Biotechnology Principles and Processes Test - 4

Plasmids are extra nuclear DNA that can multiply itself. RER is protein and plastids (green) helps in photosynthesis. Mitochondria play important role in respiration.

Insertional inactivation is the inactivation of a gene upon insertion of another gene inside in its place or within its coding sequence. It help in identification of recombinant clones.

The genes encoding resistance to antibiotics such as ampicillin, chloramphenicol,tetracycline or kanamycin, etc., are considered useful selectable markers for E. coli. The normal E. coli cells do not carry resistancea gainst any of these antibiotics.

Kanamycin does not inhibit the growth of Escherichia coli bacteria. This antibiotic is used to treat infection caused by Gram-negative bacteria.

There are three basic steps in genetically modifying an organism: 

• Identification of DNA with desirable genes;
• Introduction of the identified DNA into the host;
• Maintenance of introduced DNA in the host and transfer of the DNA to its progeny

When recombinant DNA is transferred into Escherichia coli, a bacterium closely related to Salmonella, it could replicate using the new host’s DNA polymerase enzyme and make multiple copies. The ability to multiply copies of antibiotic resistance gene in E. coli was called cloning of antibiotic resistance gene in E. coli. .

Having two antibiotic resistance genes in the same plasmid helps in identifying transformants. Transformants take up the plasmid and also integrate it into recombinant DNA.

Insertional inactivation is a technique used in recombinant DNA technology and involves inactivation of a gene by inserting a fragment of DNA into the middle of its coding sequence. Any future products from the inactivated gene will not work because of the extra codes added to it. It help in identification of recombinant clone.

The cell of fungi is made of chitin. Chitinase enzyme can hydrolyses this and DNA can be isolated from fungi.

The polymerase chain reaction is a technology in molecular biology used to amplify a single copy or a few copies of a piece of DNA. Calcium ions is not required in PCR technology.

Bacteria contain extra nuclear DNA in plasmids. Resistance to antibiotics in bacteria is due to this plasmid. Most infection causing bacteria can become resistance to at least some antibiotics.

The joining of DNA involves several processes. After having cut the source DNA as well as the vector DNA with a specific restriction enzyme,the cut out ‘gene of interest’ from the source DNA and the cut vector with space are mixed and ligase is added. This results in the preparation of recombinant DNA. Vector is incorporated into recipient cell for cloning to obtain desired product.