6.4 Cloning and Biotechnology Flashcards
(212 cards)
1
Q
Define clone.
A
Genetically identical organisms or cells.
2
Q
Define vegetative propagation?
A
Reproduction from vegetative parts of a plant- usually an over-wintering organ.
3
Q
What are clones produced by?
A
Clones are produced by asexual reproduction in whihc the nucleus is divided by mitosis.
4
Q
What does mitosis produce?
A
Mitosis creates 2 identical copies of DNA, which are separated into 2 genetically identical nuclei before the cell divides to form 2 genetically identical cells.
5
Q
What differences do 2 cells produced from mitosis have?
A
These cells may not be physically or chemically identical as, after division, they may diffrentiate to form 2 different types of cell.
6
Q
What is produced when an organism reproduces asexually?
A
A clone.
7
Q
Give 2 examples or organisms that reproduce asexually?
A
Both single-celled yeasts reproduce by budding and bacteria reproduce by binary fission. Both processes involve exact replication of DNA, so the cells produced are genetically identical.
8
Q
How is an offspring produced by cloning identical to the parent?
A
They’re genetically identical.
9
Q
What are the advantages of reproduction by cloning?
A
- If conditions for growth are good for the parent, they will be good for the offspring.
- Cloning is relatively rapid- so the population can increase quickly to take advantage of the suitable enviromental condiations.
- Reproduction can be carried out , even if there is 1 parent and sexual reproduction is not possible.
10
Q
What are the disadvantegs for cloning?
A
- The offspring may become overcrowded.
- There will be no genetic diversity(except that caused by mutation during DNA replication).
- Population shows little variation.
- Selection is not possible.
- If the enviroment changes to be less adventageous, the whole population is susceptible.
11
Q
How is the differentiation of plant and animal cells different?
A
The differentiation of many plant cells is not as completer as in animals.
12
Q
Why are plants able to reproduce by cloning?
A
Many parts of a plant contain cells that retain the ability to divide and to differentiate into a range of different cells.
13
Q
What process does natural cloning involve?
A
Vegetative cloning.
14
Q
What is vegetative cloning?
A
The is the process of reproduction through vegetative parts of the plant, rather than through specialsed reproductive structures.
15
Q
What are the stems called on a plant that grow horizontally and can grow roots?
A
- Runners or stolens if they grow on the surface of the ground.
- Rhizomes if they grow underground.
16
Q
How are some rhizomes adapted?
A
Some rhizomes are adapted as thickened over-wintering organs from which one or more new stems will grow from in the spring.
17
Q
What is the new stem that grows from a root of another plant called?
A
Suckers
18
Q
What is a sucker?
A
New stems that grow from a plants root. In all cases, the orginal horizontal branch will die, leaving the new stem as a separate individual.
19
Q
What is an over-wintering mechinism for many perennial monocotylendonous plants?
A
Bulbs.
20
Q
For what sort of plant are bulbs an over-wintering mechanism for?
A
perennial monocotylendonous plants.
21
Q
What does a bulb consist of?
A
They consist of an underground stem which grow from a series of underground bases. There is also an apical bud, which will grow into a new plant in the spring.
22
Q
How many apical buds does a bulb contain.
A
Bulbs often contain more than one apical bud and both will grow into a new plant.
23
Q
What is the difference between a corm and a bulb?
A
Corms are solid while bulbs are fleshy.
24
Q
What is a corm?
A
A corm is an underground stem with scaly leaves and buds.
25
How many plants will a corm produce?
A corm will produce 1 or more new plants.
26
What plants reproduce using corms?
* Croci
* Gladioli
27
How does a Kalanchoe plant reproduce asexually?
Clones hrow on the leaf margins. The immature plants drop off the leaf and take root.
28
What is a tuber?
A tuber is a type of underground stem. Potatoes are tubers. One tuber will grow into 1 or more plants. Each new plant can then produce many new tubers for later that year.
29
What are some examples of vegetative parts of a plant?
* Bulbs
* Corms
* Tubers
30
When do mammals clone?
When **identical twins** are formed. This occurs when a fertilised egg (zygote) divides as normal, but the 2 daughter cells then split to become 2 separate cells. Each cell grows and develops into a new individual.
31
What animals commonly reproduce asexually to produce clones?
* Water flea (*Daphnia pulex*)
* Greenfly (*Acyrthosiphon pisum*)
32
Define micropropogation?
Growing large numbers of new plants from **meristem tissue** taken from a sample plant.
33
Define tissue culture.
Growing new tissues, organs or plants from certain tissues cut fro a sample plant.
34
What is the easiest way to create clonmes of a plant?
Through taking cuttings.
35
How would you take a cutting of a plant.
**Cut between 2 leaf joins (nodes).** The cut end of the stem is then placed in moist soil. New roots will grow from the tissues in the the stem-usually from the node, but may grow from other parts of the buries stem.
36
How can it be made easier to get a cutting to root?
* Dipping the end of the cut stem in rooting hormone helps to stimulate root growth.
* Also helpful to wound or **remove the bark from the cut** end of the stem as this encourages the plant to produce callus.
37
What parts of a plnt can a cutting be made from?
* **Root cutting**, in which a section of the root is buried kust below the soil surface, and produced new shoots.
* **Scion cuttings**, which are dormant woody twigs.
* **Leaf cuttings**, in which a leaf is placed on moist soil. The leaves gevelop new stems and new roots. Some leaves may produce many new plants from one cutting.
38
What are some disadvantages of taking cuttings?
The process can be time-conduming and can take up a lot of space. Also some plants do not responf well to taking cuttings.
39
How are many houseplants commercially clones?
Via tissue culture techniques.
40
What is tissue culture?
Tissue culture is a series of techniques used to grow cells, tissues or organs from a small sample of cells or tissue.
41
How is tissue culture carried out?
Tissue culture is carried out on a nutrient medium under sterile conditions.
42
During tissue culture, how can cells be encouraged to differentiate?
CElls can be encouraged to differentiate by the application of plant growth substances at the correct time.
43
What is tissue culture widely used in commercially to increase the number of new plants?
Tissue culture is used in micropropogation.
44
What does micropropogation involve?
It involves taking a small piece of plant tissue (the explant) and using growth substances to encourage it to grow into a whole new plant.
45
What are the steps of micropropogation?
* Suitable plant material is selected and cut into small pieces. These are called explants. Explants could be tiny pieces of leaf, stem , root or bud. Meristem tissue is often used, and this is always free from virus infection.
* The explants are sterilised using using dilute bleach or alcohol. This is essential to kill any bacteria and fungi, as these would thrive in conditions to help the plant grow well.
* The explants are placed on a sterile growth medium (usually agar gel) containing suitable nutrients such as glucose, amino acids and phosphates.
* The gel also contains high concentrations of the plant growth substances auxin and cytokinin. This stimulates the cells of each explant to divide by mitosis to form calllus (a mass of undifferentiated, totipotent cells).
* Once a callus is formed, it is divided to produce a larger number of smaller clumps of undifferentiated cells.
* These small clumps of cells are stimulated to grow, divide and differentiate into different plant tissues. This is achieved by moving the cells to different growth media. Each medium contains different ratios of auxin and cytokinin.
* Once tiny plantlets have been formed, these are transferred to a greenhouse to be grown in compost or soil and acclimatised to normal growing conditions.
46
In micropropogation, what is the small piece of plant tissue used called?
The explant
47
In micropropogation, what does the agar gel contain to promote the cells to expand to divide by mitosis to form callus?
High concentrations of auxins and cytokinins.
48
What is callus?
A mass of undifferetiated, totipotent cells.
49
What is totipotent?
Stem cells that are able to differentiate into any type of cell.
50
In micropropogation how do they get clumps of cells to grow, divide and differentiate into different plant tissues?
By moving the cells to different growth media- each media contains different ratios of auxin and cytokinin.
51
In micropropogation, when stimulating clumps of cells to grow, divide and differentiate into different plant tissues, what does the first medium the plant is put in contain? What does his cause?
It contains the ratio 100 auxin:1 cytokinin and this stimulates roots to form.
52
In micropropogation, when stimulating clumps of cells to grow, divide and differentiate into different plants tissues, what does the second medium the plant is put in contain? What does this contain?
It contains the ratio 4 auxin : 1 cytokinin, which stimulates the shoots to form.
53
What are the advantages of artificial cloning?
* Cloning is a relativley rapid method of producing new plants compared to growing plants from seed.
* Cloning can be carried out where sexual reproduction is not possible.
* The plants selected will be genetically identical to the parent plant.
* If the original plant had an unusual combination of characteristics due to selective breeding or genetic modification, then this combination can be reunited without the risk of losing that combination through sexual reproduction.
* New plants will be uniform in their phenotype.
* Using the apical bud (meristem) as an explant for tissue culture ensures plants are free from viruses.
54
In artificial cloning, why is the fact cloning can be carried out where sexual reproduction is not possible an advantage?
Plants that have lost their ability to breed sexually can be reproduced. Plants that are hard to grow from seed can be reproduced.
55
In artifcial cloning, why is it an advantage that plants selected will be genetically identical to the parent plant?
They will display the same desirable characteristics such as a yield, resistance to a common pest or disease, or a particular colour of flower.
56
What are the disadvantages of artificial cloning?
* Tissue culture is labour intensive.
* It is expensive to set up facilites to perform tissue culture successfully.
* Tissue culture can fail due to microbial contamination
* All the cloned offspring are genetically identical and are therefore susceptable to the same pests and diseases.
* Crops are grown in monocultures allow the rapid spread of a disease or pest between closely planted crop plants.
* There is no genetic variation, except that introduced by mutation.
57
How could you carry out an investigation on cloning cauliflower?
* Cut a mini-flouet from a cauliflower. Cut the floret into small 3-5mm piece, these are the explants.
* Transfer the explants to a sterilising solution, such as sodium dichlorisocyanurate and swirl the solution peridically.
* After 15mins, transfer the explants onto a sterile nutrient agar surface in a specimin tube. Use aseptic techniques to avoid contamination.
* Incubate in a warm lab. Growth and greening of some tissues should be visable within 2 weeks.
58
Define embryo twinning?
Splitting an embryo to create 2 genetically identical embroys.
59
Define enucleation?
Removal of the cells nucleus.
60
Define somatic cell nuclear transfter?
(SCNT) is a technique that involves transferring the nucleus from a somatic cell to an egg cell.
61
What can most cloning in animals be described as?
Artifical
62
What does successful cloning start with?
Totipotent cells.
63
Where can totipotent cells be found in animals?
Only truy totipotent cells are found in very early embryo cells.
64
What does reproductive cloning produce?
Reproductive cloning produces a large number of genetically identical animals.
65
What is reproductive cloning useful for?
* **Elite farm animals** produced by selective breeding or genetic modification. e.g. a good bull can supply sperm for artificial insemination.
* **Genetically modified animals** developed with unusual characteristics.
66
What are the 2 main tyechniques used to achieve reproductive cloning?
* Embryo twinning
* Somatic cell nuclear transfer (SCNT)
67
How does the process of embryo splitting for reproductive cloning taje place?
1. A zygote is created by ***in vitro* fertilisation** (IVF)
2. The zygote is allowed to divide by mitosis to form a small ball of cells.
3. The cells are separated and allowed to continue dividing.
4. Eacxh small mass of cells is placed into the uterus of a surrogate mother.
68
What is embryo splitting used for?
The techniche has been used to clone **elite farm animals or animals for scientific research**.
69
What will the offsprings phenotype and genotype be like for an animal that has undergone embyo splitting?
The precise genotype and phenotype of the offspring will depend of the egg and sperm used. So, **the precise phenotype will be unknown untill the animals are unkown**.
70
What is trhe diagram showing?
Embryo splitting
71
What is the only way to clone an adult?
Somatic cell nuclear transfer (SCNT).
72
What is the advantage of SCNT?
The **phenotype** is known before cloning starts.
73
What mammal was the process SCNT first used on?
In 1996, to produce dolly the sheep.
74
How does somatic cell nuclear tansfer occur?
1. An egg is obtained and it's nucleus is removed, known as **enucleation**.
2. A normal body cell (**somatic cell**) from the adult to be clones is isolated and may have its nucleus removed.
3. The complete adult somatic cell or its nucleus fused with the empty egg cell by applying an **electric shock**.
4. The shock also triggers the egg cell to start developing as though it had been fertilised.
5. The cell undergoes **mitosis** to produce a small bundle of cells.
6. the young embryo is placed into the uterus of a **suragte mother**.
75
What does the diagram show?
Somatic cell nuclear transfer (SCNT).
76
What is non-reproductive cloning?
Non-reproductive cloning is the production of cloned cells and tissues for other purposes than reproduction.
77
What is an example of non-reproductive cloning?
Theraputic cloning.
78
What is achieved through theraputic cloning?
New tissues and organs can be grown as replacement parts for poeple who are not well.
79
What are some examples of tissues and organs that can be grown via theraputic cloning?
* **Skin** can be grown in vitro to act as a graft over burned areas.
* **Cloned cells** have been used to **repair damage** of the spinal cord of a mouse to restore the capability to produce insulin to the pancreas.
* There is the potential to grow **whole organs** to replace diseased organs.
80
What is an advantage of using a patients own cells for theraputic cloning?
Glowing tissues from a patients own cells will mean the **tissues will be genetically identical and so avoid rejection** , which is a problem when transplanting donated organs.
81
What can clonong genetically identical embroys be used for in scientific research?
Research into the action of genes that control develpoment and differentitation. They can also be used to grow specific tissyes or organs for use in tests on the effects of medicinal drugs.
82
What are the 6 arguments for artificial cloning in animals?
* Can produce a whole **herd** of animals with a **high yeild** or that show an unusual characteristic.
* Produces genetically identical copies of very **high value** individuals retaining the same characteristics.
* using genetically identical embryos and tissues allows the effects of genes and hormones to be assessed with no interference from different genotypes.
* **Testing medicinal drugs**, avoids testing animals or humans.
* Produces **tissues identical** to the donor.
* Individuals from an **endangered species** can be cloned to incerase numbers.
83
What are 6 arguments against artificial cloning in animals?
* **Lack of genetic variation** may expose a herd to pests.
* Animals may be produced with little regard for their **wellfare**.
* The **success rate** of adult cell cloning is very poor and the methird is a lot more expensive than conventional breeding.
* Clones may be **less healthy** and have a shorted lifespan.
* There are **ethical issues** regarding how long the embryo survives and weather it is right to create a life then destoy it.
* It does not increase **genetic diveristy**.
84
Define biochenology?
biotechnology is the use of living organisms or part of living organisms in an industrial process.This could be to produce food, drugs or other products.
85
What does biotechnology inculde?
* Domestication of animals
* Planting of crops
* Mechanism or agricutural processes and selective breeding of plants and animals over many generations.
86
What is the oldest doctumented example of biotechnology?
the production of beer or ale 7000 years ago.
87
What are examples of recent uses of biotechnology?
* Use of the bacterium *Clostridium acetobutylium* to produce acetone, which was needed to make explosives during WW1.
* The manufacutre of penecillin from the fungus *Penicillium notatum* during WW2.
88
What shift has been seen in tghe use of biotechnology recently?
It has shifted away from the manufacture of food and towards drugs.
89
What has bought the development of biotechnology to where it currently is?
New science of DNA technology.
90
What has lead to a recent huge expansion of biotechnology?
Out increasing understanding of genetics and genetic engeneering, along with the abilityto manipluate the living conditions of a living organism.
91
What is the biggest expansion of biotechnolgy we have experinced?
The use of microorganisms.
92
What are the 4 main areas in which microorganisms are used in biotechnology?
* Food
* Pharmacetical drugs
* Enzymes
* Other products
93
What are 5 examples of where miroogranisms are used in biotechnology to make food?
* Ethanol in beer and wine.
* Carbon dioxide used to make break rise.
* lactic acid used to make chese and yoghurt.
* Mycoprotein- a filamentous fungus protein to make vegetairian food.
* Soya- soya beans are fermentaed to produce soy sauce.
94
What microorganisms are used to produce ethanol in beer and carbon dioxide in bread?
Yeast (*S. cerevisea*)
95
What microorganism is used to produce lactic acid in cheese and yogurt?
*Lactobacillus* bacteria
96
What microorganism is used to ferment soy beans?
Yeast or *Aspergillus*
97
What are 3 examples of where miroogranisms are used in biotechnology to make pharmacutical drugs? What microorganisms are used?
* Penicillin
* other anitbiotics
* Insulin, other theraputic human proteins.
*Penicillum* fungus is used.
98
What are 7 examples of where miroogranisms are used in biotechnology to make enzymes?
* **Protease** and lipase in washing powder.
* **Pectinase** used to extact juice from friut.
* **Sucrase** used to digest sugar to make food sweeter.
* **Amylase** to digest starch into sugar to produce syrup used as sweetner in food production.
* **Protease** used to tenderise meat.
* **Lactase** used to make lactose free milk.
* Removong sticky residuals from recycled paper.
99
What are 3 examples of where miroogranisms are used in biotechnology to make other products?
* Biogas- combination of carbon dioxide and methane.
* Citric acid- food preservative.
* Bioremediation.
100
What microorganism is used to the production of protease and lipase in washing powders?
Bacteria, e.g. *Bacillus licheniformis*
101
What microorganism is used to the production of pectinase to extract juice from fruit?
*Aspergillus niger*
102
What microorganism is used to the production of Sucrase used to digest sugar to make food sweeter?
Yeasts and *Aspergillus* spp
103
What microorganism is used to the production of amalyse to digest starch into sugar to produce syrup?
A. oryzae
104
What are the advantages of using microorganisms in biotechnology?
* Cheap and easy to grow.
* Takes place at lower temps than chemical engineering.
* Production is not dependant on climate.
* Can be fed by-products from other industries.
* Short life cycle and reproduce quick.
* Microorganisms can easily be genetically modified.
* Few ethical considerasions.
* Products released i to surrounding medium.
* product is more pure compared to conventional chemical engineering.
*
105
What organisms decides microorganisms are used in biotechnology?
Genetically modified mammals. e.g. sheep, goats and cows can be used to produce useful proteins.
106
How have some goats been genetically modified?
To possess the gene for spider silk to sectrete into theor milk.
107
How have some cows been genetically modified?
To synthesis human antobodies, which can be isoloated from their blood.
108
What are other forms of biotechnology?
* Gene technology
* Genetic modification and gene therapy
* selective breeding
* Cloning by embryo-splitting and micropropogation
* The use of enzymes in industrial processes
* Immunology/
109
hHow are microorgasms usedto make yoghurt?
Yoghurt is milk that has undergone **fermentation** by bacteria. The bacteria converts **lactose to lactic acid**. The **acidity** denatures the milk protein, causing it to **coagulate**. The bacteria partically digests the milk, making it easier to digest.
110
What bacteria is used to make yoghurt?
* *Lactobacillus bulgaricus*
* *Streptococcus thermophilus*
111
What causes the milk to coagulate when producing yoghurt?
The increase in acidity as lactic acid is built up denatures the milk protein causing milk to coagulate.
112
What bacteria can be added to yoghurt as probiotics?
* *L. acidophilus*
* *L. subsp. casei*
* *Bifidobacterium*
113
What are probiotics?
Bacteria which may benefit human health by improving the digestion of lactose, **aiding gastointestinal function and stimulating the immune system**.
114
What bacterium can milk be treated with to ptoduce lactic acid from lactose?
*Lactobacillus*
115
How is cheese produced?
Milk is pre-treated with **Lactobacillus**, producing** lactic acid** from lactose. Once acidfied, the milk is mixed with **rennet**- containing the enzyme **rennin** (chymosin). Rennin **coagulates** the milk protein (**casein**) in the presence of calcium ions. This results in a solid, called **curd**, which is separated from theliquid (**whey**). The bacteria continues tro grow, producing more lactic acid. The curd is then pressed into moulds.
116
What produces the flavours charateristic of the yogurt?
Its fermentation.
117
Once acidified, what is added to milk to produce cheese? What effect does this have?
Rennet- it contains the enzyme rennin which coagulates the milk protein (casein) in the presence of calcium ions.
118
What is the name of the milk protein the is coagulated during the production of cheese?
Casein.
119
What happens to casein in the presence of calcium ions during the production of cheese?
* Kappa-casein, which keeps the casein in solution, is broken down. This makes the casein insoluble.
* The casin is precipitated bu the action of calcium ions, which bind molecules together.
120
What determines the characteristic of cheese?
Treatment while making the pressing the curd determines the characteristic.
121
How is curd separated from the whey during the production of cheese?
By cutting, stirring and heating.
122
What is the flavour of cheese dtermined by?
Flavour is determined during the **ripening and maturing** process.
More flavour can be added by **inoculation with fungi** such as penicillium and produce blue cheese.
123
Where is renet from?
The stomachs of young mammals. Howeve, it can niow be produced by genetically modified bacteria.
124
What microorganism is involved in making bread?
Yeast (*Saccharomyces cerevisiae*)
125
What are the 3 main steps of producing bread?
1. **Mixing**- ingedients are mixed by kneading. The **produces** the dough.
2. **Proving/ fermenting**- dough is left in a warm place for up to 3 hours while yeast **respires anaerobically**, producing **carbon dioxide bubbles**, causing the dough to rise.
3. Cooking- Any **alcohol evaporates** during the cooking process.
126
What is bread a mixture of?
Flour, water and salt with some yeast.
127
How are alcoholic drinks made?
They are a product of anaerobic repiration of yeast.
128
How is wine produced?
Make using grapes that have naturally have yeast on their skin. Grapes conatin fructose and glucose- when the grapes are crushed, the yeast uses these sugars to produce carbon dioxide and alcohol.
129
How is ale or beer produced?
It is brewed using **barley grains** that are beginning to **germinate**. This process is called **malting**. As the grain germinates it convertes **stored starch to maltose**, which is repired by the **yeast**. **Anaerobic respiration** produces **cardon dioxide and alcohol**. **Hops** are used to give a bitter taste to the liquid.
130
What miroorganism is used to manufacture prtoein used directly as food?
*Fusarium venenatum* (fungus)
131
What is Quorn a good example of?
It s a good example of a mycoprotein.
132
What is a mycoprotein?
The fungal protein or mycoprotein is know as a single-cell protein (SCP).
133
What microorganisms are used to produced single-cell protein (SCP)?
* *Kluyveromcyes*
* *Scytalidium*
* *Candida*
134
Why are microorganisms useed to produce SCP?
The fungi can produce protein with a similiar amino acid profile to animal and plant protein.
They also can grow on amolst any organic substrate, including waste.
135
What are the advantages of using microorganismis in biotechnology to make food?
* Productionn of protein is faster than that of animal or animal.
* Biomass has very high protein content.
* No aminal welfare issues.
* Contains no animal aft or cholesterol.
* SCP can be combines with the removal of waste prosucts.
136
What are the disadvantes or using microoganisms in biotechnology to produce food?
* Some people may not want to eat fungal protein or food grown on waste.
* Protein needs to be purified to ensure it is uncontaminated.
* Amino acid prfoile may be different from traditional animal protein- can be deffienct in methionine.
* SCP does not the the same taste or texture.
* Conditions are ideal to grow other microorganisms, so sare must be taken that the culture isnt infected.
137
Where does the production of commercial drug production use?
Fermenters.
138
Why are fermenters used in commercial drug production?
The growing condtions can be used to ensure the best possible yeild of the product.
139
In a fermenter, what conditions can be controlled?
* Temperature
* Nutrient available
* oxygen availability
* pH
* Concentration of product
140
Why can temperature be controlled in a fermenter?
Too hot and enzymes will denature, too cool and growth could be limited.
141
Why can the nutreints available in a fermenter be controlled?
Microorganisnms **require nutreits to grow and synthesis the product**. Sources of carbon, nitrogen, minerals and vitamins are needed.
142
Why can the oxygen availability be controlled in a fermenter?
Most organisms respire aerobically.
143
Why can the pH in a fermenter be controlled?
Enzyme activity and hense growth and synthesis are affected by extemes of pH.
144
Why can the concenration of the product be controlled in a fermenter?
If the product is allowed to build up, it may affect the synthesis process.
145
How is a fermenter set up?
A fermenter must be **steralised** used superheated steam. It can then be **filled with all the components** required for growth and supplied with a **starter culture** of the microogranism to be used. The culture will be **left to grow and synthesis** the products.
146
What must be done before components can be put into a fermenter?
The fermenter must be steralised with superheated steam.
147
What products are synthesised by microorganisms during normal metobolism when they are actively growing?
Primary metabolites.
148
What are primary metabolites?
Products are **continually** released from the cells and can be **extracted continously from the fermenting broth**.
149
Due the primary metabolites being continually released, what must be done to he broth?
Some of the broth is removed regularly to ectract the product and remove cells from the broth- otherwise the population would become too dense.
150
What is continous culture?
Organisms grow at a specific growth rate- primary metabolites as they are continously released.
151
What products are produced in a fermenter when the cells are placed under stress?
Secondary metabolites.
152
When are the secondary metabolites mostly produced?
During the stationary phase of growth.
153
How are secondary metabolites made?
The culture is set up with a **limited quantity of nutrients** and allowed to ferment for a **specific time**. After this time, the fermenter is emptied and the product can be extracted from the culture. This is known as **batch culture**.
154
What sort of cultur does the secondary metabolites produce?
Batch culture.
155
What is a batch culture?
To extract the products, the fermenter must be emptied so the product can be extracted from the culture.
156
What is asepsis?
Asepsis is ensureing that sterile conditions are maintained.
157
What term means ensureing that sterile conditions are maintained?
Asepsis.
158
Why is asepsisimportant for processes involving biotechnology?
The nutreint medium would also support te growth of unwanted microorganisms.
159
Why does the presence of unwanted microorganisms reduce the production of wanted products?
* Compete with the cultured microorganisms for nutreints and space.
* Reduce thye yeild of useful products.
* Spoil the product
* Produce toxic chemicals
* Destroy the cultured microoragisms and their products.
160
What must be done in the process of food and medicinal chemicals being produces if the presence of unwanted microorgaims is detected?
All products must be discarded if contamination by unwanted orhanisms occur.
161
What is used for the mass production of penicillin?
The fungus ***Penicillium chrysogenum*** is fermented.
**Modern strains** of the fungus have been **selectively bred** to be **more productive** than the early strains.
162
What sort of product is penicillin?
Penicillin is a secondary metabolite.
163
Describe the fermentation of penicillin.
Penicillin is a **secondary metabolite**- it is only produced once the **population** has reached a **certain size**. Therefore, penecillin is manufactured by **batch culture**.
164
Describe the process of producing penicillin.
1. The **fermenter** is run for **6 to 8 days**. The culture is then **often filtered** to remove the cells.
2. The antibiotic is **precipitated** as crystals by the **addition of the potassium compounds**. The antibiotic may be **modified** by the action of **other micoorganisms or by chemical needs**.
3. The antibiotic is **mixed with inert substances** and prepared for the **administeration** in tablet form, as syrup or in a form for injection.
165
How was synthetic human insulin developed?
Synthetic human insulin was developed by genetically modifying a bacterium.
166
By what method is insulin produced by?
Continous culture.
167
How is synthetic human insulin produced?
The gene for human insulin was **combined with a plasmid** to act as a **vector**, so the gene can be inserted into the bacteria ***Escherichia coli***. The resulting genetically modified bacterium enabled the production of **vast quantities** of human insulin at relativley **low cost**.
168
What is bioremediation?
Bioremediation is the use of microorganisms to clean the soil and underground water on poluted sites.
169
What term is used to describe the use of microorganisms to clean the soil and underground on polluted sites?
Bioremediation.
170
During bioremediation What do the microorganisms do?
The organisms convert the toxic pollutants to less harmful substances.
171
Where did the idea of bioremediation start?
The idea started with a modified bacterium enabaled it to break down crude oil.
172
What can be treated wth bioremediation?
Oil spills, solvents and pesticies.
173
What does bioremediation involve?
It involves stimulating the growth of suitable microbes that use the contaminants a source of food.
174
What conditions does bioremediation require?
It requires the growth of microogranisms which are:
* Available water
* A suitable temperature
* Suitable pH
175
Where conditions are not suitable for microorganisms what can be modified to change this?
They may be modified by the addition of **suitabe substances**. In some cases, **addiational nutreints**, such as mollases, may be needed to ensure the microogransims can grow effectively. It may also be needed to **pump oxygen** in for aerobic bacteria.
176
If modifications cannot be made so that conditions are suitable for microogansims for bioremediation, what can be done?
Where conditions cannot be made *in situ*, the soil may be dug up and moved to be treated *ex situ*.
177
What are the aadvantages of bioremediation?
* Uses natural systems.
* Less labour/ equiptemnt is required.
* Treatment *in situ*.
* Few waste products.
* Less risk of exposure to clean-up personnel.
178
What products cannot be treated by bioremedation?
Bioremediation cannot be used to treat **heavy metals** such as **cadmium and lead**.
179
What is agar?
A **polysaccharide of galactose** obtained from **seaweed**, which is used to thinken the medium into gel.
180
What is aseptic technique?
**Sterile techniques** used in **culturing** and **manipulating** microoranisms.
181
In a laboratory, what are the 2 types of growth mediums microorganisms are grown in?
* A soup-like liquid called **broth**, kept in bottles or tubes.
* A set jelly-like sunstance called **agar**, which is melted and poured into Petri dishes.
182
What does nutrient agar contain?
It contains:
* Peptones (from the enzymatic breakdown of gelatine)
* Yeast extrect
* Salts
* Water
* May contain glucose or blood
183
Why has aseptic techniques been developeed?
They have been developed to reduce the likelihood of contaminating the medium with unwanted bacteria or fungi.
184
What is the standard procedure of aseptic techniques?
1. Wash your **hands**.
2. Disinfect working **area**.
3. Have bunsen burner operating nearby to heat the **air**.
4. As you open a **vessel**, pass the neck of the bottle over the flame to prevent bacteria in the air entering the bottle. Flame the bottle as its closed.
5. Do not lift the **lid of the Petri dish** completley off- only enough to allow introduction of the required miroorganisms.
6. Any **glassware or metal equipemnt should** be passed through the flame before and after contect with desired microoganisms.
185
Why is having a bunsen burner opeating nearby to heat the air an aseptic technique?
It causes the air to rise and prevents air-borne micoorganisms settling. It also creates an area around it of sterile air in which microbiologists can work.
186
What are the main steps involved in growing microorganisms on agar plates?
* Sterilisation
* Inoculation
* Incubation
187
What is the 1st steps invovled in growing a microorganism on a agar plate?
Sterilisation- The nutreint agar medium and equipment to be used must be sterilsed.
188
Before growing microorangisms, how is the agar medium sterilised?
The medium is heated in an **autoclave** at 121°C for 15mins. The kills all living organisms including any bacterial or fungal spores. Whehn the medium has celed enough to handel, it is poured into a sterile Perti dish and left to set. It is important that the lid is kept on to prevent infection.
189
What is agar medium heated in to steralise it?
An autoclave.
190
In an autoclave, how is the high temperatures achieved to steralise the agar medium?
The high temperatures are achieved by **boiling water** under **high pressures** inside the autoclave.
191
What is the second step of growing microorganisms on agar plates?
Inoculation- the introduction of microorganisms to the sterile medium.
192
What are the 4 ways inoculation of a microorganism can be achieved?
* Streaking
* Seeding
* Speading
* Moist cotton bud
193
How is streaking a way of inoculation?
A **wire inoculating loop** is used to **transfer a drop of liquid medium** onto the surface of the agar. The **drop is drawn out** into a streak by **dragging the loop across** the surface. Take care not to brak the surface of the agar.
194
How is seeding a way of inoculation?
A sterile pipette can be used to transfer a small drop of liquid medium to the surface of the agar or to the Petri dish before the agar is poured in.
195
How is spreading a way of inoculation?
A sterile **glass spreader** may be used to **spread the inoculated drop** over the surface of the agar.
196
How can a moist cotton bud be used for inoculation?
A small cotton swab or cotton bud can be mosisened with distilled water and used to collect microorganisms from a surface and then carfully wiped over the surface of the agar medium.
197
What is the 3rd step of growing a microoganism on an agar plate?
Incubation
198
What is done in the incubation step on growing microoganisms on an agar plate?
The Petri dish is labelled and the top taped to the bottom. The Petri dish is then placed in a suitable warm anviroment such as an incubator, it should be placed upside down. Cultures can be examined 24-36 hours later.
199
How many strips of tape are used to seal the top if a Petri dish to the bottom?
2 strips.
200
Why is only 2 pieces of tape used to attatch the top of a Petri dish to the bottom?
It ensures the pertri dish is not sealed completly as this can lead to selection of anaerobic bacteria which may be pathogenic.
201
Why should a Petri dish be placed upside down in an incubator?
It should be upside down as this prevents drops of condensation falling onto the surface of the agr. It also prevents the agar medium from drying out too quickly.
202
What may be observed when examining cultures on a Perti dish?
Bacteria grow into visable colonies which may be shinyy or dull. Some colonies are with rounf edges, while others can have crenated adges. The colonies can be different colours. Each colony results from a single bacterium.
203
What must you make sure to do when examining the cultures on a Perti dish?
Do not open the Petri dish.
204
How may fungi growing on a Perti dish be observed?
**Filamentous fungi** grow into a **mass of hyphae**, which may be circular, but the mass is not shiny and ften looks like cotton wool with fluffy aerial hyphae. **Single-celled fungi** (yeasts) grow as **circular colonies**.
205
What must be done after examining cultures on a Petri dish?
All Petri dishes must be **completely steralised after use and before disposal**. Throughly **wash your hands** after handeling the perti dish, as any moisture coming out of the dish coud be a **source of infection**.
206
What can be observered when bacteria have grown in a liquid medium?
A liquid broth is initially clear but will turn cloudy when bacteria have grown.
207
What can a liquid broth be useful for when growing microorganisms?
It can be useful for increasing the numbers of microoganisms before transfering to agar plates for counting or identification.
208
What can a liquid broth be used to investigate?
Used to investigater population growth.
209
What can agar plates be sued to investigate?
Counting or idengtification of microorganisms.
210
What is a closed culture?
A culture which has **no exchange of nutrients or gases** with the external enviroment.
211
What is serial dilation?
A sequence of dilutions used to reduce the cencentration of a solution susension.
212
How can you measure the growth rate of microorganism population in a liquid broth?
A sterile broth is inoculated and the population size measured at regular intervals during incubating. The population size can be measured by transffereing a small samle to an agar plate and incubating the agar culture- each individual microoganism will produce a visable colony.
