Topic 3 - Biotechnology

Question 1

What is biotechnology

Answer 1

using living organisms to produce useful products or to provide people with services

Question 2

How are microorganisms grown on a large scale

Answer 2

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

Question 3

How can you investigate how different factors affect yeast growth

Answer 3

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

Question 4

What are microproteins and how are they produced?

Answer 4

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

Question 5

How is yoghurt produced?

Answer 5

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

Question 6

how can you investigate the effect of different factors on yoghurt making

Answer 6

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

Question 7

What are the advantages of using microorganisms for food production

Answer 7

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

Question 8

What are biological washing powders

Answer 8

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

Question 9

What happens to stains caused by carbohydrates

Answer 9

source: jam, chocolate

Enzymes: Amylases

Product: Simple sugars

Question 10

How are stains caused by lipids washed out

Answer 10

Source: Butter Oil

Enzymes: Lipases

Products: Fatty acids and glycerol

Question 11

How are stains caused by proteins washed out

Answer 11

Source: Blood, Grass

Enzymes: Proteases

Products: Amino acids

Question 12

Which washing powder is more effective at lower temperatures?

Answer 12

Biological

Question 13

What pH do biological washing powders work best at

Answer 13

7

Question 14

How are enzymes used in food production

(Chymosin)

Answer 14

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

Question 15

How are enzymes used in food production

(Invertase)

Answer 15

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

Question 16

How are enzymes made easier to remove

Answer 16

immobilising them

Question 17

Why are enzymes difficult to remove

Answer 17

they end up dissolved in the mixture with the substrates and products

Question 18

How are immobilised enzymes used in general

Answer 18

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

Question 19

Why do we need lactose free milk

Answer 19

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

Question 20

How is lactose free milk made

Answer 20

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.

Question 21

How is pectinase used to extract apple juice

Answer 21

It breaks down pectin which is found in the cell walls of apples and oranges causing the cell to release its juice.

Question 22

What is genetic engineering?

Answer 22

Cutting a useful gene out of one organism and pasting it into another e.g human insulin in bacteria

Question 23

How can bacteria be engineered to produce human insulin

Answer 23

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

Question 24

what does transgenetic mean

Answer 24

contain a gene transferred from another species

Question 25

What is used to genetically modify plants

Answer 25

Agrobacterium Tumefaciens. Its a pathogen that invades plant cells and inserts its genes into the plants dna

Question 26

How are plants genetically modified

Answer 26

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.

Question 27

How are crops gm to be resistant to insects

Answer 27

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.

Question 28

How could biotechnology help in developing countries

Answer 28

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

Question 29

why do people disagree with gm crops in developing countries

Answer 29

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

Question 30

How could gm plants help in developed countries

Answer 30

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

Question 31

what are the problems with purple tomatoes

Answer 31

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

Question 32

What is the problem with the population rising quickly

Answer 32

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

Question 33

What are the three ways to increase food production

Answer 33

reducing pest numbers

selective breeding programmes

genetically modifying plants

Question 34

How can we reduce pest numbers

Answer 34

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.

Question 35

How can selective breeding increase food production

Answer 35

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

Question 36

What are biofuels

Answer 36

Fuel made from plants, animals, or their waste products

Question 37

What is biogas

Answer 37

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

Question 38

What is biodiesel

Answer 38

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

Question 39

What is ethanol

Answer 39

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.

Question 40

What are the advantages of biofuels

Answer 40

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

Question 41

What are the disdvantages of biofuels

Answer 41

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