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

Consider the following sugars:

  1. Cellulose 2. Deoxyribose
  2. Fructose 4. Galactose Which of these are monosacchaides?

  1. 1 only

  2. 2 and 3

  3. 2, 3 and 4

  4. 1, 2, 3 and 4
Reveal answer Fill a bubble to check yourself
C Correct answer
Explanation

Monosaccharides are simple sugars that cannot be hydrolyzed into simpler sugars. Deoxyribose (2), Fructose (3), and Galactose (4) are all monosaccharides. Cellulose (1) is a polysaccharide made of glucose units. Option C correctly identifies 2, 3, and 4 as monosaccharides.

Multiple choice

Match List I with List II and select the correct answer using the codes given below the Lists: List I List II (a) One gene and one enzyme theory 1. Watson and Crick (b) Coupling and Repulsion hypothesis 2. Beadle and Tatum (c) Tramsduction in bacteria 3. Bateson and Punnet (d) Semi-conservative method of DNA replication 4. Lederberg and Zinder 5. Morgan Codes:

  1. (a) 2 (b) 3 (c) 4 (d) 1

  2. (a) 2 (b) 1 (c) 4 (d) 5

  3. (a) 4 (b) 2 (c) 3 (d) 5

  4. (a) 5 (b) 3 (c) 2 (d) 1
Reveal answer Fill a bubble to check yourself
A Correct answer
Explanation

One gene-one enzyme theory was proposed by Beadle and Tatum. Coupling and Repulsion phenomenon in genetics was explained by Bateson and Punnett. Transduction in bacteria was discovered by Lederberg and Zinder. The semi-conservative method of DNA replication was demonstrated by Watson and Crick (with Meselson and Stahl's experimental verification). Option A correctly matches these.

Multiple choice

Lysozyme is an enzyme used to break down bacterial cell walls to improve protein or nucleic acid extraction efficiency.The ammonium salt having positive effect on the refolding of denaturated lysozyme is

  1. calcium ammonium nitrate

  2. ceric ammonium nitrate

  3. diammonium phosphate

  4. ethylammonium nitrate
Reveal answer Fill a bubble to check yourself
D Correct answer
Explanation

Ethylammonium nitrate or ethylamine nitrate(EAN) is a salt with formula C2H8N2O3 or(C2H5)NH3+·NO3−. It is an odourless and colourless to slightly yellowish liquid. It is used as an electrically conductive solvent in electrochemistry and as a protein crystallization agent. It has a positive effect on the refolding of denaturated lysozyme, with the refolding yield of about 90%.

Multiple choice

Pol refers to a gene in retroviruses. The pol gene does NOT encode for

  1. RNA polymerase

  2. integrase

  3. reverse transcriptase

  4. proteases

  5. trimer
Reveal answer Fill a bubble to check yourself
A Correct answer
Explanation

This enzyme is involved in the production of RNA from DNA through transcription. It adds ribonucleotides to growing RNA transcripts at the 3’ end. The pol gene does not encode for NA polymerase.

Multiple choice

Which among the following statements does NOT characterise telomerase reverse transcriptase enzyme?

  1. The hTERT gene has become a main focus for gene therapy involving cancer.

  2. Plasmid DNA sequences can be manufactured using the hTERT promoter.

  3. hTERT immortalises various normal cells in culture.

  4. The hTERT gene, located on chromosome 5, consists of 16 exons and 15 introns spanning 35 kb.

  5. Telomere deficiency is associated with cancers and tumor formation.
Reveal answer Fill a bubble to check yourself
E Correct answer
Explanation

Telomere deficiency is often linked to aging, cancers and the conditions dyskeratosis congenita (DKC) and Cri du chat. Meanwhile, over-expression of hTERT is often associated with cancers and tumor formation.

Multiple choice

The protein coded by a tumor suppressor gene in humans is

  1. a protein which controls progression through the cell cycle

  2. a protein which helps prevent apoptosis

  3. a protein which codes for a DNA repair enzyme

  4. a protein which forms fractions of a growth factor signalling pathway

  5. a protein which acts by opposing the action of PI3K
Reveal answer Fill a bubble to check yourself
A Correct answer
Explanation

Tumour suppressor genes code for proteins which normally control progression through a cell cycle checkpoint. These genes only contribute to a cancer when both copies are mutated in a way which produces an inactive protein product. A single mutation inactivating one gene only has no effect. They contribute to cancer because the absence of the protein product removes controls on cell division.

Multiple choice

What is merozygote?

  1. Recombinant formed in transformation

  2. Combination of bacterial and temperate phage genome

  3. Temporary RNA-DNA diploid formed during reverse transcription

  4. Two bacteria joined by conjugation tube
Reveal answer Fill a bubble to check yourself
A Correct answer
Explanation

The recombinant formed in transformation with slightly more amount of DNA is known as mrerozygote or partial zygote.

Multiple choice

What is F-factor?

  1. Single-stranded RNA

  2. Double-stranded circular genomic DNA

  3. Single-stranded circular genomic DNA

  4. Double-stranded circular plasmid DNA
Reveal answer Fill a bubble to check yourself
D Correct answer
Explanation

F-factor is a double-stranded plasmid DNA.

Multiple choice

An operon is a

  1. functioning unit of chromosome containing a cluster of DNA molecules under the control of a single promoter

  2. functioning unit of genomic DNA containing a cluster of genes under the control of a single promoter

  3. functioning unit of genomic DNA containing a cluster of genes under the control of a single operator

  4. functioning unit of chromosome containing a cluster of DNA molecules under the control of a single operator
Reveal answer Fill a bubble to check yourself
B Correct answer
Explanation

An operon is a functioning unit of genomic DNA containing a cluster of genes under the control of a single promoter.

Multiple choice

A region of DNA that controls hereditary characters is known as ___.

  1. chromosome

  2. chromatin

  3. gene

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

A gene is a specific region of DNA that contains the instructions for a particular hereditary characteristic. While chromosomes contain many genes and chromatin is the DNA-protein complex, the gene is the functional unit that controls specific traits.

Multiple choice

Which of the following sentences about plasmids is untrue?

  1. Plasmid is always a double-stranded DNA molecule.

  2. Plasmid is always circular.

  3. Plasmid is coated with histone protein.

  4. Plasmid does not carry any vital gene necessary for the cell.
Reveal answer Fill a bubble to check yourself
C Correct answer
Explanation

Plasmid is naked without histone protein.