced the DNA polymerase from E. coli originally used in PCR. Taq's optimum temperature for activity is 75–80 °C, with a half-life of greater than 2 hours at 92.5 °C, 40 minutes at 95 °C and 9 minutes at 97.5 °C, and can replicate a 1000 base pair strand of DNA in less than 10 seconds at 72 °C.

So the correct option 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 one is a true statement regarding $DNA$ polymerase used in $PCR$

  1. it is used to ligate introduced $DNA$ in recipient cell

  2. it serves as a selectable marker

  3. it is isolated from a virus

  4. it remains active at high temperature
Reveal answer Fill a bubble to check yourself
D Correct answer
Explanation
Taq polymerase is a thermostable DNA polymerase named after the thermophilic bacterium Thermus aquaticus from which it was originally isolated by Chien et al. in 1976. Its name is often abbreviated to Taq Pol or simply Taq. It is frequently used in the polymerase chain reaction (PCR), a method for greatly amplifying the quantity of short segments of DNA.

T. aquaticus is a bacterium that lives in hot springs and hydrothermal vents, and Taq polymerase was identified as an enzyme able to withstand the protein-denaturing conditions (high temperature) required during PCR. Therefore, it replaced the DNA polymerase from E. coli originally used in PCR. Taq's optimum temperature for activity is 75–80 °C, with a half-life of greater than 2 hours at 92.5 °C, 40 minutes at 95 °C and 9 minutes at 97.5 °C, and can replicate a 1000 base pair strand of DNA in less than 10 seconds at 72 °C.

So the correct option is 'it remains active at high temperature'.
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 steps is/are catalysed by Taq polymerase in a PCR?

  1. Denaturation of template DNA

  2. Annealing of primers to template DNA

  3. Extension of primer end on template DNA

  4. All of these
Reveal answer Fill a bubble to check yourself
C Correct answer
Explanation

PCR is the short form for polymerase chain reaction which is the phenomenon which is used for amplification of the part-specific region of DNA as per our interest. Taq polymerase is the enzyme that attaches nucleotides together and help is the extension of primer end on the template DNA.

So, the correct answer is 'extension of primer end on the template DNA'.

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

Taq polymerase enzyme is used in

  1. Restriction mapping

  2. Gene cloning

  3. PCR

  4. All of the above
Reveal answer Fill a bubble to check yourself
C Correct answer
Explanation

Taq polymerase is a heat stable enzyme used in the polymerase chain reaction (PCR) to amplify segments of DNA in the lab. 

Thus, the correct answer is option C.

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 botany heredity: from parents to offsprings experiments of mendel mendel's law of inheritance works of mendel

Two sisters looked exactly the same. This may be due to 

  1. Mitochondrial DNA

  2. Genome

  3. Nucleoli and Nuclei

  4. Protein and RNA
Reveal answer Fill a bubble to check yourself
B Correct answer
Explanation

The identical twins are alike and they are produced from the same zygote. They have the same genome and so, the genes are alike. Due to these, the girls will have the same phenotypic appearance. There will be differences in the random repeats region which do not code for any protein. The mitochondrial DNA will be same as they have been inherited from the same mother. However, the mitochondrial genes are not involved in the phenotype expression. 

Thus, the correct answer is option 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'.