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 zoology genetics of the future hgp and dna fingerprinting dna fingerprinting human genome project and dna fingerprinting

The technique used to increase the amount of DNA available for analysis is
I. Cloning a plasmid
II. Gel electrophoresis
III. PCR

  1. II only

  2. I and II

  3. I and III

  4. II and III

  5. I, II, and III
Reveal answer Fill a bubble to check yourself
C Correct answer
Explanation
The polymerase chain reaction (PCR) is a technique used in molecular biology to amplify a single copy of DNA to millions of copies of a particular DNA sequence. 
Molecular cloning is a method used to assemble recombinant DNA molecules and to direct their replication within host organisms to increase the number of recombinant DNA molecule. Here, the DNA can be cloned in a plasmid (extracellular DNA).
Thus, the correct answer is option C.


Multiple choice botany classical genetics incomplete dominance deviation from mendelism inheritance

In incomplete dominance, ratio of red: pink: white is

  1. 1:2:1

  2. 1:1:2

  3. 1:2:2

  4. 2:2:1
Reveal answer Fill a bubble to check yourself
A Correct answer
Explanation

Incomplete Dominance is the blending of alleles to create a phenotype that is a combination of both traits the alleles code for. Incomplete dominance is a type of non-Mendelian genetics.

For instance, snapdragon flowers can be either red, white, or pink. If they followed Mendel's inheritance patterns of simple dominance, the flowers would either be red or white in a 3:1 ratio. However, with snapdragon flowers, the ratio of red to pink to white is 1:2:1. This was Mendel's genotype ratio of homozygous dominant to heterozygous to homozygous recessive. This means that the heterozygous plant was actually blending the "dominant" and "recessive" alleles instead of the dominant trait completely masking the recessive trait in the phenotype of the plant. Thus, the correct answer is option A.

Multiple choice zoology molecular basis of inheritance genome projects human genome project human genome project and dna fingerprinting

Human genome project was launched by 

  1. Khorana and others

  2. Bhabha Institute

  3. U.S Department of Energy and National Institute of Health

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

The Human Genome Project was a massive international research effort officially launched in 1990, led primarily by the U.S. Department of Energy and the National Institutes of Health.

Multiple choice zoology molecular basis of inheritance genome projects human genome project human genome project and dna fingerprinting

The state in which the viral genome gets integrated with the bacterial genome is called.

  1. Prophage

  2. Prophase

  3. Adsorption

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

A prophage is the state where a bacteriophage genome is integrated into the host bacterium's DNA. Lysogeny is the cycle itself, but the integrated DNA is specifically called a prophage.

Multiple choice botany caskets of life the cell structure multicellular organisms number and shape of cells

Which one of the following pairs of selectable marker genes and substrates used to select transformed cells is not correctly matched?

  1. Npt II-Kanamycin

  2. Hpt- Hygromycin

  3. Dhfr- Gentamycin

  4. Bar- Bialaphos
Reveal answer Fill a bubble to check yourself
C Correct answer
Explanation

The selectable marker gene dhfr confers resistance to methotrexate, not gentamycin. The other pairs correctly match antibiotic or herbicide resistance genes with their respective selecting agents.

Multiple choice zoology not for breathing not for drinking air pollution and its control air pollution - effects and control environmental issues

Which one of the following is correct?

  1. Catalytic converter can precipitate particular matter of less than $2.5$ $\mu$m.

  2. Histones are acidic and form core of DNA packing.
  3. Template with $5'\rightarrow 3'$ polarity shows continuous DNA replication.

  4. Lactobacillus is not present in dough used for idli preparation.
Reveal answer Fill a bubble to check yourself
D Correct answer
Explanation
Fermentation is required for the preparation of dough and for that, Yeast is used. Lactobacillus is used in the preparation of curd.
A. Catalytic converters primarily work by converting the toxic gases released from the vehicular exhausts into the non-toxic substances before they are released into the atmosphere. 
B. Histones are the basic or positively charged proteins made up of amino acids lysine and arginine. They perform packaging of DNA in eukaryotic cells.
C. DNA template with 5′→3′ polarity shows discontinuous replication via the formation of the Okazaki fragments. The 3′→5′ shows continuous replication.
D. Lactobacillus is the main agent that creates curd from milk. For making the dough, Yeast is used that makes the release of carbon dioxide by fermentation.
Hence, the correct answer is 'Lactobacillus is not present in dough used for idli preparation.'
Multiple choice bio-chemistry nucleic acids central dogma transcription and gene expression molecular biology

The viral enzyme _________ causes the host cell to synthesize a double strand of DNA complementary to the viral RNA.

  1. Zymase

  2. Reverse transcriptase

  3. Enterokinase

  4. None of the above
Reveal answer Fill a bubble to check yourself
B Correct answer
Explanation

Unlike other DNA polymerases, reverse transcriptase (RT) is unique in that it is able to make a complimentary DNA strand from an RNA template. Reverse transciptases are usually found in retroviruses, which use RT to make a DNA copy of their own RNA genome, which is then incorporated into the host cell's genome. 

Zymase is an enzyme complex in yeasts that catalyzes the breakdown of sugar into alcohol and carbon dioxide.
Enterokinase is an enzyme produced by the mucosa of the small intestine. Its sole function is to activate trypsinogen to trypsin.

Therefore, the correct answer is option B.

Multiple choice bio-chemistry nucleic acids central dogma transcription and gene expression molecular biology

Central dogma of molecular biology was modified with the discovery of

  1. Ligase

  2. RNA polymerase

  3. DNA polymerase

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

The central dogma originally stated DNA to RNA to protein. The discovery of reverse transcriptase showed that RNA can serve as a template for DNA synthesis, requiring a modification to the dogma.

Multiple choice dna replication replication and protein synthesis nucleic acids and protein synthesis heredity biology

Which of the following enzyme is used to join DNA fragments?

  1. Terminase

  2. Endonuclease

  3. Ligase

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

DNA ligase is a specific type of enzyme, a ligase, that facilitates the joining of DNA strands together by catalyzing the formation of a phosphodiester bond. It plays a role in repairing single-strand breaks in duplex DNA in living organisms, but some forms may specifically repair double-strand breaks, i.e., a break in both complementary strands of DNA. Single-strand breaks are repaired by DNA ligase using the complementary strand of the double helix as a template, with DNA ligase creating the final phosphodiester bond to fully repair the DNA. DNA ligase has applications in both DNA repair and DNA replication.

Multiple choice dna replication replication and protein synthesis nucleic acids and protein synthesis heredity biology

Deoxyribonucleoside triphosphates serve dual purposes in DNA replication. In addition to acting as substrate, the other function is similar to?

  1. DNA polymerase

  2. rRNA

  3. Topoisomerase

  4. ATP
Reveal answer Fill a bubble to check yourself
D Correct answer
Explanation
Answer :
i) The Deoxyribonucleoside Triposphate act as both energy (ATP) and substrate for the polymerization reaction.
ii) The Deoxyribonucleoside Triposohate (DTPs) is considered as the building block of DNA synthesis.
iii) The DTPs possess two high-energy phosphate that has the ability to provide energy to the replication by breaking their molecules.  
iv) It serves as a substrate that is consumed during the enzymatic reaction of replication.
So correct answer is option D.ATP.

Multiple choice dna replication replication and protein synthesis nucleic acids and protein synthesis heredity biology

DNA replication includes which of the following enzymes?

  1. DNA ligase

  2. DNA polymerase and ligase

  3. RNA polymerase and ligase

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

DNA polymerase and ligase as well as RNA polymerase and ligase have an important role in DNA replication. DNA replication, like all biological polymerization processes, proceeds in three enzymatically catalyzed and coordinated steps : initiation, elongation and termination. All enzymes mentioned play important roles in these steps of replication.

Multiple choice dna replication replication and protein synthesis nucleic acids and protein synthesis heredity biology

Which of the following is true about DNA polymerase?

  1. It can synthesize DNA in the 5' to 3' direction

  2. It can synthesize DNA in the 3' to 5' direction

  3. It can synthesize DNA in both directions

  4. Depend upon the condition
Reveal answer Fill a bubble to check yourself
A Correct answer
Explanation

DNA polymerase enzymes are strictly unidirectional, synthesizing new DNA strands only in the 5' to 3' direction by adding nucleotides to the 3' hydroxyl group.

Multiple choice dna replication replication and protein synthesis nucleic acids and protein synthesis heredity biology

Select the correct statement:

  1. DNA polymerase has high degree of accuracy

  2. During DNA replication, only one strand of DNA act as template for synthesis of new strand.

  3. Taylor has proved by his experiment that DNA is the genetic material
  4. E. coli has $4.6 \times 10^9$ bp in its genetic material
Reveal answer Fill a bubble to check yourself
A Correct answer
Explanation

DNA polymerase has a high degree of accuracy due to its proofreading capability, which allows it to remove incorrectly paired nucleotides during replication.

Multiple choice dna replication replication and protein synthesis nucleic acids and protein synthesis heredity biology

Which of the following enzyme is used in DNA multiplication?

  1. RNA polymerase

  2. DNA endonuclease

  3. Exonuclease

  4. DNA polymerase
Reveal answer Fill a bubble to check yourself
D Correct answer
Explanation

The DNA polymerases are enzymes that create DNA molecules by assembling nucleotides, the building blocks of DNA. These enzymes are essential to DNA replication and usually work in pairs to create two identical DNA strands from a single original DNA molecule. During this process, DNA polymerase reads the existing DNA strands to create two new strands that match the existing ones. Every time a cell divides, DNA polymerase is required to help duplicate the cells DNA, so that a copy of the original DNA molecule can be passed to each of the daughter cells. In this way, genetic information is transmitted from generation to generation.