Unit 20 Biotechnology and genetic modification

What is biotechnology

the use of microorganisms such as bacteria and fungi to make useful products or carry out services for us.

How is bacteria useful in genetic modification and biotechnology (4)

bacteria reproduces very quickly

microbes can covert raw materials into the finished product very quickly unlike plants and animals

Use of bacteria means that food production can be independant of climate

Can produce complex proteins that pass out into the surrounding medium and can be harvested

Examples of enzymes that are produced by bacteria for the food industry: (4)

amylase → breaking down starch→ production of glucose syrup

pectinase → extracting juice from fruit

sucrose → breaking down sucrose → to make confectionary

protease → makes meat more tender

Plasmids and why they are helpful

Plasmids are small circles of DNA, they are easy to work with because they can be replicated easily. Plasmids can be cut open by enzymes and a gene from another organism can be spliced into them

Yeast fermentation word equation

Glucose → alcohol + carbon dioxide + energy released

How is ethanol made as a substitute to petrol?

sugar cane and maize which can be fermented anaerobically to produce ethanol

Why is ethanol a good substitute for petrol?

it has high energy content and is carbon neutral (when burnt does not produce toxic gases, so no increase in co2 content)

What is biodiesel made from?

oil seed rape

Describe the role of yeast in bread making

The yeast ferments the sugar, producing carbon dioxide, gas and alcohol. Bubbles of carbon dioxide get trapped inside the dough that makes it rise. After being baked, the heat causes the alcohol to evaporate

Which enzymes do biological washing powders have? (4)

1. Protease → breakdown of protein stains (blood, grass, egg)
2. Lipases → breaks down fat in grease stains (butter, lipstick, mayonaise)
3. amylase → break down of starch (foods containing starch)
4. cellulases → breakdown of cellulose fibres on the outside of cotton fabrics to remove dirt attached to them

What extracts fruit juices?

Pectinase → breakdown of pectins that act like glue in plant cell walls, used to extract fruit juices and soften vegetables

How is lactose broken down?

Lactose is broken down by lactase, which is the sugar found in milk.

What could happen if lactose is not broken down?

stomach cramps, diarrheoa, wind

What is the word equation for the breakdown of lactose?

lactose→ (broken down by lactase) → glucose + galactose

What are the ideal conditions for fermentation?

correct nutrients, constant pH and temperature

What is invertase?

enzyme extracted from yeast, splits sucrose into glucose and fructose, used to produce soft centres and improve the shelf life of confectionary

What is chymosin? (MSG)

Growing the bacterium Corynebacterium glutamicum in fermenters and isolating glutamate crystals, MSG is used as an ideal seasoning and enhances food flavours

What is rennet?

Rennet was extracted from the stomachs of calves and used to clump milk protein together in cheese and yogurt production

What are the controlled conditions in the Industrial fermenters?

1. Fermentation vessel made of stainless steel and filled with a medium containing the required nutrients (sugars, ammonium salts)
2. Stirrer keeping microorganisms suspended so they have access to nutrients and oxygen, maintaining an even temperature
3. air supply provides oxygen for aerobic respiration of the microbe
4. water cooled jacket to remove the energy released by fermentation and keep temperature constant at 24
5. Probes monitor temperature and make sure the pH is constant at 6.5 adding alkaline if necessary

Define genetic modification

changing the genetic material of an organism by removing, changing or inserting individual genes, allowing the transfer of genes between unrelated species

Human medicines in genetic modification

many human proteins such as insulin, human growth hormones, and blood clotting agents are produced by bacteria that have been genetically modified with human genes, produced and used as medicines

Herbicide resistance in crop plants in genetic modification

The gene makes oilseed rape resistant to the herbicide glufosinate so it the crop is not affected by the herbicide and continues to grow while weeds are destroyed

Insect resistance in crop plants in genetic modification

genetically modified plants produce their own toxins that kills insect larvae that feeds on it, less environmental impact than spraying pesticides because only the insects that are feeding on it get killed

Additional vitamins in crop plants in genetic modification

Golden rice that improves the diets of people that eat it because it contains vitamin A, reduces mortality rates strengthening the immune system

How is insulin produced in an industrial fermenter?

Genetic modification allows for insulin to be made quickly and cheaply on a large scale, the gene that produces insulin is identified, restriction enzymes cut the human insulin making gene from the rest of the DNA, the plasmid is removed from the bacterium and cut open by the restriction enzymes, the insulin making genes are replaced with the plasmids (with sticky ends to join it back), joined by the ligase, the new plasmid is called the recombinant plasmid which is inserted back into the bacterium which now has a gene code for insulin, the bacteria multiplies rapidly inside an industrial fermenter.

Advantages of genetically modified crops (3)

1. solving global hunger: increased food production as the crops that are produced can withstand extreme climate conditions and soil
2. Environmentally friendly: less need for chemical fertilisers that suspend a lot of nitrogen and harm the environment
3. Consumer benefits: better flavour and better keeping properties, easier to produce requiring lesser additives

Disadvantages of genetically modified crops (3)

1. Environmental safety: plants might become weeds if the pollen from crops that are resistant to weedkillers pass on by insects or the wind
2. Food safety: new gene combinations may be produced, could make harmful substances
3. Decreased biodiversity