Topic 3 - Biotechnology Flashcards
What is biotechnology
using living organisms to produce useful products or to provide people with services
How are microorganisms grown on a large scale
They are grown in fermenters which are big containers full of liquid ‘culture medium’ which microorganisms can grow and reproduce in.
food is provided in the liquid culture medium in the liquid. They need carbohydrates as an energy source, plus nitrates to make protein, vitamins and minerals.
Air is piped in to supply oxygen (if they respire aerobically)
Need to be kept at right temp. Too cold and the growth rate will slow down, too hot enzymes in the microoganisms will denature. They produce heat by respiration so the fermenter must be cooled which is usually done with a water jacket whch cold water is pumped through.
Instrements are used to monitor pH so it is right
Sterile aseptic conditions are needed to prevent contamination
A motorised stirrer keeps the culture well mixed so all microorganisms get the nutrients and oxygen
How can you investigate how different factors affect yeast growth
when yeast respires anaerobically it priduces CO2 and alcohol
boil water in test tube to get rid of any dissolved oxygen
when its cooled dissolve small amount of sugar and yeast in the water
add a layer of parraffin to keep out oxygen
attach a bung with a delivery tube to a test tube containing limewater
count the bubbles produced in a set time to measure rate of CO2 production
use water baths at different temps to see the effect of heat, works best at 37*. Grows slower at lower temps, is killed at temps higher than 48*.
Vary pH of solution, works best 4-4.5
Vary the sugar conc, the higher the conc the faster it grows
What are microproteins and how are they produced?
Used to make meat substitutes e.g Quorn
Made from fungus Fusarium which is grown in fermenters using glucose syrup as food
respires aerobically so needs to be supplied with oxygen
Has healht benefits over meat - contains more proteins and fibre and less fat
How is yoghurt produced?
Bacteria ferment milk
Equipment is steralised to kill any unwanted microorganisms
the milk is then pasturised and cooled
starter culture of lactobacillus bacteria is added and the mixture is incubated (heated to 40*) in a fermenter
bacteria ferments the lactose sugar in the milk to form lactic acid which causes the milk to clot and solidify into yoghurt
flavours and colours are added
how can you investigate the effect of different factors on yoghurt making
add milk to 5 sterile boiling tubes, pasteurise and then cool the milk
add start culture to each and gently stir
incubate for 5 hours at 5 different temps
measure the pH to see how successful it was
pH will be 4 at optimum temp (40*)
pH will be higher at temps lower than 40 because growth rate is slower
pH will stay at 7 at higher temps because it kills bacteria so no yoghurt
What are the advantages of using microorganisms for food production
can grow very quickly. Much quicker than plants of animals
easy to look after, all you need it something to grow them in, food, oxygen and the right temp
can be produced whether climate is hot or cold, so can be grown in places that are unsuitable for farming crops or animals
Microorganisms can use waste products from agriculture and industry as food for life processes which makes it cheaper than other methods
What are biological washing powders
Used to get rid of insoluble chemicals such as starch, proteins and fats
Contain the same chemicals as non-biological but also contain a mixture of enzymes which break down stubborn stains
What happens to stains caused by carbohydrates
source: jam, chocolate
Enzymes: Amylases
Product: Simple sugars
How are stains caused by lipids washed out
Source: Butter Oil
Enzymes: Lipases
Products: Fatty acids and glycerol
How are stains caused by proteins washed out
Source: Blood, Grass
Enzymes: Proteases
Products: Amino acids
Which washing powder is more effective at lower temperatures?
Biological
What pH do biological washing powders work best at
7
How are enzymes used in food production
(Chymosin)
Cheese is made using a substance called rennet which is traditionally obtained from the lining of a calf’s stomach.
it contains the enzyme chymosin which clots the milk
not suitable for vegetarians so chymosin is produced from genetically modified microorganisms
the gene was isolated from calf’s stomach cells and put into yeast cells
How are enzymes used in food production
(Invertase)
Enzyme invertase or sucrase is used in the manufacture of sweets in other foods
converts sucrose into glucose and frctrose which tastes sweeter meaning less sugar is needed for the same sweetness - saving money and allowing manufacturers to produce lower-calorie sweet foods
produced naturally by a yeast called Saccharomyces cerevisiae
How are enzymes made easier to remove
immobilising them
Why are enzymes difficult to remove
they end up dissolved in the mixture with the substrates and products
How are immobilised enzymes used in general
they don’t need to be serparated out from the mixture after the reaction has taken place
they are attached to an insoluble material e.g fibres or theyre encapsulated in alginate beads (gel like substance) the insoluable material with attached enzymes can be washed and reused
Why do we need lactose free milk
The sugar lacotse is naturally found in milk. its broken down in digestive system by the enzyme lactase which produces glucose and galactose. These are absobred into the blood.
Some people lack lactase so if they drink milk the lactose isnt broken down and gut bacteria feed on it causing abdominal pain, wind, and diarrhoea
How is lactose free milk made
Immobilise the lactase: Mix sodium alginate and lactase together in a syringe. Add one drop at a time to beaker of calcium chloride. beads form (the lactase is immobilised in the beads). leave them to harden for a few minutes then use tea strainer to separate them from the solution
Setting up a column of immobilised lactase: Put some nylon gauze in a shyringe and attach a tap to the end. Add the beads.
Making lactose free milk: Use a glucose test strip to see if theres any glucose present in a beaker of milk. Slowly add the milk to the syringe. Collect the treated milk in a small beaker. Test glucose content of treated milk and compare to untreated milk. No glucose before, gucose after because lactase has been converted to glucose.
How is pectinase used to extract apple juice
It breaks down pectin which is found in the cell walls of apples and oranges causing the cell to release its juice.
What is genetic engineering?
Cutting a useful gene out of one organism and pasting it into another e.g human insulin in bacteria
How can bacteria be engineered to produce human insulin
Plasmid is removed from a bacterium
insulin gene cut out of human chromome using a restirction enzyme. restriction enzymes recognise specific sequences of dna and cut the dna at these point, the cute leaves one of the dna strands with unpaired bases called the sticky end.
plasmid is opened using the same restriction enymes - leaving the same sticky ends
plasmid and human insulin gene are mixed together
ligase is added which joins the sticky ends together to produce recombinant dna (two different bits of dna stuck together)
Reconmbinant dna stuck back into bacterium
bacterium grown in fermenter to end up with millions of bacteria that produce human insulin
what does transgenetic mean
contain a gene transferred from another species