A Level Biology OCR > Biotechnology > Flashcards

Biotechnology Flashcards

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1
Q

What does biotechnology involve

A

Applying biological organisms or enzymes to synthesis, breakdown, or transformation of materials in the service of people.

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2
Q

What are the advantages of using microorganisms (1)

A

There are no welfare issues to consider - all that is needed are optimum conditions for growth

There is an enormous range of microorganisms that are capable of carrying out many different chemical syntheses or degradations that can be used

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3
Q

What are the advantages of using microorganisms (2)

A

Genetic engineering allows us to artificially manipulate microorganisms to carry out synthesis reactions that they would not do naturally

Microorganisms have a very short life cycle and rapid growth state - if given the right conditions of food, oxygen and temperature huge quantities cna be produced in short periods of time.

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4
Q

What are the advantages of using microorganisms (3)

A

The nutrient requirements of microorganisms are often very simple and relatively cheap and genetic engineering means we can modify them so that they can utilise materials that would otherwise be wasted, making the new microorganisms controlled syntheses much cheaper than industrial processes.

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5
Q

What are the advantages of using microorganisms (4)

A

The conditions which most microorganisms need to grow involve a relatively low temperature, a supply of oxygen and food, and the removal of waste gases making the process very cheap.

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6
Q

What are the disadvantages of using microorganisms (1)

A

If conditions are not ideal it can cause them to not grow properly and so they don’t work efficiently

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7
Q

What are the disadvantages of using microorganisms (2)

A

Conditions that are ideal for microorganisms can also be ideal for harmful microorganisms causing food to go off and so the processes have to be sterile

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8
Q

What is the microorganism and reactants that are required for baking

A

Yeast mixed with sugar and water to respire aerobically. CO2 produced causes the bread to arise

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9
Q

What are the steps in the commercial process of baking (1)

A

The active yeast mixture is added to flour and other ingredients. Mixed and left in warm environments to rise

Dough is kneaded and left to rise again

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10
Q

What are the steps in the commercial process of baking (2)

A

Cooked in a hot oven - CO2 expands and bread rises more - the yeast is also killed during cooking

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11
Q

What are the microorganisms and the chemical processes and conditions that occur during brewing

A

Yeast - respires anaerobically to produce ethanol. Fermentation occurs at 20-23*C, with GM yeasts at lower temperatures —> lower costs, they then clump together and sink leaving the beer clear

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12
Q

What are the steps in the commercial process of brewing (1)

A

Malting - barley germinates producing enzymes that break down starch to sugars which the years uses. Seeds are then killed by slow heating but enzyme activity retains to produce malt.

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13
Q

What are the steps in the commercial process of brewing (2)

A

Malt mixed with hot water and enzymes break down starches to produce wort. Hops are added for flavour and antiseptic qualities. The wort is sterilised and cooled.

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14
Q

What are the steps in the commercial process of brewing (3)

A

Fermentation - Wort inoculated with yeast and temp maintained for optimum anaerobic respiration. Eventually yeast is inhibited by falling PH, build up of ethanol and lock of oxygen

Maturation - beer is conditioned for 4-28 days at temperatures of 2.6*C in tanks

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15
Q

What are the steps in the commercial process of brewing (4)

A

The beer is filtered, pasteurised and then bottled or canned with the addition of CO2

Alcohol content varies between 4 and %

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16
Q

What are the microorganisms and how are they used to make cheese

A

They fed on lactose in milk changing the texture and taste, and inhibiting the growth of bacteria which makes milk go off

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17
Q

What are the steps in the commercial process of making cheese (1)

A

Milk is pasteurised and homogenised

Milk is then mixed with bacterial cultures and sometimes chymasin enzymes and kept until he milk separates into solid curds and liquid whey.

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18
Q

What are the steps in the commercial process of making cheese (2)

A

Cottage cheeses separate the curds from the why and are sold

Most cheeses the curds are cut and cooked in the whey and then strained through a cheesecloth. The whey is used for animal feeds.

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19
Q

What are the steps in the commercial process of making cheese (3)

A

Curds are put into steel or wooden drums and are pressed. They are left to dry, mature and ripen before eating as the bacteria continue to act.

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20
Q

What are the different bacteria and their different purposes in yoghurt making

A

Bacteria - often Lactobacillus Bulgaricus (forms ethanal) and streptococcus themophilus (forms lactic acid) both produce extracellular polymers making yoghurt smooth and thick

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21
Q

What are the steps in the commercial process of yoghurt making (1)

A

Skimmed milk powder is added to the mix and the mixture is pasteurised, homogenised and cooled to 47*C

The milk is mixed in a 1:1 ratio of the two bacteria and incubated at 48*C for 4-5 hours

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22
Q

What are the steps in the commercial process of yoghurt making (2)

A

At the end of fermentation, yoghurt are put into cartons of around 10C, or mixed with sterilised fruit
Thick-set yoghurts are mixed and ferment in the pot
Having a shelf life of 19 days and stored at 2-3C

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23
Q

What is pasteurisation and homogenisation

A

Pasteurisation - heating at 95*C for 20 seconds to kill off most natural bacteria

Homogenisation - Fat droplets distributed evenly through the milk

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24
Q

What is the species name of yeast in baking

A

Saccharomyces cerevisae

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25
What are the advantages of using microorganisms to make food for human consumption (1)
Microorganisms reproduce fast and produce protein faster than animals and plants Microorganisms have a high protein content with little fat Microorganisms use a wide variety of waste materials including human and animal waste reducing waste
26
What are the advantages of using microorganisms to make food for human consumption (2)
Microorganisms can be genetically modified to produce the protein required Production of microorganisms is not dependent on water, breeding cycles etc and can be increased or decreased to match demand Can be made to taste like anything No welfare issues
27
What are the disadvantages of susing microorganisms to produce food (1)
Some microorganisms can also produce toxins if the conditions are not maintained at the optimum Microorganisms have to be separated from the nutrient broth and processed to make the food Need sterile conditions that are carefully controlled adding to costs
28
What are the disadvantages of susing microorganisms to produce food (2)
Often involve GM organisms and many people have concerns about eating GM food The protein has to be purified to ensure it contains no toxin or contaminants Many people dislike the thought of eating microorganisms grown on waste Has little natural flavour and needs additives
29
What is a single celled protein
It is used to develop more of of using micro-organisms to directly produce protein you can eat
30
What is an example of an SCP
Quorn
31
What is penicillin
It was the first effective antibiotic produced by the mould penicillium notatum
32
What was a problem with the penicillin produced from penicillium notatum
The yield is very small and the drug was required in large quantities to treat everyone who needed it until the discovery of penicillium chrysogenum
33
What does P chrysogenum require
High oxygen levels and a rich nutrient medium to grow well. It is sensitive to pH and temperature affecting the way it’s produced commercially —> so a continuos batch process is used
34
What are the stages of production of penicillin
Int he first stage, the fungus grows, int he second stage it produces penicillin, finally the drug is extracted from the medium and purified.
35
What is a feature of the fermenter used to produce penicillin and why
The process uses relatively small fermenters (40-200 dm^3) because it’s very difficult to maintain high levels of oxygenation in very large bioreactors
36
What is the features of the process of producing penicllin
The mixture is stirred continuously to keep it oxygenated There is a nutrient rich medium The growth medium contains a buffer to maintain pH around 6-5 Bioreactors are maintained at about 20-27*C
37
How was insulin produced int he past and what occurred as a result
Insulin was extracted from he pancreas of animals, this meant that the supply was erratic and relied on the demand for meat.
38
What are the negatives of how insulin was produced int he past
Some people were allergic to animal insulin The peak of animal insulin is several hours after eating, making it hard to calculate when to eat meals For some faith groups pig products are not permitted too
39
How is insulin produced now
Genetically engineered is used to produce human insulin The bacteria are grown in a fermenter and downstream processing results in a constant supply of pure human insulin.
40
What is bioremediation
Is when microorganisms are used to break down pollutants and contaminants in the soil or in water
41
What do micro-organisms break down naturally
Organic material producing CO2 and water. Soil and water pollutants are biological. If these organisms are supported they will break down and neutralise many contaminants.
42
Where does bioremediation take place
At the site of contamination
43
What have scientists developed
GM micro-organsims that can break down or accumulate contaminants which they could not naturally encounter e.g mercury
44
Why do scientists need to cultivate microorganisms
For scientific experiments of medical diagnosis of disease
45
What happens whenever microorganisms are cultured in labs and why
The correct health and safety procedures must be followed even when the organisms are expected to be completely harmless. —> As there is always a risk of a mutation taking place making them pathogenic —> There may be contamination with pathogenic microorganisms from the environment
46
What do microorganisms require to reproduce
Food and the right conditions of temperature, oxygen and PH.
47
What is the food that microorganisms have known as
The food provided for this is known as the nutrient medium, this can be in a liquid form (broth) or in a solid form (agar)
48
What is added to the medium
Nutrients to provide a better medium for micro-organism growth Often the medium is enriched with a good source of protein such as blood, yeast extract or meat.
49
Why are these materials added to the medium and what is a feature of the medium
These allow samples to contain a very small number of organisms to multiply rapidly. The nutrient medium must be kept sterile until it is ready to use.
50
What happens once the agar or nutrient broth is prepared
The bacteria must be added in a process called inoculation
51
What are the steps for inoculating a broth
1. Make a suspension of the bacteria to be grown 2. Mix a known volume with the sterile nutrient broth in the flask 3. Stopped the flask with cotton wool to prevent contamination from the air 3. Inoculate at a suitable temperature, shaking regularly to aerate the broth providing oxygen for the growing bacteria
52
What are the steps for inoculating agar (1)
1. The wire inoculating loop must be sterilised by holding it in a Bunsen flame until it glows red hot. It must not be altered to touch any surfaces as it cools to avoid contamination
53
What are the steps for inoculating agar (2)
2. Dip the sterilised loop in the bacterial suspension. Remove the lid of the Petri dish and make a zig-zag streak across the surface of the agar. Avoid the loops dragging into the agar by holding it almost horizontal. However streaks applied must be kept intact.
54
What are the steps for inoculating agar (3)
3. Replace the lid of the Petri dish. It should be held down with tape but not sealed completely so oxygen can get in preventing the growth of anaerobic bacteria. Inoculate at a suitable temperature.
55
What are factors that limit the growth of bacteria in a culture
Nutrients available Oxygen levels Temperature Build up of waste Change in PH
56
What are factors that limit the growth of bacteria in a culture
Nutrients available Oxygen levels Temperature Build of of waste Change in PH
57
What are primary metabolites
Substances that are formed as an essential part of the normal functioning of a microorganisms
58
What are secondary metabolites
When organsims produce substances that are not essential for normal growth but are still used by cells are called secondary metabolites.
59
What occurs in batch fermentation (1)
The microorganisms are inculcated into a fixed volume of medium As growth takes place, nutrients are used up and both new biomass and waste products build up As the culture reaches stationary phase, overall growth ceases but during this phase the microorganisms often carry out biochemical changes to form the desired end products
60
What occurs in batch fermentation (2)
The process is stopped before the death phase and the products harvested The whole system is then cloned and sterilised and a new batch culture started up
61
What occurs in a continuous culture
Microorganisms are inoculated into sterile nutrient medium and start to grow Sterile nutrient medium is added continually to the culture once it reaches the exponential point of growth Culture broth is continually removed - the medium, waste products, microorganisms m and product - keeping the culture volume in the bioreactor constant
62
What does a continuous culture allow for
Continuous balanced growth, with levels of nutrients, pH and metabolic products kept constant
63
What can batch and continuous processes be adjusted to
Ensuring the maximum production of biomass or the maximum production of primary and secondary metabolites for maximum yield
64
What do all bioreactors produce and as a result what has to occur
A mixture of unused nutrient broth, microorganisms, primary and secondary metabolites and waster products. The useful part of the mixture is then separated by downstream processing
65
What is a feature of downstream processing
It one of the most difficult and expensive parts of the whole bio process
66
What are factors that need to controlled in bioreactors (1)
Temperature, as if too low microorganisms don’t grow quickly enough if too high enzymes denature and the microorganisms are inhibited or destroyed Oxygen and nutrient mediums have to be added in controlled amounts, where probes or sample tests indicate the level is dropping
67
What are factors that need to controlled in bioreactors (2)
There are often large volumes of liquid, so as a result simple diffusion alone is not enough to ensure that all microorganisms receive enough food or oxygen so as a result they have a mixing mechanism Bioreactors can be contaminated from the air or by workers - so as a result they are used in sealed, aseptic units
68
DRAW THE POPULATION TIME GRAPH FOR THE GROWTH OF BACTERIA LABELLING THE DIFFERENT STAGES
69
What are the different phases in a population time graph of bacteria (1)
Lag phase - bacteria adapting to their new environment and not yet reproducing at the maximum rate Log or exponential phase - when the rate of bacterial reproduction is close to the theoretical maximum
70
What are the different phases in a population time graph of bacteria (2)
Decline or death stage is when reproduction has ceased and the rate of death of cells is increasing
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