21) Biotechnology and genetic modification Flashcards
1.1.1. Why are bacteria useful in biotechnology and genetic modification?
Rapid reproduction rate - chemicals are also produced quickly
Ability to make complex molecules (e.g. turn milk into yoghurt)
Little ethical concerns
Plasmids - using vector carrying foreign genetic material
1.2.2 Discuss why bacteria are useful in biotechnology and genetic modification, limited to the presence of plasmids
Small, circular loops of DNA
Can be an ideal way of transferring DNA from one cell to another during genetic manipulation
2.1. Describe the role of anaerobic respiration in yeast during the production of ethanol for biofuels
Plant material used as the substrate for producing ethanol, (source of glucose) chopped up into small pieces and mixed with yeast
Yeast respires anaerobically and produces ethanol
The liquid is separated from the remaining solids and any water is removed, leaving a concentrated solution of ethanol
2.2. Describe the role of anaerobic respiration in yeast during bread-making
Bread is made from dough, a mixture of flour, water, salt, sugar and yeast, and is kept at a warm temperature
Yeast ferments the sugar, producing carbon dioxide and alcohol (respires anaerobically if it has access to lots of sugar, even if oxygen is available)
Bubbles of carbon dioxide are trapped in the dough and make it rise
When the bread is baked, the bubbles give the bread a “light” texture. Heat causes the alcohol to evaporate, leaving behind the taste of bread
2.3. Describe the use of pectinase in fruit juice
production
Pectinase breaks down pectin, molecules that act like “glue” in cell walls - extracting fruit juices and softening vegetables
Produce a clearer juice as larger polysaccharides like pectin can make the juice seem cloudy - once they are broken down into smaller molecules, the juice becomes clearer
- Cut an apple in half
- Chop each half into small pieces (grater) and put them into separate beakers (chopping before squeezing releases more juice, but does not break open all cells so a lot is lost)
- Pour 10 cm³ of water over the apple in beaker A and 10 cm³ of pectinase solution over the apple in beaker B (pectinase - cell walls break more easily, more juice can be squeezed out)
- Place both beakers in a water bath at 40°C for 20 minutes
- Filter the juice from each of the beakers of apple piece
2.4. Investigate and describe the use of biological washing powders that contain enzymes
Many stains on clothes are organic – oil from skin, protein from blood, fat and protein from food. Detergents that only contain soap can remove some when mixed with hot water, but it takes a lot of time and effort and very high temperatures
Biological washing powders contain enzymes similar to the digestive enzymes produced in the alimentary canal that help to break down large food molecules
Quickly breaks down large, insoluble molecules such as fats and proteins into smaller, soluble ones that will dissolve in washing water
Effective at lower temperatures, less energy (and money) is used - water does not need to be at high temperatures. Can clean delicate fabrics that aren’t suitable for high temperatures
- Add same amount of stain to each piece of fabric and let it dry before you put it into the beakers to “wash”
- Weigh out 3 g of each powder and dissolve each in 500 cm³ of water at 30°C in a beaker
- Add a piece of the same fabric with the same stain to each
- Stir the washing twice over a 10-minute period
- Produce a scale of cleanliness and record results
- Repeat tests to see if you get the same results
(Wear gloves, don’t let washing powders touch skin)
2.5. Explain the use of lactase to produce lactose-free milk
Lactose: complex sugar found in milk
Babies are born with ability to produce lactase, which breaks down lactose, but many lose the ability as they get older. They become lactose intolerant and react badly to the lactose in milk and products made from milk (cheese, yoghurt etc)
Symptoms: nausea, flatulence, diarrhoea - digestive system is upset by the lactose
Milk can be made lactose free by adding lactase to it and leaving it for a while to allow it to break down the lactose. It breaks lactose down into glucose and galactose, simple sugars
One can use test strips to detect the concentration of glucose
2.6.1. Describe how fermenters can be used for the large-scale production of useful products by bacteria and fungi (insulin)
Through genetic modification, the gene for human insulin is inserted into bacteria which then produce human insulin and can be collected and purified for medical use to treat people with diabetes
2.6.2. Describe how fermenters can be used for the large-scale production of useful products by bacteria and fungi (penicillin)
Penicillin was the first antibiotic, discovered when Fleming noticed some bacteria he had left in a Petri dish had been killed by the naturally occurring Penicillium mould
It produces a chemical to prevent it being infected by certain types of bacteria, which was isolated and named penicillin
Cultured in a fermenter, a container used to grow microorganisms like bacteria and fungi in large amounts
2.6.3. Describe how fermenters can be used for the large-scale production of useful products by bacteria and fungi (mycoprotein)
Mycoprotein is a protein-rich food suitable for vegetarians eg. it is used in Quorn™ products
The fungus Fusarium is cultured on an industrial scale in fermenters in aerobic conditions (provided with oxygen) and provided with glucose syrup as a food source (for respiration)
The fungus grows and multiplies in the fermenter. The fungal biomass is harvested and purified to produce mycoprotein
2.7.1. Describe and explain the conditions that need to be controlled in a fermenter (temperature)
Need to ensure optimum environment to increase enzyme activity (denature if too high, too slow if too low)
Monitored using probes
Water jackets maintain temp by removing energy released by fermentation to give constant temperature
Stirring paddles ensure that temperature is evenly distributed
2.7.2. Describe and explain the conditions that need to be controlled in a fermenter (pH)
Need to ensure optimum environment to increase enzyme activity (denature if too high or low)
Monitored using a probe to check it is at the optimum value for the particular microorganism being grown
Adjusted using acids and alkalis
Stirring paddles ensure that pH is evenly distributed
2.7.3. Describe and explain the conditions that need to be controlled in a fermenter (oxygen)
Needed for aerobic respiration to occur (without it yeasts and fungi respire anaerobically to make alcohol)
Air supply provides oxygen
Stirring paddles ensure even distribution and keep the microorganisms suspended so they always have access to it
2.7.4. Describe and explain the conditions that need to be controlled in a fermenter (nutrient supply)
Needed for use in respiration to release energy for growth and to ensure microorganisms are able to reproduce
Fermenter filled with a medium containing required nutrients such as sugars (provide energy for respiration) and ammonium salts (used to make proteins and nucleic acids, DNA and RNA)
Stirring paddles ensure even distribution and keep the microorganisms suspended so they always have access to it
2.7.5. Describe and explain the conditions that need to be controlled in a fermenter (waste products)
Ensures only desired microorganisms will grow
Fermenter cleaned by steam to kill microorganisms and prevent chemical contamination
