Chapter 21: Biotechnology and genetic modification Flashcards
(12 cards)
Why are bacteria useful in biotechnology and genetic modification?
Due to their rapid reproduction rate and their ability to make complex molecules, the few ethical concerns over their manipulation and growth, and the presence of plasmids
What is the role of anaerobic respiration in yeast during the production of ethanol for biofuels?
We can use plants to make sugars, which yeast then breaks down to make ethanol in anaerobic respiration.
What is the role of anaerobic respiration in yeast during bread-making?
Flour, sugar, water, and salt are mixed with yeast to make dough. Amylase enzymes break down some of the starch to make maltose and glucose, which are used by the yeast in anaerobic respiration. The dough is kept warm and moist, and the yeast ferments the sugar, making bubbles of carbon dioxide which get trapped in the dough and cause the bread to rise. When the bread is baked, the yeast is killed, the alcohol evaporates, and the outer surface hardens
What is the use of pectinase in fruit juice production?
Pectin, a substance which helps to stick plant cells together, is broken down by pectinase, making it easier to squeeze juice from the fruit
Why are biological washing powders that contain enzymes used?
Biological washing powders and liquids contain enzymes that help remove stains. The enzymes are coated with a special wax that melts in the wash, releasing the enzyme. Once the stains have been broken down, they are easier for detergents to remove. The enzymes include proteases, which break down proteins in stains like grass and blood, lipases, which break down stains containing fats and oil, amylases, which break down carbohydrate-based stains like starch, and cellulases, which break down cellulose fibres
Why is lactase used to produce lactose-free milk?
All human babies produce lactase, as milk is their only source of food for the first few months of their lives. Many people lose the ability to produce lactase as they get older, meaning they cannot digest lactose. Therefore, milk can be made lactose-free by binding lactase made from yeast to the surface of alginate beads and passing milk through the beads. The lactose is broken down into glucose and galactose, and the immobilised enzymes are reused.
How are fermenters used for the large-scale production of penicillin?
Penicillin is an antibiotic produced by a fungus called Penicillium. They require proper temperature, pH, oxygen, nutrient supply, and waste products. The stainless steel fermentation vessel consists of PAWS: probes that monitor temperature and pH, air that provides oxygen for aerobic respiration in fungi, water-cooled jacket that removes heat to maintain a temperature of 24 degrees C, and a stirrer that keeps the microorganisms suspended while maintaining an even temperature. Penicillium is added to produce penicillin, they use sugar for respiration and ammonium salts to make protein and nucleic acids. It is then filtered to remove fungus and can be crystallised to make capsules.
What are the conditions that need to be controlled in a fermenter?
Temperature: monitored using probes and maintained using a water jacket, ensures an optimum environment for enzymes to increase enzyme activity and prevent denaturation
pH: monitored using a probe to check that it is at the optimum value for the microorganism being grown, the pH can be adjusted using acids and alkalis
Oxygen: required for aerobic respiration to take place
Nutrient supply: needed for use in respiration to release energy for the growth and reproduction of the microorganisms, such as ammonia, nitrogen, and glucose
Waste products: the contents are filtered to remove waste created by the microorganisms
Define ‘genetic modification’
Changing the genetic material of an organism by removing, changing or inserting individual genes
What is the process of genetic modification using bacterial production of a human protein as an example?
The DNA making up a human gene is isolated using restriction enzymes, forming sticky ends. Plasmids are extracted from bacterial cells, and the bacterial plasmid DNA is cut with the same restriction enzymes, forming complementary sticky ends. The human DNA is inserted into the bacterial plasmid DNA using an enzyme called DNA ligase to form a recombinant plasmid, which is then inserted into bacteria. The bacteria containing the recombinant plasmids multiply, and the human DNA is expressed to make the human protein.
What are some examples of genetic modification?
The insertion of human genes into bacteria to produce human proteins, the insertion of genes into crop plants to confer resistance to herbicides, the insertion of genes into crop plants to confer resistance to insect pests, and the insertion of genes into crop plants to improve nutritional qualities
What are the advantages and disadvantages of genetically modifying crops?
Advantages: reduce crop yield losses as they are not competing with weeds for resources or suffering from pest damage; higher quality of cotton; cheaper/less time-consuming for farmers; less use of chemicals such as herbicides and pesticides, which leads to less pollution, money spent, and risk to workers’ health
Disadvantages: cross-pollination with wild populations reduces genetic diversity and natural biodiversity and risks reducing effectiveness; insect-resistant plants negatively affect pollinators; seeds need to be bought every season, and can be expensive; ethical concerns may arise; some research has shown that plants that have had genes inserted into them do not grow as well as non-GM plants
