Chapter 21 - Biotechnology and Genetic Modification

Describe Genetic Modification

Changing the genetic material of an organism by removing, changing, or inserting individual genes.

Advantages of using Bacteria in Genetic Modification

1. Rapid reproduction rate

2. Ability to make complex molecules

3. Presence of plasmids - Easily transferred from one organism to another.

4. Few ethical concerns - Bacteria does not have pain receptors and does not feel pain. Bacteria are simpler organisms compared to animals.

Production of Ethanol using anaerobic respiration by Yeast

Equation: Glucose → Ethanol + Carbon Dioxide + Energy

Starch in Maize catalyzed by Amylase into Glucose

Glucose from Maize and Sugarcane is used as energy by Yeast to do anaerobic respiration to produce Ethanol and Carbon Dioxide in absence of oxygen and release a small amount of energy.

Bread-Making using Anaerobic Respiration by Yeast

Equation: Glucose → Carbon Dioxide + Ethanol + Energy

Flour is mixed with Water and Yeast.

Amylase breaks down the starch in the Flour to Glucose.

Yeast uses glucose as energy to do anaerobic respiration and produce Carbon dioxide.

The ethanol produced is broken down and yeast is killed in baking.

Gluten makes the dough stretchy and the bubbles of carbon dioxide causes it the dough to rise.

Use of Pectinase in Fruit Juice

Pectinase is an enzyme breaks down Pectin, to increase the yield of Fruit Juice, and to Clarify the Juice since it breaks down insoluble molecules to soluble ones.

Enzymes in Biological Washing Powders

The enzymes break down large molecules into smaller, water-soluble and colorless molecules.

1. Protease: breaks down protein stains to amino acids.

2. Amylase: breaks down starch stains into glucose.

3. Lipase: breaks down greasy stains (fats) into fatty acids and glycerol.

Biological Washing Powders are packed into water-soluble capsules to prevent the Enzymes catalyzing fats and proteins on the skin (living tissues).

Use of Lactase in Lactose-free milk

Lactase in an Enzyme that breaks down Lactose to produce Glucose and Galactose.

So people that doesn’t have Lactase can consume milk without the side effects.

What are Fermenters?

Fermenters are containers used in large-scale production that is used to grow microorganisms (bacteria and fungi) to produce useful products (insulin, mycroprotein, pencillin).

Products produced by Fermenters

1. Insulin: Human Protein made by Genetically modified Bacteria.

2. Pencillin: An Antibiotic made by the fungus Pencillium.

3. Mycoprotein: A Food made by a fungus Fusarium.

Controlled Conditions in Fermenters

1. Temperature: Optimum temp to ensure enzymes can work efficiently.

Temperature is measured and monitored by a probe.

High temp: Cold water is passed around the fermenter through a water jacket.

Low temp: Hot water or steam is passed around the fermenter through a water jacket.

2. pH: Optimum pH to ensure enzymes work efficiently and to prevent denaturation.

pH is measured and monitored by a pH probe.

Carbon dioxide produced lowers the pH. pH is adjusted by adding small amounts of acidic / alkaline liquids.

3. Oxygen: For organisms to do aerobic respiration.

Low levels of Oxygen: Air is bubbled through the fermenter.

High levels of Oxygen: Waste gasses escape through the outlet in the fermenter, to prevent pressure buildup.

4. Nutrient Supply: For growth and respiration.

• Water and nutrients added to fermenter.

• Glucose may be added for energy for respiration.

• Amino acids or Nitrate Ions may be added to provide a source of nitrogen so that organisms are able to make protein.

5. Waste Products: By Sterilization, It prevents contamination in the culture.

Sterilization: Passing steam through the fermenter to kill microorganisms.

Culture: A mixture of microorganisms growing in a nutrient liquid or agar jelly.

Genetic Modification using Bacterial Production of a Human Protein

1. Isolation of the Human DNA making up the gene using Restriction Enzymes, forming sticky ends.

2. Cutting of the Bacterial Plasmid DNA using Restriction Enzymes, forming complementary sticky ends.

3. DNA Ligase joins the piece of Human DNA to the cut Bacterial Plasmid DNA, forming a Recombinant Plasmid.

4. The Recombinant Plasmid formed is then inserted back into the Bacteria Cell.

5. The Genetically modified Bacteria is then grown in a fermenter to increase the population of the bacteria as the human DNA is expressed to produce the protein.