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MPW biology > 22 - Cloning and Biotechnology > Flashcards

22 - Cloning and Biotechnology Flashcards

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1
Q

Which type of reproduction is a type of cloning?

A

Asexual reproduction

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2
Q

What is cloning?

A

the production of genetically identical organisms, organs, tissues, cells or DNA molecules

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3
Q

What is vegetative propagation also known as?

A

Natural cloning in plants

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4
Q

What happens in vegetative propagation?

A

A structure forms from a part of the parent plant which is genetically identical to the parent

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5
Q

What are 3 parts of a plant which vegetative propagation can occur from?

A

Leaves, roots, stem

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6
Q

What is vegetative propagation a means of except asexual reproduction?

A

Surviving from one growing season to the next

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7
Q

What do perennating organs enable a plant to do?

A

Survive adverse conditions

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8
Q

What are 4 examples of plant parts where natural cloning occurs?

A
  1. Rhizomes 2. Bulbs 3. Runners 4. Tubers
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9
Q

What is a rhizome?

A

A specialised underground stem which is often used as a food store

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10
Q

What is natural cloning used for in horticulture?

A

Producing new plants

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11
Q

What are 2 advantages of using natural cloning in horticulture?

A
  1. Increases plant numbers cheaply

2. Gives many genetically identical plants

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12
Q

What is often applied to cuttings to promote root growth?

A

Rooting powders

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13
Q

What can be taken from a plant for use in natural cloning?

A

Cuttings

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14
Q

What are 2 advantages of using cuttings instead of seeds to grow new plants?

A
  1. Much faster

2. Guarantees good quality of plants if the parent plant is of good stock

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15
Q

What is the main disadvantage of growing new plants using cuttings?

A

Lack of genetic variation in offspring can have negative impact if a new disease or pest appears

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16
Q

What are 4 plants commonly grown using cuttings?

A
  1. Bananas 2. Cassava 3. Sugar cane 4. Sweet potatoes
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17
Q

What is the most commonly used technique to artificially clone plants?

A

Micropropagation using tissue culture

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18
Q

What is micropropagation?

A

The artificial process of making large numbers of genetically identical offspring from a single parent plant using tissue culture techniques

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19
Q

In what 5 situations would micropropagation be used to grow new plants?

A
  1. When the parent plant doesn’t readily produce seeds
  2. When the plant doesn’t respond well to natural cloning
  3. When the plant is very rare
  4. When the plant has been genetically modified or selectively bred with difficulty
  5. When the plant is required to be pathogen-free
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20
Q

What can scientists in the field use to keep plant tissues sterile during micropropagation?

A

The sterilising tablets used to sterilise drinking water

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21
Q

What is used to sterilise plant tissue in industrial micropropagation?

A

Large sterilising units

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22
Q

What is the material of the shoot tip cut up called?

A

The explant

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23
Q

Why is a plant sterilised using water sterilisation tablets more likely to remain sterile?

A

The chemical doesn’t have to be washed off

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24
Q

What are 2 plant hormones found in the mixture used in micropropagation?

A

Auxins and cytokinins

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25
Q

What is a callus?

A

Mass of identical undifferentiated plant cells

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26
Q

Where does micropropagation now take place?

A

In bioreactors

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27
Q

What are the 6 steps of artificial plant cloning using tissue culture and micropropagation?

A
  1. A small piece of the shoot tip of the desired parent plant is cut off using a sterile scalpel. This will contain meristem tissue. The piece of shoot tip is dissected (cut up) in sterile conditions. The pieces of shoot tip are referred to as explants (meaning tissue removed from a plant).
  2. The explants undergo surface sterilisation, e.g. using dilute bleach, ethanol or UV light. This kills any pathogens present on the surfaces of the cells.
  3. The explants are placed on sterile nutrient agar (containing water, sugars, amino acids, mineral ions etc.). The agar also contains plant hormones (auxin and cytokinins) which will stimulate mitosis.
  4. As the cells in each explant divide repeatedly by mitosis, a mass of undifferentiated cells forms; this is called a callus. The cells in the callus are unspecialised and totipotent (i.e. each cell has the potential to become any type of specialised cell).
  5. Once each callus reaches a critical size (before cells in the centre die from lack of nutrients), it is divided into small clusters of cells. This step can be repeated many times to generate huge numbers of cell clusters, each of which now has the potential to grow into a complete plant.
  6. The cell clusters are transferred onto fresh agar which has a different ratio of auxin to cytokinin. This will stimulate the formation of small shoots from each group of cells.
  7. The hormone ratio is changed again to stimulate root formation.
  8. Multiple tiny ‘plantlets’ have now been produced. Each one is genetically identical to the parent from which the explants were taken. The plantlets should be disease free due to the initial surface sterilisation of the explants and the use of aseptic technique throughout the procedure.
  9. The plantlet can now be transferred from their agar plates into compost in a greenhouse for further growth. There is no further requirement for sterile conditions.
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28
Q

What are 3 possible sterilising agents for use in artificial plant cloning?

A
  1. Bleach 2. Ethanol 3. Water sterilisation tablets
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29
Q

What are 6 arguments for micropropagation?

A
  1. Allows rapid production of good plants
  2. Produces disease-free plants
  3. Can produce viable amounts of plants after genetic modification of plant cells
  4. Can increase numbers of rare plants
  5. Can grow plants which are otherwise quite infertile and difficult to grow from seed
  6. Can produce very large amounts of seedless, infertile plants to meet customer tastes
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30
Q

What are 5 arguments against micropropagation?

A
  1. Produces a monoculture, vulnerable to disease
  2. Relatively expensive and needs skilled workers
  3. Explants and plantlets vulnerable to infection by pathogens during production
  4. If source material infected with virus, all new plants will also have virus
  5. Sometimes large numbers of new plants are lost
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31
Q

What type of animals is natural cloning more common in?

A

Invertebrates

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32
Q

What is an example of how natural cloning can happen in animals?

A

Hydra (related to jellyfish and anemones) grows small offspring as buds from the side of the parent’s body; the offspring detach once they reach a critical size. The offspring are genetically identical clones of the parent Hydra

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33
Q

What is the main form of vertebrate natural cloning?

A

The spontaneous splitting of an embryo into two embryos generates monozygotic (identical) twins.

The twins are genetically identical to each other, but not to an existing adult organism.

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34
Q

How are monzygotic twins formed?

A

The early embryo SPONTANEOUSLY splits to form two identical embryos

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35
Q

Why may monozygotic twins still look different at birth?

A

Differences in positioning and nutrition in the uterus

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36
Q

Which animals can be relatively easily artificially cloned and how?

A

Some invertebrates, for example you can just chop off a bit of starfish to grow a new one

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37
Q

What are the 2 main methods of artificial cloning used in animals?

A
  1. Artificial twinning 2. Somatic cell nuclear transfer
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38
Q

What commercial sector uses artificial twinning?

A

Dairy and livestock farming

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39
Q

What is the principle of artificial twinning?

A

The early embryo is artificially split to produce genetically identical twins
(or quadruplets)

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40
Q

What do you have to do different when doing artificial twinning in pigs and why?

A

Implant a number of embryos into the mother pig as they usually have a litter of piglets, so an individual foetus may be rejected or reabsorbed by the mother’s body

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41
Q

What is the reason for artificial twinning?

A

increase the reproductive output of the most desirable male and female animals, whos gametes are in short supply

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42
Q

Why might some embryos be frozen when doing artificial twinning?

A

You could implant a few unfrozen embryos and assess their success, and if they do well then you can unfreeze and implant the rest

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43
Q

What are the 5 stages of artificial twinning?

A
  1. Select the most desirable male and female animals and collect semen and eggs from these.
  2. Carry out IVF (in vitro fertilisation) to produce zygotes.
  3. Each zygote is allowed to divide a few times by mitosis to produce an embryo. Each embryo is, at this early stage, a ball of totipotent stems cells.
  4. Each embryo is gently pulled into two or four segments.
  5. Each segment, now an embryo in its own right, is implanted into the uterus of a surrogate mother animal, so that pregnancy can proceed.
  6. The animals born will be genetically identical to one another.
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44
Q

What is superovulation?

A

Hormonal treatment to increase number of ovulations

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45
Q

What can you do instead of fertilising the ova within a cow in artificial twinning?

A

Remove the mature eggs from the cow and inseminate them in the lab

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46
Q

Why, in cow artificial twinning, is one embryo implanted per mother?

A

Because single pregnancies are less risky than multiple pregnancies

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47
Q

What type of animal cloning is used to clone an adult animal?

A

Somatic cell nuclear transfer

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48
Q

Why are animals of different breeds used as the cell donor, egg donor and surrogate mother in Somatic Cell Nuclear Transfer?

A

To make it easier to identify the original animal at each stage

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49
Q

What type of cloning was used to produce Dolly the Sheep?

A

Somatic Cell Nuclear Transfer

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50
Q

What is Somatic Cell Nuclear Transfer also known as and why?

A

Reproductive cloning, as live animals are the end result

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51
Q

What are the 8 stages of Somatic Cell Nuclear Transfer?

A
  1. The animal to be cloned is selected. For example, this could be an individual that has particularly desirable, high‐value traits, or one which has undergone successful genetic modification. This animal can be male or female.
  2. A sample of somatic cells is taken from the body of the animal to be cloned. (In the cloning that produced Dolly, cells from the udder were taken.) These are diploid, differentiated body cells. Each of these cells contain the full genome (all the genes) of the animal that is to be cloned.
  3. Meanwhile, eggs are collected from a female animal (referred to as the egg donor). The egg donor should ideally be of the same species as the animal to be cloned; however, if an attempt is being made to clone a very rare (or already extinct!) species, eggs from the most closely related available species could potentially be used.
  4. The eggs have their (haploid) nuclei removed. This is called enucleation of the eggs.
  5. A somatic cell is fused with an enucleated egg cell, with an electrical pulse being applied. This electrofusion step results in the transfer of the somatic cell’s nucleus into the egg. The electrical pulse reactivates all genes in the nucleus. This means that the cell that has been created here (from an enucleated egg plus a somatic cell’s nucleus) essentially becomes a totipotent stem cell.
  6. The cell is allowed is divide a few times by mitosis, growing into an embryo.
  7. The embryo is now transferred into the uterus of a surrogate mother animal so that pregnancy can proceed.
  8. The offspring that is produced is a genetically identical clone of the animal whose somatic cell nucleus was used.
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52
Q

What DNA of a clone produced by Somatic Cell Nuclear Transfer does not come from the original animal which had its nucleus taken?

A

Some mitochondrial DNA comes from the animal which provided the ovum

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53
Q

What are 2 ways in which Somatic Cell Nuclear Transfer is used currently?

A
  1. Pharming 2. Producing GM animals to grow organs for human transplant
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54
Q

What are 3 fields in which animal cloning is currently widely used?

A
  1. Agriculture 2. Animal breeding 3. Medicine
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55
Q

What are 5 arguments for animal cloning?

A
  1. Artificial twinning allows high-yield farm animals to have more offspring
  2. SCNT allows specific good animals to be cloned
  3. SCNT has potential to aid preservation of rare or even extinct animals
  4. Artificial twinning allows the success of a male animal in passing on genes to be determined
  5. SCNT enables GM embryos to be replicated and develop
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56
Q

What are arguments against animal cloning?

A
  1. Scientists have been increasingly convinced that SCNT will not bring back extinct animals
  2. SCNT is a very inefficient process and expensive
  3. Many cloned animal embryos fail to develop properly and produce deformed offspring
  4. Shortened lifespans for many animals
  5. SCNT has been fairly unsuccessful so far in increasing the population of rare animals
  6. illegal for humans
  7. decreases gentic biodiversity, therefore no ability to evolve by natural selection to adapt to changing conditions
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57
Q

What is biotechnology?

A

The industrial use of living organisms (or parts of living organisms, e.g. enzymes) to produce food, drugs or other products useful to humans.

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58
Q

What are 5 examples of biotechnology?

A
  1. Using yeast to make alcohol
  2. Using yeast to make bread
  3. Using fungi to make antibiotics
  4. Using bacteria to clean up oil spills
  5. Enzymes in biological washing powders
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59
Q

What are the main types of organisms used in biotechnology?

A
  1. Prokaryotes - bacteria

2. Eukaryotes - protoctists or fungi

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60
Q

What are 6 reasons we tend to use microorganisms in biotechnology?

A
  1. few ethical concerns
  2. reproduction is usually asexualy therefore genetically identical clones
  3. Can be manipulated easily to do reactions which they wouldn’t naturally
  4. Microorganisms have very short life cycle and grow rapidly, so lots can be grown
  5. Nutrient requirements often simple and cheap i.e. waste materials
  6. Due to simple conditions needed, these too are often cheaper than in non-biological processes
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61
Q

What are 6 disadvantages of using microorganisms in food production?

A
  1. microorgaisms can produce toxins if not at optimum
  2. They are often GM, so concerns about eating it
  3. If conditions aren’t right then the food might not be produced correctly
  4. Often need sterile conditions
  5. Protein has little flavour so needs additives
  6. If large amounts of single-cell proteins are eaten in high quantity, health problems could arise due to high amounts of uric acid when amino acids are broken down.
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62
Q

Describe bread making

A
  1. Yeast (Saccharomyces cerevisiae) is added to a sugar solution, enabling it to respire aerobically (assuming oxygen is present), producing carbon dioxide and water;
  2. The activated yeast is added to bread dough and left in warm conditions; the carbon dioxide produced by the yeast causes the dough to rise (expand);
  3. The dough rises further when the dough is cooked (as the gas bubbles expand at high temperature) but the yeast are now killed.
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63
Q

Describe brewing to produced beer

A
  1. Barley grains are soaked in water; as they begin to germinate, amylase enzymes are produced which break down stored starch into maltose;
  2. Yeast (Saccharomyces cerevisiae) is added and ferments the maltose (i.e. respires it anaerobically) into carbon dioxide and ethanol;
  3. The yeast are killed by pasteurisation (heat treatment);
  4. The beer produced will have an ethanol concentration around 4%.
64
Q

Describe yoghurst production

A
  1. Milk is pasteurised (heat treatment) in order to kill unwanted microorganisms that might already be present;
  2. Specific bacteria are added, e.g. Streptococcus thermophilus, which ferment (anaerbocially respire) the milk sugar lactose to produce lactic acid;
  3. The low pH created causes changes to the structures of proteins in the milk, resulting in the milk thickening into yoghurt and developing a sharp, tangy taste;
  4. The low pH also means that other microorganisms cannot thrive – hence yoghurt can be kept for longer, without going bad, than milk can.
65
Q

What effects do bacteria have on the physical properties of yoghurt and how?

A

Produce extracellular polymers which make yoghurt more smooth and thick

66
Q

Describe cheese making

A
  1. Milk is pasteurised (heat treatment) in order to kill unwanted microorganisms that might already be present;
  2. Specific bacteria are added, which ferment (anaerbocially respire) the milk sugar lactose to produce lactic acid;
  3. The low pH created causes changes to the structures of proteins in the milk, which coagulate (clump together), causing the milk to curdle, i.e. separate into solid curds and liquid whey;
  4. The curds are separated from the whey, strained and pressed to form a solid cheese, which is left to mature;
  5. Many types of cheese have specific fungus added to cause further changes to texture, appearance and flavour as it grows.
67
Q

What is single-cell protein?

A

Edible protein produced by microorganisms

68
Q

What is the best-known example of single-cell protein?

A

Quorn

69
Q

What fungus is used to make Quorn?

A

Fusarium venenatum

70
Q

Is the Fusarium v. fungus itself eaten as Quorn?

A

No, it produces a protein which is combined with egg white to make Quorn

71
Q

What is food security?

A

Having enough food to feed a population, with the population being able to access this food and have a balanced diet

72
Q

What is used as a food source for Fusarium v.?

A

Glucose syrup

73
Q

What 3 types of microorganisms have been used to try to make protein substitutes in the past?

A
  1. Fungi 2. Algae 3. Bacteria
74
Q

What are 2 reasons people argue that more vegetarian diets would increase global food security?

A
  1. Vegetables are cheaper, and therefore more accessible 2. A vegetarian diet is more efficient as it involves fewer trophic levels
75
Q

What are 8 advantages of using microorganisms in human food production?

A
  1. Grow and produce protein fast
  2. High protein content with little fat
  3. Can use a wide variety of waste as food
  4. Can be genetically modified
  5. Can be made to taste like anything
  6. Production is constant on not dependant on weather, breeding cycles etc.
  7. Few ethical concerns
  8. No animal welfasre issues
76
Q

What are 2 examples of medicines produced via biotechnology?

A

Insulin and penicillin

77
Q

What type of microorganism is used to produce penicillin?

A

A mould

78
Q

What are 4 factors which affect how penicillin is grown commercially?

A
  1. Mould is sensitive to pH
  2. Mould is sensitive to temperature
  3. Mould needs rich nutrient medium
  4. Mould needs quite high oxygen levels
79
Q

What are 5 features of the penicillin production process which optimise the rate of production?

A
  1. Buffers in the nutrient medium to keep a constant pH of around 6.5
  2. Relatively small fermenters used as it’s hard to keep larger bioreactors sufficiently oxygenated
  3. Mixture constantly stirred for oxygenation
  4. Rich nutrient medium used
  5. Temperature kept constant
80
Q

What style of manufacturing is used to make penicillin?

A

Semi-continuous batch maufacturing

81
Q

How is penicllin produced?

A
  1. The mould fungus called Penicillium chrysogenum is cultured in a fermenter, of small enough size that the required high oxygen levels can be maintained;
  2. The broth added at the start of the process has very high concentrations of the required nutrients (e.g. sugars, nitrogen source) to allow rapid growth;
  3. To prevent the growth of the fungus being restricted, a pH buffer is used to maintain pH close to 6.5 and a water‐cooled jacket keeps temperature at 26°C, the optimal conditions for the fungal enzymes;
  4. Batch culture method is used, so that there is an initial stage of fast growth (producing a large number of cells that will be capable of antibiotic production), until the nutrients added initially start to run out;
  5. Significant penicillin production only occurs after the main growth phase, probably triggered when nutrient levels drop below a critical point;
  6. The penicillin is secreted from fungal cells into the culture medium, from which it can be extracted and purified.
82
Q

How was insulin extracted before biotechnology?

A

Usually from the crushed up pancreases of pigs or cattle slaughtered for meat

83
Q

What were 4 problems with extracting insulin from the crushed pancreases of dead animals?

A
  1. Some were allergic to animal insulin as was often impure
  2. Some faith groups forbid pig or cow products
  3. Action of animal insulin peaks a few hours after injection
  4. Supply erratic and depended on demand for meat (as animal pancreases usually came from stuff slaughtered for meat)
84
Q

How is insulin produced?

A
  1. Escherichia coli bacteria are genetically modified, i.e. the gene for human insulin is transferred into cells using a plasmid as a vector;
  2. Successfully transformed cells that can synthesise insulin are selected and cultured in a fermenter, in a nutrient broth containing sugars and a nitrogen source;
  3. Oxygen is provided for aerobic respiration and the temperature and pH are controlled to keep these optimal for E. coli’s enzymes;
  4. Continuous culture method is used, meaning that the nutrient levels are constantly topped up (at equivalent rate to that at which they’re consumed): the aim is to maintain the highest possible rate of metabolism and cell division at all times, as this will give the highest yield of insulin in a given time;
  5. Cells are harvested from the culture at regular intervals, allowing extraction and purification of the insulin they have produced;
  6. The insulin is available to diabetics: made in this way, the supply is reliable, it has low cost per dose, is safe to use (not contaminated with viruses) and should be effective in controlling blood glucose (since the insulin produced is the human version of the hormone).
85
Q

What are the 2 approaches to bioremediation?

A

microorganism or plants

86
Q

What is bioremediation?

A

Bioremediation is an example of biotechnology is which the ‘product’ being made is clean air, water or soil: the technique aims to remove pollution

87
Q

What is an example of GM bacteria being used for bioremediation?

A

Bacteria which were genetically modified to break down mercury

88
Q

What are 2 examples of non-GM bacteria being used for bioremediation?

A
  1. Usage in cleaning up oil spills 2. Usage in cleaning up sewage and killing the pathogens contained within it
89
Q

Currently, are GM or non-GM bacteria more successful at bioremediation?

A

Non-GM, although the gap is narrowing

90
Q

Where does bioremediation take place?

A

The removal of pollutants is usually carried out in situ, but there may be cases (for soil in particular) where the material needing decontamination is removed to a processing facility for ex situ treatment, and later returned to its site of origin

91
Q

What is culturing microorganisms?

A

Growing large quantities

92
Q

What are 2 reasons health and safety procedures must always be followed when culturing microorganisms?

A
  1. Even if they are nominally harmless, mutations are always a possibility and could lead to a microorganism becoming pathogenic 2. There may be contamination from pathogenic microorganisms
93
Q

What 4 things do microorganisms being cultured need?

A
  1. nutrients
  2. optimum pH
  3. Enough oxygen
  4. optimum temperature
94
Q

What is the food which is given to cultured microorganisms called?

A

Nutrient medium

95
Q

What are 3 good protein sources which nutrient mediums can be infused with?

A
  1. Blood 2. Yeast extract 3. Meat
96
Q

Do all microorganisms need a precise nutrient balance for their nutrient medium?

A

No, some do but others just need a good source of protein

97
Q

What are the 2 forms a culture’s nutrient medium can be in?

A
  1. Liquid (broth) 2. Solid (agar)
98
Q

What is important about the nutrient medium when culturing microorganisms?

A

That it be kept sterile

99
Q

What do enriched nutrient media allow?

A

Samples containing a small number of organisms to multiply rapidly

100
Q

What are the 4 steps for inoculating broth?

A
  1. Make suspension of bacteria to be grown
  2. MIx known volume with broth in flask
  3. Stopper flask with cotton wool
  4. Incubate at suitable temperature, shaking regularly to oxygenate broth
101
Q

What is inoculating?

A

Adding bacteria to a nutrient medium

102
Q

Why is the flask stoppered with cotton wool when inoculating broth?

A

To prevent contamination from the air

103
Q

What are the 5 steps for inoculating agar?

A
  1. Sterilise inoculating loop by heating until red hot, then make sure it doesn’t touch anything while cooling
  2. Dip loop in bacterial suspension
  3. Remove lid of agar dish and streak the loop across the surface, taking care it doesn’t dig in
  4. Replace lid and loosely hold down with tape
  5. Incubate at suitable temperature
104
Q

What pattern does a bacterial culture’s growth follow?

A

A standard population growth curve

105
Q

What are 5 limiting factors which prevent exponential growth of bacteria?

A
  1. Nutrient availability
  2. Oxygen levels
  3. Temperature
  4. Waste buildup
  5. pH change
106
Q

What are 6 things any microorganism used in any bioprocess must do?

A
  1. Not mutate easily
  2. Not produce poison to contaminate the product
  3. Work reasonably fast
  4. Do the reaction needed
  5. Give a good yield of product
  6. Use quite cheap nutrients and conditions
107
Q

Describe primary metabolites

A

primary metabolites (or the reactions that produce them) are essential for growth;

made during all growth phases (lag, log, stationary and death);

their overall rate of production is in proportion to the population size;

to produce primary metabolites commercially, use continuous culture [see below];

Examples: lactic acid or ethanol (from anaerobic respiration); DNA (from DNA replication); mRNA (from transcription); enzymes and other proteins
(made by translation).

108
Q

What are secondary metabolites?

A

molecules which are only made in significant quantities after the main growth phase;

secondary metabolites (or the reactions that produce them) appear not to be essential for growth in normal conditions;

production may be triggered by nutrient levels falling below a critical threshold, resulting in most production occurring during stationary and death phases;

some may provide an advantage under specific sets of conditions, e.g. antibiotics, which kill competing microorganisms, are only advantageous when nutrients are no longer plentiful;

the functions of many secondary metabolites are unknown, but they are an area of research in the context of drug discovery

to produce secondary metabolites commercially, use batch culture [

Examples: penicillin and other antibiotics (made by fungi to kill competing bacteria).

109
Q

What are 2 of the main ways of growing microorganisms?

A
  1. Batch fermentation 2. Continuous fermentation
110
Q

What are examples of secondary metabolites?

A

penicillin and other antibiotics

111
Q

What are examples of primary metabolites?

A 
lactic acid
ethanol
DNA
mRNA
Enzymes and other proteins (insulin)
112
Q

Describe batch fermentation?

A
  1. Microorganisms inoculated into a fixed volume of medium
  2. As growth occurs, nutrients used up and waste products and biomass accumulate
  3. Culture reaches stationary phase- overall growth ceases, but microorganisms will often carry out biochemical changes to make necessary products
  4. Process stopped before death phase and products harvested
113
Q

Describe continuous fermentation?

A
  1. Microorganisms inoculated into sterile nutrient medium and start to grow
  2. Sterile nutrient medium added continuously to culture once exponential growth reached
  3. Culture broth continually removed, keeping culture volume in bioreactor constant
114
Q

What does continuous culture enable?

A

Continuous log phase

115
Q

Levels of what 3 things are kept more or less constant in continuous fermentation?

A
  1. Nutrients 2. pH 3. Metabolic products
116
Q

What are most bioreactor systems optimised for?

A

Maximum production of metabolites

117
Q

What 2 things can bioreactors be optimised for?

A
  1. Maximum production of biomass 2. Maximum production of metabolites
118
Q

What 2 things is continuous culture used for?

A
  1. Some waste water treatment 2. Production of single-celled protein
119
Q

What type of culture do the majority of industrial processes use?

A

Batch or semi-continuous

120
Q

What is used to separate out the useful stuff from in a bioreactor?

A

Downstream processing

121
Q

All bioreactors produce a mixture of what 5 things?

A
  1. Possibly secondary metabolites
  2. Primary metabolites
  3. Unused nutrient broth
  4. Microorganisms
  5. Waste products
122
Q

What is one of the most difficult parts of the bioprocess?

A

Downstream processing

123
Q

What things are controlled within bioreactors?

A
  1. Nutrients
  2. Asepsis
  3. How well the contents are mixed
  4. Temperature
  5. Oxygen
  6. pressure
124
Q

What are 4 advantages of using isolated enzymes instead of whole organisms?

A
  1. Maximised efficiency 2. Less wasteful 3. More specific 4. Purer product, so less downstream processing
125
Q

What are 4 reasons most isolated enzymes for industrial processes are extracellular?

A
  1. They are easier to get and use than intracellular enzymes as they are secreted 2. Tend to be more robust than intracellular 3. Cheaper than intracellular 4. Most microorganisms produce much fewer extracellular than intracellular enzymes, so they are easier to isolate
126
Q

What are most enzymes used in industrial processes?

A

Extracellular enzymes produced by microorganisms

127
Q

Why are isolated intracellular enzymes sometimes still used?

A

As there are a larger range of them than extracellular enzymes they sometimes provide the perfect enzyme for a particular reaction

128
Q

What are 3 examples of intracellular enzymes used in industry?

A
  1. Asparaginase for cancer treatment 2. Glucose oxidase for food preservation 3. Penicillin acylase for converting natural penicillin into more effective semi-synthetic drugs
129
Q

When might enzymes be lost in an industrial process?

A

If they are free rather than immobilised

130
Q

What is an immobilised enzyme?

A

One which is attached to inert support structure, over which the substrate passes

131
Q

Why are immobilised enzymes an example of technology mimicking nature?

A

In actual cells enzymes are often bound to membranes in a similar fashion

132
Q

What are 5 advantages of using immobilised enzymes?

A
  1. Immobilised enzymes can be reused 2. Enzymes are more easily separated from products and reactants, so less processing 3. More reliable than free enzymes 4. Greater temperature tolerance 5. Greater ease of manipulation
133
Q

What are 4 disadvantages of using immobilised enzymes?

A
  1. Reduced efficiency 2. Higher initial costs of materials 3. Higher initial costs of bioreactor 4. More technical issues
134
Q

What are 4 ways in which enzymes can be immobilised?

A
  1. Surface adsorption to inorganic carriers 2. Covalent or ionic bonding to inorganic carriers 3. Entrapment in a matrix 4. Membrane entrapment in microcapsules or behind a semi-permeable membrane
135
Q

What are 3 advantages of using surface adsorption to immobilise enzymes?

A
  1. Simple and cheap 2. Can be used with a wide variety of processes 3. Enzymes widely available to substrate with virtually unchanged activity
136
Q

What is a disadvantage of using surface adsorption to immobilise enzymes?

A

Enzymes can easily be lost from matrix

137
Q

What are 4 advantages of covalent or ionic bonding to immobilise enzymes?

A
  1. Cost varies 2. Enzymes strongly bound so unlikely to be lost 3. Enzymes very accessible to substrate 4. pH and substrate concentration often have very little effect on enzyme activity
138
Q

What are 2 disadvantages of covalent or ionic bonding to immobilise enzymes?

A
  1. Cost varies 2. Active site of enzyme may be modified in process, making it less effective
139
Q

What is an advantage of using matrix entrapment to immobilise enzymes?

A

Widely applicable to different processes

140
Q

What are 4 disadvantages of using matrix entrapment to immobilise enzymes?

A
  1. May be expensive 2. Can be difficult to entrap 3. Diffusion of substrate to and from active site can be slow and hold up reaction 4. Effect of entrapment on enzyme activity can be variable
141
Q

What are 3 advantages of using membrane entrapment to immobilise enzymes?

A
  1. Relatively simple 2. Relatively little effect on enzyme activity 3. Widely applicable to different processes
142
Q

What are 2 disadvantages of using membrane entrapment to immobilise enzymes?

A
  1. Relatively expensive 2. Diffusion of substrate to and from active site can be slow and hold up reaction
143
Q

What are 6 examples of products made from immobilised enzymes?

A
  1. Semi-synthetic penicillin 2. Fructose (from glucose) 3. Lactose-free milk 4. L-amino acids 5. Glucose syrup (from starch) 6. Plastics
144
Q

How are semi-synthetic penicillin made?

A

Immobilised penicillin acylase used from naturally produced penicillins.

145
Q

How is fructose made?

A

Immobilised glucose isomerase to produced fructose from glucose. Fructose is much sweeter (3x)

146
Q

How is lactose free milk made?

A

Immobilised lactase is used to split/hydrolyse lactose into glucose and galactose

147
Q

How to make L-amino acids?

A

Amnioacylase used to produce pure samples of L-amino acids

148
Q

How is glucose syrup made?

A

Glucoseamylase used to break down starch into glucose syrup. Amylase breaks down starch into small polymers called dextrins. The final breakdown of dextrins to glucose is catalysed by immobilised glucoamylase

149
Q

Describe batch culture in these catagories:
Description

When is it used?

Changes in nutrient levels?

Growth phases occurring?

Overall growth rate?

Degree of technical challenge?

Overall efficiency?

A

Description
Nutrients only added at the start, no topping up of nutrients and no removal of waste

When is it used?
Production of secondary metabolites

Changes in nutrient levels?
Decreases over time and eventually runs out

Growth phases occurring?
lag, log, stationary and death

Overall growth rate?
lower, as log phase is not extended

Degree of technical challenge?
lower, as there is less need to carefully control conditions

Overall efficiency?
Lower, since there is downtime between batches

150
Q

Describe continuous culture in these catagories:
Description

When is it used?

Changes in nutrient levels?

Growth phases occurring?

Overall growth rate?

Degree of technical challenge?

Overall efficiency?

A

Description
Nutrient levels topped up at the same rate they are used, waste is removes and cells can also be harvested during the cultures

When is it used?
to produce primary metabolites or when the biomass of cells is the product

Changes in nutrient levels?
remain high as more are added at the same rate they are used up

Growth phases occurring?
lag and log phse are maintained indefinitely

Overall growth rate?
very high, due to log phase being maintained

Degree of technical challenge?
higher, as conditions must be controlled

Overall efficiency?
higher, since there is no downtime

151
Q

why and how is temperature of fermenters controled?

A

Why
too high = enzyme denature

too low = low enzyme activity

How
thermometer monitors temp
water-cooled heat jacket absorbes excess heat and takes it away
moving paddles which evenly distribute the heat

152
Q

why and how is pH of fermenters controled?

A

Why
too high or too low will reduce the enzyme activity

How
pH probes monitor pH
Buffers can correct changfes in the pH

153
Q

why and how is oxygen concentration of fermenters controled?

A

Why
o2 present = aerobic respiration

o2 absent = anaerboic needed for ethanol production

How
o2 probes monitor the conc of o2
spargers deliver filtered air and disperses it in bubbles

154
Q

why and how is pressue of fermenters controled?

A

why
increases of pressure due to co2 pressure could lead to fermenter exploding

howprssure guages monitor pressure
exhaust pipes allow escpe of excess gasses

155
Q

why and how is nutrient conc of fermenters controled?

A

why
in continuous cultures, the nutrient conc must remain high so the exponential phase is mainntanied

how
nutrient inlet allows nutrietns to be added
paddles keep nutrients evenly distribution and prevents sedementation of cells

156
Q

what is metabolism?

A

all the chemical reactions in an organism’s body.

157
Q

what is a metabolite?

A

metabolite is any product molecule made during the organism’s metabolism

MPW biology (26 decks)

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