iGCSE Biology Notes Biotechnology and genetic modification

[q] Bacteria

[a] 

Bacteria are useful in biotechnology and genetic engineering due to their rapid reproduction and their ability to make complex molecules

[q] Bacteria are useful in biotech due to:

[a] 

○ Lack of ethical concerns over their manipulation and growth
○ Genetic code shared with all other organisms
○ Presence of plasmids

[q] Biofuels

[a] 

○ Yeast is a single celled fungus that uses sugar as its food source
○ When it respires, ethanol and carbon dioxide are produced
○ C6H12O6 => 2C2H5OH + 2CO2
○ Yeast can respire anaerobically if it has access to plenty of sugar, even if oxygen is available
■ This is used to make bread
■ The carbon dioxide produced by the yeast during respiration is caught in the dough, causing the bread to rise

[q] Fruit Juice production

[a] 

○ Fruit juice is produced by squeezing the fruits to remove the juice
○ Chopping the fruit up before squeezing helps to release a lot more juice, but this does not break open all the cells so a lot of juice is lost
○ Instead we add pectinase to the chopped up fruit, so that more juice is released
○ Pectinase works by breaking down a chemical called pectin that is found inside plant cell walls
○ Once the pectin is broken, the cell walls break more easily and more juice can be squeezed out of the fruit
○ Adding pectinase to fruits also helps to produce a clearer juice
■ As pectin makes the juice more cloudy

[q] Biological washing powders

[a] 

○ Many stains on clothes are organic molecules
■ Oil from sin, fat and protein from food
○ Detergents that only contain soap can remove some these stains when mixed with hot water,
■ This requires a lot of time and very high temperatures
○ Biological washing powders have enzymes similar to the digestive allowing the stains to be broken down
○ The work at low temperatures and require less energy
○ Can be used to clean delicate fabrics

[q] Lactose-free milk

[a] 

○ Milk can be made lactose free by adding enzyme lactase to it and leaving it to stand for a while to allow the enzyme to break down the lactose
■ Used by people who are lactose-intolerant (unable to produce lactase to digest milk)
● Usually older people
● Can cause diarrhea, nausea and flatulence

[q] Penicillin production

[a] 

○ Penicillin was the first antibiotic to be discovered
○ mould of the fungus penicillium, was able to kill bacteria
■ Thus called penicillin

[q] Fermentation production of penicillin

[a] 

We had to produce it on a large scale
■ So we used a industrial fermenter
● Conditions can be controlled to produce large amounts
■ Fermenters are containers used to grow (culture) microorganisms like bacteria and fungi in large amounts
■ The fermenter has to be clean, nutrients should present, should have optimum temperature, should have optimum pH, should have oxygen, should be agitated (stirring)

[a] 

They are used to produce genetically modified bacteria and penicillium mould that produces
penicillin

[q] Genetic Engineering

[a] 

As changing the genetic material of an organism by removing changing or inserting individual genes

[a] 

■ The insertion of human genes into bacteria
■ The insertion of genes into crop plants to confer resistance to herbicides
■ The insertion genes into crop plants to confer resistance to insect pests
■ The insertion of genes into crop plants to provide additional vitamins

[a] 

■ The DNA making up a human gene is isolated using restriction enzymes, forming sticky ends
■ The cutting of bacterial plasmid DNA with the same restriction enzymes, forming complementary ends
■ Insertion of human DNA into bacterial plasmid DNA using DNA ligase to form a recombinant plasmid
■ Insertion of plasmid into bacteria
■ Replication of bacteria containing Recombinant plasmids which make human protein as they express the gene

[a] 

● Reduced uses of chemicals
● Better for environment
● Increase yield from the crops
● Less time used by farmers

[a] 

● Increased costs of seeds
○ Cost more to develop them
○ Poorer farmers cannot compete with larger farms
● Risk of inserted genes being transferred to wild plants by pollination which could reduce the usefulness of the GM crop
○ If weeds also gain the gene, they will be resistant
● Reduced biodiversity
○ Fewer plant species when herbicides have been used this can impact insects and insect eating birds