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 bio-chemistry organization of life concept of metabolism metabolism in animals metabolism

A regulatory gene produces some kind of protein through its mRNA that controls the activity of the operator gene which signals the formation of specific enzymes required for the metabolic breakdown of the food. How does that protein regulate the activity of the operator gene?

  1. The repressor protein produced after combining with an inducer activates the operator gene

  2. The repressor protein produced after combining with a co repressor activates the operator gene

  3. The catabolic activator protein(CAP) produced activates the operator gene

  4. The mutated repressor protein produced activates the operator gene
Reveal answer Fill a bubble to check yourself
A Correct answer
Explanation

In the lac operon model, a repressor protein binds to the operator to block transcription. When an inducer (like lactose) is present, it binds to the repressor, changing its shape so it can no longer bind to the operator, thus activating the gene.

Multiple choice zoology biodiversity and conservation hotspots and methods of conservation biodiversity: conservation conservation of biodiversity basis of classification in animals basis of the classification of animals criteria for animal classification

A collection of cloned DNA fragments that represents the entire genome is called genomic library.

  1. True

  2. False
Reveal answer Fill a bubble to check yourself
A Correct answer
Explanation

A genomic library is a collection of the total genomic DNA from a single organism. The DNA is stored in a population of identical vectors, each containing a different insert of DNA

So, the correct option is 'True'.

Multiple choice zoology biodiversity and conservation hotspots and methods of conservation biodiversity: conservation conservation of biodiversity basis of classification in animals basis of the classification of animals criteria for animal classification

Genomic DNA library is

  1. Packing of donor DNA in a collection of vectors.

  2. A collection of gene vectors.

  3. Collection of organisms for extracting DNA.

  4. A collection of literature about DNA.
Reveal answer Fill a bubble to check yourself
A Correct answer
Explanation

A genomic library is a collection of total genomic DNA from a single organism. This DNA is packed in a population of identical vectors for storage. Each vector contains a different insert of DNA. 


So, the correct option is 'Packing of donor DNA in a collection of vectors.'

Multiple choice zoology biodiversity and conservation hotspots and methods of conservation biodiversity: conservation conservation of biodiversity basis of classification in animals basis of the classification of animals criteria for animal classification

Which is used to select genes from genomic library?

  1. Cloning vectors

  2. DNA probes

  3. Gene targets

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

DNA probes are stretches of single-stranded DNA used to detect the presence of complementary nucleotide sequences (target sequences) by hybridization. Genomic library comprises large number of genes in the form of different nucleotide sequences of DNA fragments and they can be selected with the help of DNA probes.

So, the correct option 'DNA probes'.

Multiple choice bio-chemistry cell membrane regulation of respiration transport of respiratory gases buffer and its role

In a $PCR$, which of the following components is not required?

  1. Nucleotide precursors
  2. A primer containing $3'-OH'$

  3. DNA helicase to separate the strands

  4. DNA polymerase to catalyse the reaction
Reveal answer Fill a bubble to check yourself
A Correct answer
Explanation

A common laboratory technique used to make many copies (millions or billions) of a particular region of DNA is called Polymerase Chain Reaction(PCR). It requires a primer, DNA helicases, DNA polymerases, etc.,

So, the correct option is ‘ Nucleotide precursors’.

Multiple choice biology classification and variation dna - history and structure biotechnology commercial applications of biotechnology

Which one of the following pairs is not correctly matched?

  1. Plasmid - small piece of extrachromosomal DNA in bacteria.

  2. Interferon - an enzyme that helps in DNA replication.

  3. Cosmid - a vector for carrying large DNA fragments into host cells.

  4. Myeloma - tumour cells.
Reveal answer Fill a bubble to check yourself
B Correct answer
Explanation

Interferons (IFNs) are proteins made and released by virally infected host cells in response to the presence of pathogens, such as viruses, bacteria, parasites, or tumor cells to protect the adjacent cells from the infection by interfering the DNA replication of the virus in the host cell. So, the correct answer is option B.

Multiple choice botany option b: biotechnology and bioinformatics insertion and ligation of dna cutting, insertion and ligation of dna biotechnology in agriculture

Precipitates of purified DNA after the addition of chilled ethanol can be seen as a collection of fine threads in suspension. This process is referred as _____________.

  1. DNA transformation

  2. DNA ligation

  3. DNA spooling

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

The purified DNA, after treatment with various enzymes, precipitates out after addition of chilled ethanol. This is viewed as a collection of fine threads in the suspension, and is easily collected. The process is known as DNA spooling.

Multiple choice botany option b: biotechnology and bioinformatics insertion and ligation of dna cutting, insertion and ligation of dna biotechnology in agriculture

Insertional inactivation is related to

  1. Microinjection

  2. Gene gun

  3. Gel electrophoresis

  4. Selection of recombinations
Reveal answer Fill a bubble to check yourself
D Correct answer
Explanation

Insertional inactivation is the inactivation of a gene upon insertion of another gene inside in its place or within its coding sequence. This helps the selection of transformant and as well as recombinant colonies in selective antibiotic medium aided due to insertional inactivation of the antibiotic gene which becomes inactive due to foreign gene insert within its sequence. 

So, the correct option is Selection of recombination.

Multiple choice botany option b: biotechnology and bioinformatics insertion and ligation of dna cutting, insertion and ligation of dna biotechnology in agriculture

A major event in r-DNA technology is _________________.

  1. Separation

  2. Isolation

  3. Elution

  4. Both A and B
Reveal answer Fill a bubble to check yourself
D Correct answer
Explanation

r-DNA technology is the process involving the introduction of a foreign piece DNA containing a gene of interest into the genome of an organism. Isolation and separation is a step in the process in which various techniques are used to separate the required gene (containing the gene of interest) from the nucleus of the cell (free of the other cellular contaminants). The isolated DNA is then restriction digested and amplified to make several copies. It is then inserted into a vector for transfer into an appropriate host. Elution is a step involved in the process of separation of DNA. So, the correct answer is 'isolation and separation'.

Multiple choice botany option b: biotechnology and bioinformatics insertion and ligation of dna cutting, insertion and ligation of dna biotechnology in agriculture

Elution means

  1. Separation of DNA fragments on agarose gel

  2. Cutting and extraction of DNA bands from the agarose gel

  3. Making the DNA bands visible under UV radiation

  4. Isolation of alien DNA from the choice organism
Reveal answer Fill a bubble to check yourself
B Correct answer
Explanation

Elution is the process of extracting DNA fragments from an agarose gel after they have been separated.

Multiple choice

Who discovered that DNA is a double helix?

  1. Archibald Garrold

  2. Watson and Crick

  3. Frederick Griffith

  4. Avery and MacLeod
Reveal answer Fill a bubble to check yourself
B Correct answer
Explanation

James Watson and Francis Crick, using data from Rosalind Franklin and Maurice Wilkins, determined the double helix structure of DNA in 1953.

Multiple choice trihybrid cross classical genetics botany

Trihybrid ratio is

  1. 27 : 9 : 9 : 9 : 3 : 3 : 3 : 1

  2. 27 : 9 : 9 : 6 : 6 : 3 : 3 : 1

  3. 1 : 6 : 15 : 20 : 15 : 6 : 1

  4. 36 : 6 : 6 : 6 : 3 : 3 : 3 : 1.
Reveal answer Fill a bubble to check yourself
A Correct answer
Explanation

A cross is made between the two parents on the basis of 3 contrasting characters is called Trihybrid cross. Mendel conducted trihybrid cross by three characters height of the stem, form of seed, and colour of the cotyledons. In the F2 generation, he obtained, 27:9:9:9:3:3:3:1.

So, the correct option is ‘27:9:9:9:3:3:3:1’.