Genetic Research and Biotechnology
Molecular Biology
Molecular biology is the study of the structures and functions of nucleic acids and
proteins. It involves investigating genetic disorders and altering the genetic makeup of
organisms to synthesize useful products.
Recombinant DNA Technology
Recombinant DNA refers to DNA that has been prepared by combining fragments from
different sources, often genomes of different species. This technology became possible
with the discovery of restriction enzymes or restriction endonucleases.
Restriction Enzymes
Restriction enzymes recognize specific sequences called target sequences and cut
DNA at specific locations within those sequences called restriction sites. Most restriction
enzymes produce staggered cuts, resulting in sticky ends that can form base pairs with
complementary single-stranded regions. Some restriction enzymes produce blunt ends.
Protecting DNA Fragments - Methylases
Methylases are enzymes that modify the recognition site of a restriction enzyme by
placing a methyl group on one of the bases. This prevents the restriction enzyme from
cutting the DNA into fragments, allowing molecular biologists to protect a specific gene
fragment.
Making a Recombinant DNA Molecule
Recombinant DNA molecules are created by cutting two fragments from different
sources with the same restriction enzyme, producing complementary single-stranded
sticky ends. Base pairing between the sticky ends brings the fragments together, and
DNA ligase joins the strands to produce double-stranded recombinant DNA.
Gene Cloning in Bacteria
Gene cloning is the process of producing several identical copies of a gene. In this
process, a recombinant molecule is created with the gene of interest and a circular
piece of bacterial DNA called a plasmid. The recombinant DNA is taken up by bacterial
Molecular Biology
Molecular biology is the study of the structures and functions of nucleic acids and
proteins. It involves investigating genetic disorders and altering the genetic makeup of
organisms to synthesize useful products.
Recombinant DNA Technology
Recombinant DNA refers to DNA that has been prepared by combining fragments from
different sources, often genomes of different species. This technology became possible
with the discovery of restriction enzymes or restriction endonucleases.
Restriction Enzymes
Restriction enzymes recognize specific sequences called target sequences and cut
DNA at specific locations within those sequences called restriction sites. Most restriction
enzymes produce staggered cuts, resulting in sticky ends that can form base pairs with
complementary single-stranded regions. Some restriction enzymes produce blunt ends.
Protecting DNA Fragments - Methylases
Methylases are enzymes that modify the recognition site of a restriction enzyme by
placing a methyl group on one of the bases. This prevents the restriction enzyme from
cutting the DNA into fragments, allowing molecular biologists to protect a specific gene
fragment.
Making a Recombinant DNA Molecule
Recombinant DNA molecules are created by cutting two fragments from different
sources with the same restriction enzyme, producing complementary single-stranded
sticky ends. Base pairing between the sticky ends brings the fragments together, and
DNA ligase joins the strands to produce double-stranded recombinant DNA.
Gene Cloning in Bacteria
Gene cloning is the process of producing several identical copies of a gene. In this
process, a recombinant molecule is created with the gene of interest and a circular
piece of bacterial DNA called a plasmid. The recombinant DNA is taken up by bacterial
