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

Which of the following statements is incorrect regarding the bacteriophages?

  1. Bacteriophage genomes are especially mosaic.

  2. Bacteriophages may have a lytic cycle or a lysogenic cycle.

  3. Bacteriophages are composed of glycolipids.

  4. Bacteriophages are seen as a possible therapy against multi-drug-resistant strains of many bacteria.

  5. Phages are widely distributed in locations populated by bacterial hosts.
Reveal answer Fill a bubble to check yourself
C Correct answer
Explanation

Bacteriophages are composed of proteins that encapsulate a DNA or RNA genome and may have relatively simple or elaborate structures. Their genomes may encode as few as four genes and as many as hundreds of genes.

Multiple choice

A division of the circular single-stranded viruses has been proposed for easy and convenient study. Which of the following types of genomes is characterised by a small circular DNA genome?

  1. Type I genomes

  2. Type II genomes

  3. Type III genomes

  4. Type IV genomes

  5. Type V genomes
Reveal answer Fill a bubble to check yourself
A Correct answer
Explanation

Type I genomes are characterized by a small circular DNA genome (approximately 2-kb), with the Rep protein and the major open reading frame (ORF) in opposite orientations. This type is characteristic of the circoviruses, geminiviruses and nanoviruses.

Multiple choice

Which of the following enzymes is responsible for inducing cleavage of a single double-stranded DNA molecule between the antigen receptor coding segment and a flanking recombination signal sequence?

  1. DNA-dependent protein kinase (DNA-Pk)

  2. Artemis nuclease

  3. Terminal deoxynucleotidyl transferase (TdT)

  4. Recombination activating gene (RAG)
Reveal answer Fill a bubble to check yourself
D Correct answer
Explanation

RAG enzymes work as a multi-subunit complex to induce cleavage of a single double-stranded DNA (dsDNA) molecule between the antigen receptor coding segment and a flanking recombination signal sequence.

Multiple choice

Which of the following statements is/are false about DNA binding proteins?

  1. In humans, replication protein A is used in processes where the double helix is separated, including DNA replication, recombination and DNA repair.
  2. DNA-binding proteins have specific affinity for only double stranded DNA.
  3. Sequence-specific DNA-binding proteins generally interact with the major groove of B-DNA.

  1. Only 1

  2. Only 2

  3. Only 3

  4. Only 1 and 2

  5. Only 2 and 3
Reveal answer Fill a bubble to check yourself
B Correct answer
Explanation

This option is correct. DNA-binding proteins have a specific affinity for either single stranded or double stranded DNA.

Multiple choice

Polymerase chain reaction (PCR) based markers were developed to ______.

  1. differentiate between different biotypes of gall midge

  2. manufacture antibiotics

  3. create termination codon

  4. obtain soil micro-organisms with the help of reductase enzyme
Reveal answer Fill a bubble to check yourself
A Correct answer
Explanation

PCR-based markers are used in molecular biology to identify genetic variations. They are specifically useful for distinguishing between different biotypes of organisms like the gall midge.

Multiple choice

Which was the first DNA-based genome to be sequenced?

  1. MS2 phage

  2. phi X 174 phage

  3. Lambda phage

  4. T4 phage

  5. P1 phage
Reveal answer Fill a bubble to check yourself
B Correct answer
Explanation

The phi X 174 bacteriophage was the first DNA-based genome to be sequenced. This work was completed by Fred Sanger and his team in 1977.

Multiple choice

Which of the following statements is FALSE regarding enzymes?

  1. The term enzyme was proposed by Kuhne.

  2. The first enzyme molecule to be isolated in pure crystalline form was urease.

  3. Synthesis of enzymes is regulated by inducer and repressor genes.

  4. DNA ligase is first isolated from bacteriophages.

  5. Ribozyme is RNA with enzyme activity.
Reveal answer Fill a bubble to check yourself
C Correct answer
Explanation

Synthesis of enzymes is regulated by operator and regulator genes.

Multiple choice

Which of the following is not matched correctly?

  1. Restriction enzymes - DNA cutting enzymes

  2. Restriction fragments - Pieces of DNA that have been cut into different lengths

  3. DNA fingerprinting - Technique for identification of patterns that occur in DNA

  4. Recombinant DNA technology - Combining genes from different species

  5. Genomic library - All the genes contained in one kind of organism
Reveal answer Fill a bubble to check yourself
E Correct answer
Explanation

A genomic library is a collection of cloned DNA pieces from a genome.

Multiple choice

Which of the following statements is not correct about deoxyribonucleic acid?

  1. Plasmids are circular pieces of double stranded DNA that exist separately from chromosomal DNA.

  2. Plasmids that can be propagated in cells of two or more different species are called expression vectors.

  3. Shuttle vectors can be used in both eukaryotes and prokaryotes.

  4. A cloning vector is a small piece of DNA into which a foreign DNA fragment can be inserted for cloning purposes.

  5. Replacement vector is a cloning vector in which part of the normal genome is replaced by foreign DNA.
Reveal answer Fill a bubble to check yourself
B Correct answer
Explanation

Plasmids that can be propagated in cells of two or more different species are called shuttle vectors. An expression vector is generally a plasmid that is used to introduce a specific gene into a target cell.

Multiple choice

Restriction enzymes are known as

  1. Molecular blades

  2. Molecular scissors

  3. Molecular cutters

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

Correct.Restriction enzymes make cut at specific position in DNA segment.

Multiple choice

The function of exonuclease is

  1. to remove nucleotides from the ends of DNA

  2. to add nucleotides to the ends of DNA

  3. to remove nucleotides at specific position

  4. to add nucleotides at specific position
Reveal answer Fill a bubble to check yourself
A Correct answer
Explanation

Correct ans: Exonuclease enzyme cleaves nucleotides one at a time from the ends of DNA.