Biology, Topic 3

Front 1

What is biotechnology?

Back 1

Biotechnology is the use of living organisms to produce useful products or to provide people with services (e.g. waste management)

Front 2

How are microorganisms grown on a large scale?

a) What are they grown in?

b) What do they need in order to grow?

c) What temperatures are needed/how are they reached?

d) What are the optimum conditions? (Two answers)

Back 2

a) In a culture medium in a large container called a fermenter

b) Carbohydrates (sugars) for energy, nitrates to make protein and vitamins and minerals

c) If it is too cold, the rate of growth slows down but if it is too hot the enzymes will be denatured. Microorganisms produce heat by respiration so a water jacket pipes cold water around the fermenter to cool it

d) The right pH and sterile (aseptic) conditions are needed to prevent contamination

Front 3

What happens when yeast respires anaerobically?

Back 3

It turns sugar into CO2 and alcohol

Front 4

How do you test the rate of CO2 production by yeast in aerobic conditions?

Back 4

1) Boil water in a test tube to get rid of dissolved oxygen

2) When cooled, dissolve sugar and yeast in the water

3) Add a layer of paraffin to keep out oxygen

4) Attach a bung with a tube leading to a test tube of limewater

5) The limewater should go milky when CO2 is present. At this point, count the bubbles of CO2 that go into the limewater from the pipe

Front 5

How would you test the rate of CO2 production under different conditions?

Back 5

Use the same process, but vary the temperature, pH and sugar concentration

Front 6

What is mycoprotein and what is it used for? What are the advantages over normal meat?

Back 6

It is a food made from fungi used to make meat substitutes for vegetarians, such as Quorn. It is healthier than meat as it has more protein and fibre, and less fat

Front 7

How is mycoprotein made?

Back 7

The fungus fuserium is grown in a fermenter using glucose syrup for food, to produce mycoprotein. It respires aerobically so needs to be supplied with oxygen

Front 8

How is yoghurt made from milk? (Five steps)

Back 8

1) The equipment is sterilised to kill unwanted microorganisms

2) Milk is pasteurised (heated to about 70 degrees, then cooled)

3) A culture of Lactobacillus bacteria is added and the mixture is incubated (heated to about 40 degrees)

4) The bacteria ferment lactose sugar in milk to form lactic acid which cause the milk to clot and solidify into yoghurt

5) Flavourings and colours are added before packaging

Front 9

How do you investigate the effect of different factors on yoghurt making? (Five steps)

Back 9

1) Add milk to five sterile boiling tubes, then pasteurise it

2) Add Lactobacillus bacteria and stir gently

3) Incubate each tube at different temperatures

4) To see how successful production was, measure the pH of each tube - as yoghurt is made, pH decreases from pH 7 to pH 4

5) Look at the effect of different variables on yeast growth but keep other variables the same

Front 10

What are the four advantages of using microorganisms for food production?

Back 10

1) They grow quicker than plants and animals

2) They are easy to look after as you only need something to grow them in, food, oxygen and the right temperature

3) It can be produced in hot or cold climates all over the world where areas are unsuitable for crop growth

4) They use waste products from agriculture as food so they are cheaper than other methods

Front 11

What are the two types of stains and how do they wash out?

Back 11

One is caused by soluble chemicals and they wash out in water, but others are caused by insoluble chemicals and have to be washed out using enzyme washing powders

Front 12

What are non-biological and biological washing powders?

Back 12

Non-biological contain chemicals that break up stains.

Biological contain the same chemicals, but also enzymes that break down 'stubborn' stains

Front 13

What do these three things produce when washed out?

a) Carbohydrates

b) Lipid (fats)

c) Protein

Back 13

a) Have amylase enzymes in them which produce sugars

b) Have lipase enzymes in them which produce fatty acids and glycerol

c) Have proteases in them which produce amino acids

Front 14

What are the optimum conditions for biological washing powders?

Back 14

They are most effective at low temperatures and at pH 7 (neutral). Tap water is usually neutral but in some areas may contain calcium so it slightly alkaline and may damage the enzymes

Front 15

How are enzymes used to make cheese?

Back 15

1) Cheese is made using rennet which is obtained from the lining of a calf's stomach. It contains an enzyme called chymosin which clots the milk

2) Vegetarian cheese is made using chymosin from GM microorganisms

Front 16

How are enzymes used to make sweets or other sweet food?

Back 16

1) The enzyme invertase (or sucrase) is used to manufacture sweets as it converts sucrose to glucose and fructose which taste sweeter

2) This means less sugar is needed for the same sweetness so manufactures can save money and make lower calorie sweet foods

Front 17

What happens to enzymes in reactions and how can it be solved for industrial use?

Back 17

In reactions enzymes get dissolved and are difficult to remove, so immobilised enzymes are used as they don't need to be separated from the mixture after the reaction

Front 18

How are immobilised enzymes used?

Back 18

They are attached to an insoluble material or put in beads of alginate (a gel like substance)

Front 19

What can immobilised enzymes be used to make and why?

Back 19

Lactose free milk.

Lactose sugar is found in milk. Lactase breaks it down into glucose and galactose which are absorbed into the blood. Some people lack lactase so lactose isn't broken down and gut bacteria feed on it, causing abdominal pains, wind and diarrhoea (lactose intolerance)

Front 20

How is lactose free milk made?

Back 20

1) Immobilise the lactase by mixing it with sodium alginate. Add this mixture to calcium chloride so that beads form with immobilised lactase in them. Leave these to dry

2) Put some nylon gauze in a syringe and attach a tap to the end and add the beads to the syringe

3) Use a glucose test strip to see if there is any glucose in the milk, then slowly add the milk to the syringe, collecting the treated milk in a beaker. Test its glucose content and compare it with the original milk's

Front 21

What will the glucose test strip show before and after treating milk?

Back 21

Before - won't change colour as there is no glucose

After - it will change colour because the lactose has been converted to glucose (this means that the treatment was successful)

Front 22

What is pectinase used for and how?

Back 22

It is used to extract apple juice. It breaks down pectin in apples causing the cell to release its juice.

Front 23

What is genetic engineering?

Back 23

Cutting out a useful gene from one organism and putting it into another

Front 24

How is the human insulin gene genetically engineered? (Seven steps)

Back 24

1) A plasmid (loop of DNA) is removed from the bacterium

2) The insulin gene is cut from a chromasome using a restriction enzyme which recognises specific DNA and cuts it at the right points

3) The plasmid is cut open with the same enzyme

4) The plasmid and gene are mixed together

5) The enzyme ligase is added to join them

6) This new DNA is inserted into a bacterium

7) The modified bacterium is grown in a fermenter so you have millions of them

Front 25

What are you left with when you use restriction enzymes to cut open a plasmid or a strand of DNA?

Back 25

Sticky ends - unpaired bases at either end of the cut material

Front 26

What is recombinant DNA?

Back 26

It is two different bits of DNA stuck together (for example plasmid DNA and insulin genes)

Front 27

What is a vector used to make genetically modified plants?

Back 27

Agrobacterium Tumefaciens

Front 28

How is bacillus thuringiensis used to make pest resistant plants?

Back 28

1) The gene for a toxin call bacillus thuringiensis is inserted into crops which produce the toxin in their stems and leaves - making them resistant to insect pests

2) The insects that feed on the crops will be constantly exposed to this toxin so they could become resistant to it

Front 29

How could biotechnology help people who don't have enough food?

Back 29

Crops can be engineered to be resistant to pests to improve yield. They can also be engineered to grow better in extreme conditions and some can be made to combat deficiency diseases. (E.g. golden rice has been engineered to produce a chemical that the body turns into vitamin A

Front 30

Why doesn't everyone agree with genetic engineering?

Back 30

Some argue that money is the problem not the amount of food, and that poverty must be tackled first. There are also fears that countries will become dependent on companies who sell GM plants. Sometimes poor soil is the reason crops fail so even GM crops won't help

Front 31

What are purple tomatoes and why have they been made?

Back 31

They are GE tomatoes that contain the flavanoid gene from a snapdragon flower. They are an easy way to give antitoxidants to people who don't eat enough fruit and vegetables.

Front 32

How can you increase food production? (Three ways)

Back 32

1) Reduce pest numbers by killing pests with insecticides, GM crops, crop rotations, biological control (living things)

2) Selective breeding - choosing the best plants for us based on the best characteristics then breeding them with each other

3) Genetically modifying plants

Front 33

What is a biofuel? Name three.

Back 33

Biofuels are fuels made from biomass - plants, animals or their waste products. For example:

- biogas - 70% methane, 30% CO2, used to power turbines or to heat water, or for vehicle fuel

- biodiesel - alternative vehicle fuel made from vegetable oils, animal fats or waste cooking oil

- ethanol - can be burnt as a fuel that produces fewer pollutants than petrol and diesel. Made by using yeast to ferment glucose

Front 34

List four advantages of biofuels

Back 34

1) They are sustainable/renewable

2) They remove CO2 from the atmosphere as the plants they are made from photosynthesise

3) They are clean fuels that produce less particulates than fossil fuels

4) They don't produce sulphur dioxide which causes acid rain

Front 35

List two disadvantages of biofuels

Back 35

1) Growing crops needed to make them takes up space needed for growing food

2) Power stations and vehicles need to be adapted to use biofuels which takes time and money