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
Product: Simple sugars
How are stains caused by lipids washed out
Source: Butter Oil
Products: Fatty acids and glycerol
How are stains caused by proteins washed out
Source: Blood, Grass
Products: Amino acids
Which washing powder is more effective at lower temperatures?
What pH do biological washing powders work best at
How are enzymes used in food production
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
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
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
What is used to genetically modify plants
Agrobacterium Tumefaciens. Its a pathogen that invades plant cells and inserts its genes into the plants dna
How are plants genetically modified
get a plant that is already resistant to herbicide (or whatever characteristic you need) and work out which gene is responisble
cut the gene out of one of the plants cells
Agrobacterium tumefaciens bacteria contain a circular loop of dna that you remove 'cut open' and insert the gene
alow the agrobacterium tumefaciens to infect cells of the target plant
bacteria will insert their genes into plants dna
these cells are then grown on a medium containg the herbicide, those that grow contain the gene.
How are crops gm to be resistant to insects
the bacterum Bacillus thuringiensis (Bt) produces a toxin that kills insect larvae that are harmful to crops
the gene for Bt is inserted into crops like corn and cotton which then produce the toxin in their stems and leaves
The toxin is specific to insect pests - wont harm humans, animals, or other insects.
long term effects arent yet known
over time insects are likey to become resistant to the toxin so farmers use other insecticides too.
How could biotechnology help in developing countries
Crops can be genetically engineered to be resistant to pests - improving crop yield
crops genetically engineered to grow better in drought conditions - improving crop yield
crops can be genetically engineered to combat certain deficiency diseases
why do people disagree with gm crops in developing countries
argue they are hungry because cant afford to buy food not because there isnt any, should tackle poverty first
fear countries may become dependent on companies who sell gm seeds
poor soil is reason some crops fail so even gm crops wont survive
How could gm plants help in developed countries
heart disease and some cancers are common health problems, gm plants could help with this.
Snapdragon flowers contain type of flaconoid, they are molecules that have antioxidant effects which are thought to protect against cancers and heart disease. scientists have genetically engineered purple tomatoes so they contain the flavonoid gene. so theres an easy way to get antioxidants to people in developed countries that dont eat enough fruit and veg
what are the problems with purple tomatoes
flavonoid may change flavour of tomato
some people are worried about long term effects of GM crops - like how they will affect biodiversity or whether transplanted genes will get out into other plants
What is the problem with the population rising quickly
not everyone has food security
rising popluation means global food production muct increase too so people have enough to eat with the right balance of nutrition (this is food security)
According to United Nations World Food Programme in 2000-02 there were 852 million undernourished people worldwide, of these 815 million lived indeveloping countries
What are the three ways to increase food production
reducing pest numbers
selective breeding programmes
genetically modifying plants
How can we reduce pest numbers
Killing insects and plants means crops grow larger which means productivity is greater
farmers can reduce pest number by using insecticides
some plants are gm to produce toxins
crop rotation (growing a cycle of different crops in a field each year) can stop the pests that affect one particular crop building up in an area
biological control - using living things instead of chemicals to control a pest e.g aphids eat vegetables, ladybirds are aphid predatrs so they can be released to keep numbers down.
How can selective breeding increase food production
selective breeding is when humans select the best plants according to what we want from them, it can be used to develop the desired traits e.g produce a plant that has a very high yield of wheat
works by slecting the parents with the best characteristics, theyre bred with each other, the best offspring are selected and bred, this is repeated over several generations
What are biofuels
Fuel made from plants, animals, or their waste products
What is biogas
microorganisms decompose waste materual or plants to produce biogas
usually about 70% methane and 30% CO2
can be burned to power a tubrine or to heat water and produce steam to heat central heating systems
can be used as fuel for cars and buses
What is biodiesel
alternative fuel similar to regular diesel which can be used in vehicles - you dont need to alter the vehicle much
made from vegetable oils, animal fats or waste cooking oil
What is ethanol
can be burnt as fuel. its a cleaner fuel than petrol or diesel producing fewer pollutants
produced by using yeast to ferment glucose, materials like sugar cane, corn or barley can be used as source
cars can be adapted to run on mixture of ethanol and petrol known as gasohol.
What are the advantages of biofuels
theyre sustainable and renewable - plants that are used can be replaced quickly
clean fuels - less particulates which cause lung disease
no suplfur dioxide/acid rain
What are the disdvantages of biofuels
growing the crops takes up a lot of land so less land for growing food
power stations and wehicles need to be adapted to use biofuels which takes time and money