B3.3 Biotechnology Flashcards
What are most changes to food caused by?
Bacteria and microscopic fungi
How do microorganisms cause changes in food?
They produce enzymes that change the original molecules
What protein does bacteria act on when it turns milk into cheese?
Casein
What is biotechnology?
The alteration of natural biomolecules using science and engineering to produce goods and services
What is a biomolecule?
A substance made by living organisms
What are fermenters?
Big steel vessels in which microorganisms are grown
What fungus is used to produce the antibiotic penicillin?
Penicillium
What is used to sterilise fermenters?
High-pressure steam
Why is steam used to sterilise fermenters?
It is gas so it can reach gaps and corners easily
Why do some fermenters have water jackets?
To take away heat produced from the respiration of the microorganisms
Why is a fermenter sterilised before it’s used?
So that any microorganisms in it before don’t grow instead
What is sterilisation?
The destruction of bacteria, mould, pests and viruses on an object
What are aseptic precautions?
Any methods that ensure that living organisms do not come into contact with something
How do fermenters try to produce as much product as possible in the shortest amount of time?
By trying to supply the microorganism with optimal conditions
What factors are controlled to produce optimal conditions in a fermenter?
- nutrients
- temperature
- pH
- oxygen levels
- agitation
Why is temperature controlled in a fermenter?
To make sure the enzymes in the microorganisms work at a fast rate but don’t get denatured
Why is oxygen provided in fermenters?
So the microorganism can respire aerobically
How is agitation achieved in a fermenter?
By using a stirrer
Why is agitation used in a fermenter?
To mix all the oxygen and nutrients into the culture broth
What could be used as nutrition in a fermenter?
Sources of carbohydrates and nitrogen such as sugar and ammonium ions
What is yeast used for?
- making bread and alcoholic drinks
- in fermenters to produce enzymes and medicines
What happens if the pH of a yeast culture is too acidic or alkaline?
It doesn’t function properly and could die
How can you monitor the growth and activity of a yeast culture?
By measuring the amount of carbon dioxide it gives off
What is mycoprotein made from?
A fungus called Fusarium
Why is there no stirrer for the fermenter used for the production of mycoprotein?
It would tangle and break the hyphae fibres
What is mycoprotein used for?
Producing a protein rich food replacement for meat
Why is the Fusarium used to make meat substitutes?
It is made up of tiny fibres called hyphae that mimic meat’s texture
Why are the hyphae heated during the production of mycoprotein?
To remove a bitter tasting substance they contain
Why are hyphae dried, chilled and pressed during the production of mycoprotein?
To form a fibrous substance that is similar to the texture of meat
What are the advantages of producing food from microorganisms instead of growing crops and keeping animals?
- they grow faster than crops or animals
- easy to handle and manipulate
- take up less space
- can be grown in any part of the world
- can often be grown by using waste materials from other processes as their food source
What does Fusarium use as its food source?
The waste material from the production of flour from wheat grains
What causes broth to move in the fermenter during the production of mycoprotein?
Rising bubbles
Why is it better for heart disease patients to eat mycoprotein instead of meat?
It contains no saturated fat
What does eating mycoprotein instead of meat reduce the risk of?
- heart disease
- type II diabetes
Why does eating mycoprotein instead of meat reduce the risk of type II diabetes?
The high fibre content slows down the rate at which glucose is absorbed from it, which means the blood glucose concentration doesn’t rise rapidly after a meal. This means that insulin isn’t secreted so quickly or in such large amounts which is what is thought to contribute to increasing the risk of type II diabetes
What bacteria is yogurt made from?
Lactobacillus bulgaricus
What is lactose?
The sugar found in milk
What do the yogurt producing lactobacillus bulgaricus live on?
Sugars (lactose) in milk
What does lactobacillus bulgaricus convert lactose to?
Lactic acid
What type of respiration does the lactobacillus bulgaricus undergo?
Anaerobic
What factors affect the type and speed at which yogurt is produced?
- type of bacteria used
- type of milk used
- levels of nutrients within the milk
- temperature
- pH
What are enzymes?
A protein produced by living organisms that acts as a catalyst
How do you produce invertase?
By cultivating a yeast called Saccharomyces cerevisae in fermenters
What does invertase do?
Convert sucrose to glucose and fructose
What is another name for invertase?
Sucrase
Why is sucrose converted to glucose and fructose?
- They are sweeter than sucrose so less is needed
- good for making soft-entered sweets
What types of enzymes do biological washing powders contain?
Proteases and lipases
What do proteases do?
Break down proteins
What do lipases do?
Break down fats
Where is chymosin found?
Calves’ stomachs
What enzyme causes milk to separate into curds and liquid whey?
Chymosin
What are curds?
A semi solid mix of protein and fat
What happens to curds in order to produce cheese?
They are pressed
Why is most chymosin produced from genetically modified yeast?
- it’s easier and cheaper to produce in large quantities
- makes a lot of cheese suitable for vegetarians
What is genetic modification?
The addition of a gene from one organism to another so that the second organism gets the same characteristic
What is recombinant DNA technology used for?
Making a genetically modified organism
What is a restriction enzyme?
An enzyme that cuts DNA molecules into pieces
What are sticky ends?
A few unpaired bases left over from the staggered cuts of restriction enzymes on double stranded DNA
What is DNA ligase?
An enzyme that joins two molecules together
How is insulin making bacteria produced?
- DNA from a human cell that produces insulin is cut into pieces using restriction enzymes to leave sticky ends
- the same thing happens to plasmids found in the bacterial cell
- the sticky ends from the human DNA and the plasmid are linked together in a continuous circle by an enzyme called DNA ligase
- the plasmid is reinserted into the bacteria where it can reproduce in a fermenter
What enzyme breaks down lactose into glucose?
Lactase
What happens when people stop producing lactase?
They become lactose intolerant
What does it mean when an enzyme is immobilised?
It is trapped on or in an inert material
How can you produce beads of immobilised enzymes?
You mix it with sodium alginate, and then add drops of this solution to calcium chloride solution
Why are enzymes immobilised?
So that they can be reused multiple times
What food products are enzymes used in the production of?
- vegetarian cheese
- sweets
- baby food
- fruit juice
What enzymes are used in the manufacture of fruit juice?
Cellulose and pectinase
What are the advantages of using enzymes in the production of food?
- speeds up the production
- makes it cheaper to buy
What does pectinase do?
Separate plant cells from each other
What does cellulase do?
Break down cell walls
Why is pectinase and cellulase used in the production of fruit juice?
Because it means more juice can be extracted
What produces cellulase?
Microorganisms found in the digestive systems of cows
Why do cows produce cellulose?
To digest the cell walls of grass
What is developed to help the global food security crisis?
New varieties of crops with higher yields
What is global food security?
The ability to produce enough food in the future to feed everyone in the world
What is conventional breeding?
The production of offspring by using the natural technique of cross-breeding
How is a very high-yielding crop produced from conventional breeding?
- one high-yielding crop is crossed with another
- all the seeds are sown and allowed to turn into plants
- the plants producing the most grain are selected and cross bred together again
- this is repeated for at least 20 generations
What can crops be lost to?
Pests and fungal diseases
What system is used to combat pests when growing plants?
Integrated Pest Management (IPM)
What are two ways of combating pests during the production of crops?
- developing more resistant plants
- IPM
What transfers viruses to plants?
Aphids
Why is crop rotation used?
It helps prevent the build-up of soil pests for each crop
What are biofuels?
Fuels made by or from living organisms
What does it mean when a fuel is renewable?
It can be made again and again
How is biofuel carbon neutral?
The carbon dioxide released when the fuels are burned balance out because the plants took in carbon dioxide for photosynthesis
How can you get rid of pests?
- you make the environment more attractive to their predators
- chemicals produced from the plant are put into traps to lure the pests into a soap solution, killing them
- pesticides
What are flavonoids?
Pigments found in plants
Why aren’t seeds from GM plants used outside of the country they were developed in?
- they’re expensive
- might not be adapted to climate
- might not be adapted to soil
What is a transgenic organism?
An organism that has had genes transferred from another organism
What is the name of the vector commonly used to produce transgenic plants?
Agrobacterium tumefaciens
How are transgenic plants created from the agrobacterium tumefaciens?
- a gene for the required characteristic is inserted into the plasmid
- the plasmid is reinserted back into the agrobacterium tumefaciens
- plant leaf discs are infected with the bacteria so that the gene is inserted into the plant’s DNA
- the leaf discs will then grow into whole new plants containing that gene
What bacterium produces Bt toxin?
Bacillus thuringiensis
What is Bt toxin?
A substance which is poisonous to insects
Where are bacillus thuringiensis normally found?
Soil
What are the benefits of making plants produce Bt toxin?
- less insecticide has to be sprayed on the crop which reduces damage to the environment
- higher yields are produced as less of the crop is lost to pests
What are the disadvantages of making plants produce Bt toxin?
- it kills other harmless insects such as butterflies and bees needed for pollination
- might cross-pollinate wild plant species
- many insect populations have developed a resistance to the toxin
