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

Identify the correct sequence of steps in the construction of recombinant DNA.
$(1)$ use restriction enzymes
$(2)$ use DNA ligase
$(3)$ remove plasmid from parent bacterium
$(4)$ introduce plasmid into new host bacterium.

  1. $1-2-3-4$
  2. $4-3-2-1$
  3. $3-1-2-4$
  4. $2-3-1-4$
Reveal answer Fill a bubble to check yourself
D Correct answer
Explanation
Generation  of rDNA steps:
1) The DNA for insulin is first disengaged. 
2) A plasmid made of DNA is expelled from a bacterial cell. 
3) A limitation protein cuts the plasmid DNA open, leaving sticky finishes. 
4) The insulin quality, with integral sticky closures, is included. 
5) DNA ligase catalyst grafts (joins) together with the plasmid DNA and the Insulin DNA. 
6) The plasmid (now hereditarily changed) is embedded again into the bacterium. 
7) The bacterium has cell, partitions and delivers duplicates of the plasmid. 
8) The Bacterium makes human insulin utilizing the quality in the plasmid. 
9) The insulin is removed from the bacterial culture.
So, the correct option '2−3−1−4'.
Multiple choice botany option b: biotechnology and bioinformatics insertion and ligation of dna cutting, insertion and ligation of dna biotechnology in agriculture

Which one of the following is called polynucleotide joining enzyme?

  1. Polymerase I

  2. Polymerase II

  3. Ligase

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

Ligase is nick named as 'molecular sutures'. In Biochemistry, ligase is defined as an enzyme that can catalyze the joining of two large molecules by forming a new chemical bond.

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

Read the following four statements (A-D) about certain mistakes in two of them:

(A) The first transgenic buffalo, Rosie produced milk which was human alpha-lactalbumin enriched.
(B) Restriction enzymes are used in isolation of DNA from other macro-molecules.
(C) Downstream processing is one of the steps of r-DNA technology.
(D) Disarmed pathogen vectors are also used in transfer of r-DNA into the host.

Which are the two statements having mistakes?

  1. Statements (A) and (B)

  2. Statements (B) and (C)

  3. Statements (C) and (D)

  4. Statements (A) and (C)
Reveal answer Fill a bubble to check yourself
A Correct answer
Explanation

(A) Rosie was the first transgenic cow and its milk was rich in human alpha-lactalbumin protein.

(B) Restriction enzymes are used in the isolation of the specific segment of DNA from the DNA of the organism because these enzymes are capable of cutting the DNA at the specific location.
(C) Downstream processing is one of the steps in the r-DNA technology. It involves the extraction and purification of the desired product.
(D) Disarmed pathogens like Agrobacterium tumifaciens, phage viruses are also used in the transfer of r-DNA into the host.
Hence, the correct answer is '(A) and (B)'

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

A dicotyledonous plant forms crown gall when

  1. Agrobacterium tumefaciens comes in contact with the plant

  2. Agrobacterium rhizogenes comes in contact with the plant

  3. A specific part of DNA from the Ti plasmid gets integrated with the plant chromosome

  4. A specific part of DNA from the Ri plasmid gets integrated with the plant chromosome
Reveal answer Fill a bubble to check yourself
C Correct answer
Explanation

Crown gall disease is caused by Agrobacterium tumefaciens, which transfers a specific segment of its Ti plasmid (T-DNA) into the plant genome.

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

Consider the following steps during recombinant DNA technology.
a. Breaking of donor DNA using restriction enzyme
b. Culture of cloned bacteria containing the fragment of donor DNA
c. Isolation of suitable plasmid
d. Insertion of recombinant DNA through cloning
e. Joining of donor DNA with a suitable plasmid using ligase
The correct sequence of these is?

  1. $1, 3, 2, 4, 5$
  2. $3, 2, 1, 5, 4$
  3. $1, 3, 5, 4, 2$
  4. $5, 1, 3, 4, 2$
Reveal answer Fill a bubble to check yourself
A Correct answer
Multiple choice botany option b: biotechnology and bioinformatics insertion and ligation of dna cutting, insertion and ligation of dna biotechnology in agriculture

Which of the following tools of recombinant DNA technology is incorrectly paired with its use?

  1. Reverse transcriptase-production of.cDNA from mRNA

  2. DNA polymerase-used in polymerase chain reaction to amplify section of DNA

  3. DNA ligase-enzyme that cuts DNA, creating the sticky ends of restriction fragments

  4. Restriction enzyme-production of RFLPs
Reveal answer Fill a bubble to check yourself
C Correct answer
Explanation

Restriction enzymes cut DNA creating sticky ends of restriction fragments. While DNA ligase joins these sticky ends to form recombinant DNA. 

So, the correct option is 'DNA ligase-enzyme that cuts DNA, creating the sticky ends of restriction fragments'. 

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

After insertion of DNA segment within the sequence of Z-gene of bacteria, they are grown on chromogenic substrate. After the growth of bacterial colonies, they are identified as
i) Recombinants if colonies are blue- coloured.
ii) Recombinants if colonies are white coloured.
iii) Non-recombinants if colonies are blue- coloured.
iv) Non-recombinants if colonies are white coloured.

  1. iii, iv

  2. i, iv

  3. i, ii

  4. ii, iii
Reveal answer Fill a bubble to check yourself
D Correct answer
Explanation

In insertional inactivation, the Z-gene (encoding beta-galactosidase) is disrupted. If the gene is intact, the bacteria produce the enzyme and turn blue on chromogenic substrate (non-recombinant). If the DNA segment is inserted, the enzyme is not produced, and colonies remain white (recombinant).

Multiple choice zoology applications of biotechnology cloning process of cloning gene cloning

A gene carried by recombinant DNA is cloned when

  1. It's host bacterium divides by binary fission

  2. It is transcribed

  3. It is fragmented by restriction enzymes

  4. It is hybridized
Reveal answer Fill a bubble to check yourself
A Correct answer
Explanation

Vector DNA, with foreign gene is called recombinant DNA. rDNA undergo multiplication by binary fission of host cells or gene cloning process.

So, the correct option is ‘it’s host bacterium divides by binary fisison’.

Multiple choice zoology applications of biotechnology cloning process of cloning gene cloning

With the help of DNA ligase donor DNA fragment is joined. It is called

  1. Molecular cloning

  2. Tissue culture

  3. Protoplasmic fusion

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

Molecular cloning involves using enzymes like DNA ligase to join a donor DNA fragment into a vector (like a plasmid), creating recombinant DNA.

Multiple choice zoology applications of biotechnology cloning process of cloning gene cloning

Which is not a key step in the process of DNA molecular cloning?

  1. Heat shock at $42^oC$ for 90 seconds.

  2. Make DNA competent to take up plasmid with use of calcium chloride

  3. Seal plasmid carrying targeted genes into host cells genome using ligase.

  4. Introduce genes for cloning into a plasmid vector using restriction enzymes.
Reveal answer Fill a bubble to check yourself
A Correct answer
Explanation
A- The steps involved in the process of DNA molecular cloning are – selected DNA fragment is inserted into a plasmid utilizing restriction enzymes and DNA ligase enzymes. The produced molecule of recombinant DNA is then introduced into a selected and grown up bacteria which reproduce by producing an exact copy of the plasmid and transferring it to their progeny.
So, the correct answer is 'Heat shock at 42oC42oC for 90 seconds'
Multiple choice zoology molecular basis of inheritance the search for genetic material dna structure and replication molecular genetics

Gel electyrophoresis is used for

  1. Construction of recombinant DNA by joining with cloning vectors

  2. Isolation of DNA molecule

  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 separates DNA fragments based on their size/molecular weight through an agarose or polyacrylamide gel matrix when an electric current is applied, allowing analysis of fragment lengths.