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 biochemical techniques manipulation of dna electrophoresis isolation and separation of dna

Having become an expert on gel electrophoresis, you are asked to examine a gel for a colleague. Where would you find the smallest segments of DNA?

  1. Near the positive electrode, farthest away from the wells

  2. Near the negative electrode, close to the wells

  3. Near the negative electrode, farthest away from the wells

  4. Near the middle, they tend to slow down after the first few minutes
Reveal answer Fill a bubble to check yourself
A Correct answer
Explanation

Since DNA is itself negatively charged, it would move towards the positive electrode. In gel electrophoresis, DNA fragments are separated on the basis of charge and masses. Thus, smaller the DNA fragment farther it moves from the well.

So, the correct option is A.

Multiple choice bio-chemistry biochemical techniques manipulation of dna electrophoresis isolation and separation of dna

Gel electrophoresis is used for

  1. Construction of recombinant DNA by joining with cloning vectors

  2. Isolation of DNA molecules

  3. Cutting of DNA into fragments

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

Gel electrophoresis is used to separate macromolecules like DNA, RNA and proteins. DNA fragments are separated according to their size. 

So, the correct option is 'Option D' .

Multiple choice bio-chemistry biochemical techniques manipulation of dna electrophoresis isolation and separation of dna

Select the correct option to fill up the blanks.


(i) _____ is a natural polymer extracted from ______.

(ii) The DNA fragments purified by gel electrophoresis are used in constructing _____ by joining them with ______.
(iii) The ligation of alien DNA is carried out at a _____ present in one of the two ____ in a plasmid vector.
(iv) _____ enzyme remains active during the high temperature-induced denaturation of ds DNA. DNA fragments are resolved according to their ______
(v) through _____ in agarose gel electrophoresis.

  1. (i) Agarose, seaweeds (ii) recombinant DNA, cloning vector (iii) restriction site, antibiotic resistance genes (iv) Taq polymerase, size(v) sieving effect.

  2. (i) Agarose, sea weeds (ii) Restriction site, antibiotic resistance genes (iii) recombinant DNA, cloning vector (iv) Taq polymerase (v) size, sieving effect

  3. (i) Agarose, sea weeds (ii) restriction site, antibiotic resistance genes (iii A-DNA, cloning vector (iv) Taq polymerase (v) size, sieving effect

  4. (i) Size, sieving effect (ii) agarose, sea weeds (iii) recombinant DNA, cloning vector (iv) Taq polymerase (v) restriction site, antibiotic resistance genes
Reveal answer Fill a bubble to check yourself
A Correct answer
Explanation

Agarose is a natural polymer extracted from sea weeds. The DNA fragments purified by gel electrophoresis are used in constructing recombinant DNA by joining them with the cloning vector. The ligation of alien DNA is carried out at a restriction site present in one of the two antibiotic resistance genes in a plasmid vector. Taq polymerase enzyme remains active during the high temperature-induced denaturation of dsDNA.  DNA fragments are resolved according to their size through a sieving effect in agarose gel electrophoresis.

So, the correct option is 'Option A'.

Multiple choice

Which enzyme plays a crucial role in the DNA amplification process during PCR?

  1. DNA polymerase

  2. RNA polymerase

  3. Reverse transcriptase

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

DNA polymerase is the enzyme responsible for synthesizing new DNA strands during PCR, extending the primer sequences and amplifying the target DNA region.

Multiple choice

What is the role of primers in PCR?

  1. To initiate DNA synthesis

  2. To terminate DNA synthesis

  3. To bind to the DNA template

  4. To amplify the DNA region of interest
Reveal answer Fill a bubble to check yourself
A Correct answer
Explanation

Primers are short DNA sequences complementary to the ends of the target DNA region. They bind to the template DNA and provide a starting point for DNA polymerase to initiate DNA synthesis.

Multiple choice

What is the purpose of a thermal cycler in PCR?

  1. To maintain precise temperatures during the PCR cycles

  2. To separate DNA fragments based on size

  3. To detect amplified DNA products

  4. To purify DNA samples
Reveal answer Fill a bubble to check yourself
A Correct answer
Explanation

A thermal cycler is a device used in PCR to precisely control the temperature changes required for the different steps of the PCR cycle (denaturation, annealing, and extension).

Multiple choice

What is the role of DNA polymerase in DNA replication?

  1. It unwinds the DNA double helix.

  2. It synthesizes new DNA strands.

  3. It proofreads the newly synthesized DNA strands.

  4. It separates the two DNA strands.
Reveal answer Fill a bubble to check yourself
B Correct answer
Explanation

DNA polymerase is the enzyme responsible for synthesizing new DNA strands during replication, adding nucleotides to the growing DNA chain in a template-directed manner.

Multiple choice

Which enzyme is used to cut DNA at specific sequences?

  1. Restriction endonuclease

  2. DNA ligase

  3. RNA polymerase

  4. Reverse transcriptase
Reveal answer Fill a bubble to check yourself
A Correct answer
Explanation

Restriction endonucleases are enzymes that cut DNA at specific sequences.

Multiple choice

Which biotechnology technique is used to separate DNA fragments based on their size?

  1. Gel Electrophoresis

  2. DNA Microarray

  3. Polymerase Chain Reaction (PCR)

  4. DNA Sequencing
Reveal answer Fill a bubble to check yourself
A Correct answer
Explanation

Gel electrophoresis is a technique used to separate DNA fragments based on their size by applying an electric current to a gel containing the DNA samples.

Multiple choice

Which bioinformatics approach is commonly used for analyzing protein sequences?

  1. Protein sequencing

  2. Microarray analysis

  3. Molecular docking

  4. Phylogenetic tree construction
Reveal answer Fill a bubble to check yourself
A Correct answer
Explanation

Protein sequencing is a technique used to determine the amino acid sequence of a protein, enabling the study of protein structure, function, and interactions, as well as the identification of post-translational modifications.

Multiple choice

The binding of a protein to DNA can regulate gene expression by:

  1. Blocking the access of RNA polymerase to the promoter region

  2. Activating the transcription of a gene

  3. Repressing the transcription of a gene

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

The binding of a protein to DNA can regulate gene expression by blocking the access of RNA polymerase to the promoter region, activating the transcription of a gene, or repressing the transcription of a gene. The specific effect depends on the type of protein and the location of its binding site on the DNA.

Multiple choice

Which of the following techniques is commonly used to study biomolecular interactions?

  1. X-ray crystallography

  2. Nuclear magnetic resonance (NMR) spectroscopy

  3. Surface plasmon resonance (SPR)

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

X-ray crystallography, nuclear magnetic resonance (NMR) spectroscopy, and surface plasmon resonance (SPR) are all powerful techniques that are commonly used to study biomolecular interactions. These techniques provide detailed information about the structure and dynamics of biomolecular complexes, helping us understand the molecular mechanisms underlying various biological processes.

Multiple choice

What is the name of the enzyme that catalyzes the replication of DNA?

  1. DNA polymerase

  2. RNA polymerase

  3. Reverse transcriptase

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

DNA polymerase is the enzyme that catalyzes the replication of DNA.

Multiple choice

What is the name of the enzyme that unwinds the DNA double helix during replication?

  1. Helicase

  2. Polymerase

  3. Ligase

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

Helicase is the enzyme that unwinds the DNA double helix during replication.