22: Cell factories and biotechnologies (idk girls)

Explain why microbes are useful biotechnology, using examples of specific fungi (cerevisae) and bacteria (E.coli)

Microbes are used in biotechnology because they:

• Grow fast and are easy to culture in large quantities.

• Have simple genetics, making it easy to insert or remove genes.

• Can produce useful substances like enzymes, hormones, and antibiotics.

Examples:

• Fungus – Saccharomyces cerevisiae (yeast):
  

  • Used in baking and brewing (ferments sugars → ethanol + CO₂).

  • Used in biotechnology to produce human insulin, hepatitis B vaccine, and other recombinant proteins.

• Bacterium – E. coli:

  • Used as a model organism for genetic engineering.

  • Can carry plasmids with foreign genes (e.g., human insulin gene).

  • Used for mass production of proteins like insulin, growth hormone, enzymes for detergents, etc.

Explain what a plasmid is, and define the roles of different kinds of plasmids in nature and in biotechnology

A plasmid is a small circular DNA molecule found in bacteria, separate from chromosomal DNA.

In nature:

• Plasmids carry extra genes (not essential for survival).

• These genes can provide advantages:

  • Antibiotic resistance (R-plasmids)

  • Toxin production

  • Metabolic abilities (break down unusual substances)

In biotechnology:

• Plasmids are used as vectors ( carriers of foreign DNA)

• Scientists insert desired genes into plasmids, then put them into bacteria (like E. coli).

• The bacteria then replicate, producing copies of the recombinant DNA and expressing the new protein (e.g., insulin, enzymes).

Define the terms “DNA cloning” “recombinant DNA” “GMO”

• DNA cloning:
  The process of making many identical copies of a DNA fragment, gene, or entire organism.

• Recombinant DNA:
  DNA that has been artificially combined from two or more different sources (e.g., human gene + bacterial plasmid).

• GMO (Genetically Modified Organism):
  Any organism whose genetic material has been altered using biotechnology to include a foreign or modified gene.

Explain how recombinant DNA and GMOs are made, and especially which enzymes do which jobs in this process

1. Target gene is cut out using a restriction enzyme (cuts DNA at specific sites).

2. Plasmid is cut open with the same restriction enzyme to make matching sticky ends.

3. DNA ligase joins the gene and plasmid → forms recombinant DNA.

4. The recombinant plasmid is put into a bacterium (e.g., E. coli) = GMO.

5. The bacterium copies the plasmid and produces the protein from the inserted gene.

Main enzymes and their jobs:

• Restriction enzyme: Cuts DNA.

• DNA ligase: Joins DNA pieces.

• DNA polymerase: Copies DNA (e.g., in PCR or when the bacterium replicates).

Discuss why vaccines are important, and how recombinant DNA methods can be used to make

Why vaccines are important:

• They stimulate the immune system to produce antibodies without causing disease.

• They provide immunity and help prevent epidemics.

• They can even help eradicate diseases (e.g., smallpox).

How recombinant DNA is used to make vaccines:

1. The gene coding for an antigen (a surface protein from a pathogen) is identified.

2. The antigen gene is inserted into a plasmid.

3. The plasmid is placed into yeast or bacteria, which then produce large amounts of the antigen protein.

4. The purified antigen is used as a subunit vaccine, safe because no live virus is used.