6.7 - Biotechnology

Biotechnology encompasses various techniques used to analyze and manipulate DNA and RNA, enabling advancements in genetics, medicine, and biotechnology.

Key Techniques

1. Gel Electrophoresis:

   • Purpose: Separates DNA fragments by size.

   • Process: DNA samples are loaded into a gel, and an electric current is applied. Smaller fragments move faster and further through the gel, allowing for separation based on size.

2. Polymerase Chain Reaction (PCR):

   • Purpose: Amplifies (copies) specific target sequences of DNA.

   • Process: Involves repeated cycles of heating and cooling to denature DNA, anneal primers, and extend new DNA strands, resulting in the exponential amplification of the target sequence.

3. DNA Sequencing:

   • Purpose: Determines the precise sequence of nucleotides in a piece of DNA.

   • Application: Used in research, medical diagnostics, and forensic science to identify genetic information.

4. Bacterial Transformation:

   • Purpose: Introduces foreign DNA into bacterial cells.

   • Process:

     • Recombinant Plasmid: A plasmid is engineered to contain the gene of interest (e.g., human insulin gene) and often a selectable marker gene (e.g., antibiotic resistance gene).

     • Restriction Enzymes: These enzymes cut the plasmid and the target DNA to create compatible ends that can be ligated together.

     • Transformation: The recombinant plasmid is introduced into bacterial cells, which then express the foreign gene.

Gene Cloning

Purpose: Produces multiple copies of a specific gene.

• Process:

  • Bacteria are transformed with recombinant plasmids containing the gene of interest.

  • The bacteria are grown on culture dishes, where only a small percentage will successfully take up the plasmid.

  • Selective Pressure: An antibiotic resistance gene in the plasmid allows for the selection of transformed bacteria. Antibiotics kill off non-transformed bacteria, leaving only those with the recombinant plasmid.

Natural Processes in Prokaryotes

• Plasmid Uptake: Prokaryotes can naturally take up plasmids from their environment.

• Conjugation: Plasmids can be transferred between bacteria through direct cell-to-cell contact.