Tag: dna transfer

Questions Related to dna transfer

Which of the following is required for microinjection method of gene transfer?

botany genetic technology dna transfer rdna technology - dna transfer and transformation gene cloning procedure

  1. Microparticles

  2. Micropipettes

  3. Divalent cations

  4. UV radiations

Show answer
Correct Option: B
Explanation:
Micro-injection method is the direct or vectorless method of gene transfer, in which foreign DNA is directly injected into the nucleus of animal cell or plant cell by using micro-needles or micro-pipettes. It is used to transfer DNA in oocytes, eggs and embryo.
So, the correct answer is 'Micropipettes'.

The term "competent" refers to

botany genetic technology dna transfer rdna technology - dna transfer and transformation gene cloning procedure

  1. Increasing the competition between cells

  2. Making cells impermeable for DNA

  3. Increasing the efficiency with which DNA enters the bacterium through pores in its cell wall

  4. Making cells permeable for divalent cations

Show answer
Correct Option: C
Explanation:
Transformation is a process by which a cell takes up naked DNA fragment from the environment, incorporates it into its own chromosomal DNA and finally expresses the trait controlled by the incoming DNA. Since DNA is a hydrophilic molecule, it can not pass through membranes, so the bacterial cells must be made competent to take up DNA. This is done by treating them with a specific concentration of a divalent cation, such as calcium ($Ca^{2+}) which increases the efficiency with which DNA enters the bacterium through pores in its cell wall.
So, the correct answer is 'Increasing the efficiency with which DNA enters the bacterium through pores in its cell wall'.

Micro-injection is a method used to

botany genetic technology dna transfer rdna technology - dna transfer and transformation gene cloning procedure biotechnology in agriculture

  1. Produce sticky ends of DNA

  2. Provide protection against pathogen

  3. Purify the DNA

  4. Inject recombinant DNA into the nucleus of an animal cell

Show answer
Correct Option: D
Explanation:

Micro-injection is a method used to Inject a recombinant DNA into the nucleus of an animal cell. This is the only way to introduce alien DNA into host cells. 

So, the correct option is 'Option D' .

If a person obtains transformants by inserting a recombinant DNA within the coding sequence of enzyme -galactosidase, he will separate out recombinants from non-recombinants by which of the following observations?

botany biotechnology: principles and processes dna transfer rdna technology - dna transfer and transformation gene cloning procedure biotechnology in agriculture

  1. Non-recombinant colonies do not produce any colour whereas recombinants give blue coloured colonies

  2. Recombinant colonies do not produce any colour whereas non-recombinants give blue coloured colonies

  3. Recombinants and non-recombinants both produce blue coloured colonies

  4. No colonies are formed due to insertional inactivation

Show answer
Correct Option: B
Explanation:

Alternative selectable markers have been developed which differentiate recombinants from the non-recombinants on the basis of their ability to produce colour in the presence of a chromogenic substrate. In this, a recombinant DNA is inserted within the coding sequence of an enzyme, ( -galactosidase. This results into inactivation of the enzyme, which is referred i to as insertional inactivation. The presence of a chromogenic j substrate gives blue coloured colonies if the plasmid in the bacteria does not have an insert. Presence of insert results into insertional inactivation of the -galactosidase and the colonies do not produce any colour, these are identified as recombinant colonies.

In the process of insertional inactivation ________________.

botany biotechnology: principles and processes dna transfer rdna technology - dna transfer and transformation gene cloning procedure biotechnology in agriculture

  1. A recombinant DNA is inserted within the coding sequence of enzyme -galactosidase, resulting in inactivation of the enzyme

  2. A recombinant DNA is inserted within the coding sequence of proteins involved in the replication of the plasmid

  3. A recombinant DNA is inserted within the recognition site for EcoRI

  4. None of the above

Show answer
Correct Option: A
Explanation:

Alternative selectable markers have been developed which differentiate recombinants from the non-recombinants on the basis of their ability to produce colour in the presence of a chromogenic substrate. In this, a recombinant DNA is inserted within the coding sequence of an enzyme, ( -galactosidase. This results into inactivation of the enzyme, which is referred i to as insertional inactivation. The presence of a chromogenic j substrate gives blue coloured colonies if the plasmid in the bacteria does not have an insert. Presence of insert results into insertional inactivation of the -galactosidase and the colonies do not produce any colour, these are identified as recombinant colonies.

If a recombinant DNA bearing gene for resistance to antibiotic ampicillin is transferred to E.coli cells, the host cells become transformed into ampicillin-resistant cells. If such bacteria are transferred on agar plates containing ampicillin, only transformants will grow and the untransformed recipient cells will die. The product produced by transformant bacteria that digests the ampicillin antibiotic is called as - 

botany genetic technology dna transfer rdna technology - dna transfer and transformation gene cloning procedure

  1. Selectable marker

  2. Recombinant protein

  3. Cloning site

  4. Chemical scalpels

Show answer
Correct Option: B

The correct sequence of making a cell competent is

botany genetic technology dna transfer rdna technology - dna transfer and transformation gene cloning procedure

  1. Treatment with divalent cations incubation of cells with recombinant DNA on ice heat shock ($42^0$C) placing on ice

  2. Heat shock ($42^0$C) incubation of cells with recombinant DNA on ice treatment with divalent cations placing on ice

  3. Treatment with divalent cations placing on ice incubation of cells with recombinant DNA on ice heat shock ($42^0$C)

  4. Incubation of cells with recombinant DNA on ice heat shock ($42^0$C) treatment with divalent cations placing on ice

Show answer
Correct Option: A
Explanation:

In order to force a bacteria to take up the plasmid , the bacterial cells must to be made competent. This is done by treating them with a specific concentration of divalent cations such as calcium which increases the efficiency with which the DNA molecule enters into the bacteria through pores in its cell wall. Recombinant DNA then forced into such cells by incubating the cells with recombinant DNA on ice followed by placing them immediately at heat shock and then again into ice. This enables the bacteria to take up the recombinant DNA. 

So, the correct option is 'Option A' .

Statement 1 : In insertional inactivation, blue colour produced by bacterial colonies indicates that the plasmid does not have an insert into the bacterial genome. 
Statement 2: Presence of insert results into insertional inactivation of -galactosidase enzyme and the colonies do not produce any colour.

botany biotechnology: principles and processes dna transfer rdna technology - dna transfer and transformation gene cloning procedure biotechnology in agriculture

  1. Both statements 1 and 2 are correct

  2. Statement 1 is correct but statement 2 is incorrect

  3. Statement 1 is incorrect but statement 2 is correct

  4. Both statements 1 and 2 are incorrect

Show answer
Correct Option: A
Explanation:

Selectable markers have been developed which differentiate recombinants from non- recombinants on the basis of their ability to produce colour in the presence of a chromogenic substrate. In this, a recombinant DNA is inserted within the coding sequence of an enzyme B-galactosidase. This results into an  insertional inactivation. The presence of chromogenic substrate gives blue coloured colonies if the plasmid in bacteria does not have an insert. Presence of insert results into insertional inactivation of a^-galactosidase enzyme and the colonies do not produce any colour, these are identified as recombinant colonies. 

So, the correct option is 'Option A' .

rDNA is

botany genetic technology dna transfer rdna technology - dna transfer and transformation gene cloning procedure

  1. Genomic RNA of virus

  2. Genomic RNA that produces DNA through reverse transcription

  3. DNA found in ribosome

  4. DNA segment speciaiised to form rRNA

Show answer
Correct Option: D
Explanation:

Ribosomal DNA (rDNA) is a DNA sequence that codes for ribosomal RNA. Ribosomes are assemblies of proteins and rRNA molecules that translate mRNA molecules to produce proteins. In the nucleus, the rDNA region of the chromosome is visualized as a nucleolus which forms expanded chromosomal loops with rDNA.

So, the correct answer is 'DNA segment speciaiised to form rRNA.'

Direct visual selection method for the selection of recombinant host cells on the basis of their inability to produce colour in the presence of chromogenic substrate can be applied if the vector used is a

botany biotechnology: principles and processes dna transfer rdna technology - dna transfer and transformation gene cloning procedure biotechnology in agriculture

  1. Modified plasmid vector of E.coli

  2. Modified bacteriophage

  3. Modified Agrobacterium tumifaciens plasmid

  4. Disarmed retroviruse

Show answer
Correct Option: A