Biotechnology and Genetic Modification Quiz

Biotechnology, Genetic Modification, and Recombinant DNA Technology

• Biotechnology uses living organisms to create new products. Both traditional (like fermentation) and modern (genetic engineering) methods are included.
• Genetic modification (genetic engineering) alters an organism's DNA to produce desired traits. This may involve adding, deleting, or modifying genes.
• Recombinant DNA technology combines DNA from different sources. Foreign genes are inserted into an organism to produce new proteins or modify traits.

Clones and Vectors in Recombinant DNA

• A clone is a genetically identical copy of an organism, cell, or DNA molecule. In rDNA, a clone contains foreign DNA in its genome.
• A vector is a DNA molecule transporting foreign DNA into a host cell. Common vectors include plasmids and viral vectors. Vectors ensure proper foreign DNA transfer and expression.

Restriction Enzymes in Recombinant DNA

• Restriction enzymes cut DNA at specific nucleotide sequences (restriction sites), acting as molecular scissors. Cuts can create sticky or blunt ends.
• In rDNA, restriction enzymes cut both vector and foreign DNA. Ligase joins the cut DNA fragments to form recombinant DNA.

Vector Properties

• Origin of Replication (ORI): Enables independent vector replication within a host cell.
• Selectable Marker: Identifies cells successfully taking up the vector (e.g., antibiotic resistance).
• Cloning Site (Multiple Cloning Site, MCS): Has several restriction enzyme recognition sites for foreign DNA insertion.
• Reporter Gene: Easily identifies cells with recombinant DNA. Examples include GFP or LacZ.

Plasmid and Viral Vectors

• Plasmid vectors are small, circular DNA in bacteria, easily manipulated and transferred into bacterial cells for cloning and amplification.
• Viral vectors are genetically modified viruses carrying foreign DNA into host cells. Used in gene therapy, they ensure foreign DNA integration, particularly when dealing with larger pieces or mammalian cells.

Polymerase Chain Reaction (PCR)

• PCR amplifies specific DNA sequences.
• Steps:
  • Denaturation (high temp): Separates double-stranded DNA.
  • Annealing (lower temp): Primers bind to single-stranded DNA.
  • Extension (higher temp): Taq polymerase synthesizes new DNA strands.
• PCR is used in DNA fingerprinting, disease diagnosis, and forensic science.

Gene Transfer Methods

• Transformation: Bacterial cells are made competent to absorb foreign DNA. Methods include chemical treatment (e.g., calcium chloride) or electrical pulses (electroporation).
• Electroporation: Uses electric fields to create temporary pores in cell membranes for DNA entry. Suitable for both bacterial and eukaryotic cells.
• Microinjection: Physically injects DNA into a cell using a fine needle. Used in gene therapy and genetic modification experiments.
• Gene Gun (Biolistics): Shoots DNA-coated particles into cells using high-pressure gas. Used for introducing DNA into plant cells.
• Viral Vectors: Modified viruses deliver DNA into host cells. Used for gene therapy or other applications in mammalian cells.