Topic 3 - Biotechnology Flashcards Preview

Biology - B3 > Topic 3 - Biotechnology > Flashcards

Flashcards in Topic 3 - Biotechnology Deck (41):

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 COproduction

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?



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

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


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% CO

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 

Carbon neutral

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