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

What is true about DNA polymerase used in PCR?

  1. It is used to ligate introduced DNA in recipient cells.

  2. It serves as selectable marker.

  3. It is isolated from a virus.

  4. It is active at high temperature.
Reveal answer Fill a bubble to check yourself
D Correct answer
Explanation

The DNA polymerase used in PCR (like Taq) is derived from thermophilic bacteria, making it heat-stable and capable of remaining active through the repeated high-temperature denaturation cycles.

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

Amplification of gene of interest by using PCR may go upto

  1. 0.1 million

  2. 1.0 million

  3. 1.0 billion

  4. 1.0 trillion
Reveal answer Fill a bubble to check yourself
C Correct answer
Explanation

PCR is a powerful technique for amplifying DNA sequences. Through repeated cycles of denaturation, annealing, and extension, a single DNA molecule can be amplified to approximately 1 billion copies.

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 is isolated from which bacteria?

  1. E. coli

  2. Bacillus thuringiensis

  3. Thermus aquaticus

  4. Agrobacterium
Reveal answer Fill a bubble to check yourself
C Correct answer
Explanation

Taq polymerase is named after the bacterium Thermus aquaticus, which lives in hot springs and provides a heat-stable enzyme necessary for PCR.

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

Polymerase chain reaction (PCR) is used for

  1. In vivo replication of specific DNA sequence using thermostable DNA polymerase

  2. In vitro synthesis of mRNAIn vivo synthesis of mRNA

  3. In vitro replication of specific DNA sequence using thermostable DNA polymerase

  4. Separation of DNA fragments according to their size
Reveal answer Fill a bubble to check yourself
C Correct answer
Explanation

PCR is an in vitro technique used to amplify specific DNA sequences. It utilizes a thermostable DNA polymerase to synthesize multiple copies of the target DNA.

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

To carry out a polymerase chain reaction (PCR), one must have the catalytic DNA polymerase and

  1. a blueprint or gene map of the sequence one wish to copy

  2. a number of primers from either side of the target DNA in order to get the polymerase replication process- going

  3. a DNA synthesizer machine

  4. a DNA probe
Reveal answer Fill a bubble to check yourself
B 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. Components of PCR include DNA template, DNA polymerase, two DNA primers, nucleotides.

So, the correct option is 'a number of primers from either side of the target DNA in order to get the polymerase replication process-ongoing'.

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.