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Artificial Vegetative propagation has two main methods
­ Taking cuttings, section cut between nodes and treated with root growth hormones to encourage root growth
­ Grafting ­ shoot section of woody plants (fruit tree) joined to already growing root/stem (rootstock)
­ The graft grows as a clone whilst the rootstock isn't genetically identical
· Artificial propagation using tissue cultures (a more modern approach)
­ Tissue cultures can help to generate large stocks of a valuable plant, these stocks are also guaranteed disease free
· Micropropagation by callus tissue culture
­ Small piece of tissue taken from plant to be cloned, usually from shoot tip, this is the EXPLANT
­ This is grown on a nutrient growth medium
­ Cells in tissue divide, but do not differentiate, form mass of cells called CALLUS
­ After few weeks, single callus cells removed and put on a growth hormone medium to encourage shoot growth
­ Again, after a few further weeks, the growing shoots are placed on a medium that encourages root growth
­ The growing plants are then transferred to a greenhouse to be acclimatised and grown further before being
planted outside
· Advantages
­ Farmers know what crop they are growing in terms of taste, yield and resistance
­ Farmers costs are lowered as all the crop can be harvested at the same time
e s
­ This is a `refinement' of selective breeding
lo n
­ Micropropagation is also much faster than selective breeding
C
l ltu r e
· Disadvantages
ic i a u
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All plants equally susceptible to disease and pests, eg Potato Famine
Same as natural cloning
r t f
i gr i c
A dA
an…read more

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Artificial Cloning in animals ­ two possibilities
Splitting embryos ­ `artificial identical twins'
Cloning
­
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Cells from developing embryo can be seperated out
Each one can go on to produce a separate, genetically identical organism Animals
­ Used to clone cows, sheep, rabbits and toads, as well as a primate in 2000
· Nuclear Transfer
­ Differentiated cell from an animal is taken
­ Nucleus placed in egg cell which has had it's nucleus removed (enucleated)
­ The egg then develops using genetic information from the inserted nucleus
­ Dolly ­ 1996 ­ cell taken from mammory gland of female sheep, nucleus transplanted into enucleated cell from
second sheep, this was planted into uterus of a third sheep before being placed in a fourth to develop
· Advantages of cloning animals
­ High-value animals can be cloned in large numbers
­ Rare animals can be cloned, preserving the species
­ GM animals that have pharmaceutical chemicals in their milk can be produced quickly
· Disadvantages
­ Some High-value animals do not live in brilliant welfare
­ Genetic uniformity may cause them to not be able to cope well with change
­ Still unclear whether animals from nuclear transfer will remain healthy in the long term
· What is non-reproductive cloning
­ Cloning to generate cells, tissues and organs to replace those damaged by accident or disease
­ Advantages include
­ Less likely to be rejected as they are genetically identical, less pressure on a waiting list for organ transplant
­ Often referred to as therapeutic cloning but many people object to it's use within humas…read more

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Biotechnology ­ industrial use of living organisms to produce food, drugs and other products
· Ancient biotechnology includes yogurt making and brewing
· Modern biotechnology is recombinant DNA techology, with four major applications
1. Healthcare and medical processes 2. Agriculture
3. Industry 4. Food Science
· Use of microorganisms in biotechnology
­ Favourable because microorganisms:
­ Grow rapidly in favourable conditions, double numbers in up to 30 minutes
­ Often produce proteins that can be harvested
­ Can be genetically engineered to produce specific products
­ Grow well at relatively low temperatures
­ Not dependant on climate, thus can be grown worldwide
­ Tend to generate pure products
Purpose Example Organisms involved
Food Cheese Bacterial growth in milk changes taste and texture, whilst preventing other
making bacteria from growing thus acting as a preservative
production
Drug Penicillin Fungus grown in culture produces antibiotic as a by-product of it's
(antibiotic) metabolism
production
Enzyme Calcium Fungus produces citric acid as a by-product of metabolism
production citrate
Bioremediation Waste water Variety of bacteria and fungi use organic waste in the water as nutrients and
treatment make the waste harmless
of waste…read more

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The growth curve
· The standard growth curve in a `closed system'
­ Lag phase- Organisms are adjusting to the surroundings, population fairly constant
­ Log phase- population increases exponentially, Every individual has plentiful space and resources
­ Stationary phase ­ Nutrient levels decrease, waste products build up, organism death= organism production
­ Death phase ­ Nutrient exhaustion, toxic levels of waste product, eventually all organisms in the system die
· Fermentation and Fermenters
­ Culturing of microorganisms in fermentation tanks, both aerobically and anaerobically
­ Substances generated by growth of microorganism, separation and purification to obtain the final product
· Metabolism is a process, metabolites are the products
­ Metabolism = sum total of all chemical reactions that occur within an organism
­ Including: new cells and cellular components; chemicals such as hormones; waste products
­ A waste product of one organism's metabolic processes are the vital nutrients required by other organisms
· Primary and secondary metabolites
­ Primary metabolites - substances produced by an organism as part of it's normal growth, including amino acids,
proteins, ethanol and lactate
­ Production of primary metabolites matches growth of the population of the organism
­ Secondary metabolites ­ substances produced but not part of an organisms normal growth, includes antibiotic
chemicals
­ Production usually starts after main growth period and does not match population growth of an organism
­ Only a relatively small number of microorganisms produce secondary metabolites…read more

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Commercial applications of biotechnology
· Industrial-scale fermenters and `scaling up'
­ Commercial applications usually require growth of a particular microorganism on an enormous scale
­ An industrial-scale fermenter is a he tank with tens of thousands litres capacity
­ Growing can be manipulated and controlled to ensure a good yield
­ Precise conditions depend on the microorganism being cultured and if its primary/secondary metabolite needed
­ Factors include temperature, type and time of addition of nutrient, oxygen concentration and pH
­ Large cultures need `starter' populations, which are initially grown in a sterile nutrient broth
· Batch and continuous culture
­ Batch culture ­ microorganism starter population mixed with specific quantity of nutrient solution
­ Then it is allowed to grow for a fixed amount of time with no additional nutrients
­ At the end of this period the product is removed and fermentation tank is emptied
­ Penicillin is produced like this
­ Continuous culture ­ nutrients added and products removed at regular intervals or continuously
­ Human hormones, such as insulin are produced like this, from genetically modified E.coli
· Asepsis is vital in biotechnological processes involving microorganisms
­ Nutrient medium that culture is grown in could also support life of many unwanted microorganisms
­ Any unwanted microorganism is called a contaminant
­ Unwanted organisms: compete for nutrients and space, reduce yield of useful products, may cause spoilage etc
­ In processes where foods or medicinal chemicals are being produced, contamination renders all product unsafe
­ Aseptic techniques refer to measures taken to ensure asepsis (the absence of unwanted microorganisms)…read more

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