Cloning and Biotechnology Flashcards
Define clone
Offspring which is genetically identical to the parent organism
Define asexual reproduction
The generation of new individuals by mitosis to produce clones
Define vegetative propagation
The production of plant clones from non-reproductive tissues
Give 4 ways plants naturally clone
- Bulbs
- Runners
- Rhizomes
- Stem tubes
What is ‘taking a cutting’?
Removing and planting short sections of stem of a plant in order to produce clones of that plant
How can the success of cuttings be improved?
- Use hormone rooting powder
- Reduce the number of leaves
- Cover with a plastic bag for a few days
- Make an oblique cut in the stem
Give 2 advantages of taking cuttings over seeds
- less time is needed to grow an adult plant
- gurantees quality of plants as their characteristics are known
Give a disadvantage of taking cuttings over using seeds
-lack of genetic variation in offspring
What is micropropagation?
The process of producing large numbers of genetically identical offspring from a single plant using tissue culture
Why might micropropagation be used to clone a plant?
If a plant:
- does not readily produce seeds
- does not respond well to natural cloning
- is very rare
- has been genetically modified with difficulty
Where must tissue be taken from in the tissue culture of plants?
From the shoot tips or buds
What type of tissue must be used to micropropagate a plant?
Meristematic
Define explant
The material removed from the plant which is being cloned
Outline the steps in micropropagation of a plant
- Take some tissue from the shoots or roots of a plant
- Sterilised the sample (using bleach or ethanol)
- Place the explant in sterile culture medium containing plant hormones which stimulate mitosis
- Mass of cells (callus) is divided and put into new culture medium which stimulates plantlet growth
- Plantlets are potted into compost
Why must micropropagation be done under sterile conditions?
In order to prevent the plant tissue from becoming contaminated with bacteria or fungi
Give 4 advantages of micropropagation
- allows for rapid production of large numbers of plants
- provides a reliable way to increase numbers of rare/endangered plants
- plants can be produced at any time of year
- GM plants can be produced in large numbers
Give 4 disadvantages of micropropagation
- produces a monoculture
- expensive and requires skilled workers
- if source material is infected with a disease, all clones will be
- explants and plantlets are vulnerable to infection
What is a callus?
A mass of undifferentiated cells
Give 3 examples of plants grown by micropropogation
- potatoes
- sugar cane
- bananas
Give an example of a plant grown by taking cuttings
Sugar Cane
Give an example of natural cloning in vertebrates
Monozygotic twins
Give 2 ways in which animals can be artificially clones
- Artificial twinning
- Somatic cell nuclear transfer
Outline the steps in artificial twinning
- Animal with desirable trait is treated with hormones so she produces more mature ova than usual
- Mature eggs are removed and fertilised by semen in the lab
- When totipotent, the embryonic cells are split to produce several small embryos
- Embryos are then implanted into the womb of surrogate mothers
Why is artificial twinning carried out?
- Greatly increases the number of offspring produced by animals with best genes
- embryos can be frozen and the success of the animals can be assessed before all embryos are brought to term
Outline the process of somatic cell nuclear transfer
- A nucleus is removed from a somatic cell of an animal
- A nucleus is removed from an egg cell of a different animal, the somatic cell nucleus is then placed in the enucleated egg cell
- A mild electric shock fuses the cell and nucleus and they begin dividing
- Embryo is transferred into a surrogate
Give 4 advantages of somatic cell nuclear transfer
- enables GM embryos to be replicated
- useful for pharming
- enables scientists to clone specific animals
- enables rare, endangered, or extinct animals to be reproduced
Give a disadvantage of somatic cell nuclear transfer
It is a very inefficient process, many eggs are used to produce a single clone
Give 3 advantages of animal cloning
- Desirable genetic characteristics are always passed on
- Infertile animals can be reproduced
- Can be used to increase the population of an endangered species, helping to preserve biodiversity
Give 2 disadvantages of animal cloning
- many cloned animal embryos fail to develop
- animals produced by cloning have shortened lifespans
What is pharming?
When animals are geneticially modified to produce pharmaceuticals e.g. human proteins produced in milk
What is theraputic cloning?
A form of somatic cell nuclear transfer which has the potential to grow replacement organs which will not trigger an immune response
What is biotechnology?
The exploitation of biological processes for use in industrial processes
Give 4 reasons why microorganisms are useful for biotechnology
- No welfare issues to consider
- Can be easily genetically modified
- Rapid growth rate
- Conditions for growing and nutrient requirements are relatively cheap
What is indirect food production?
When products made by microorganisms are used to make food (i.e. the microorganisms themselves are not eaten)
Give 4 examples of indirect food production by microorganisms
- Brewing beer
- Baking bread
- Cheese making
- Yogurt making
What is direct food production?
The microorganism itself is eaten as food
Give an example of direct food production
Quorn is made from a single celled fungus
Give 5 advantages of using microorganisms to make food
- Microorganisms can be grown quickly,easily, and cheaply
- Microorganisms can be grown on unwanted/wast food
- Products are easy to separate/pure
- Microorganisms can produce products (such as protein) very quickly
- Microorganisms can be grown at low temperatures
Give 4 disadvantages of using microorganisms to make food
- if conditions are sub-optimal some microorganisms produce toxins
- downstream processing of products is required
- Sterile growing conditions are needed which increases cost
- People dislike the thought of eating microorganisms
Define bioremediation
The use of microorganisms to break down polluntants and contaminants in soil or water
How can genetic modification be used in bioremediation?
Scientists are trying to genetically modify bacteria so they can break down contaminants they would not usually encounter e.g. scientists have modified a bacterium to remove mercury from water
Which 2 ways can microorganisms be grown in a lab?
Microorganisms can be grown by:
- innoculating broth or
- innculating agar
Outline how to inoculate a nutrient broth
- suspension of bacteria is made
- known volume is mixed with a sterile nutrient broth
- flask is stoppered to prevent contamination from air
- Incubate at a suitable temperature, shaking regularly
Outline how to inoculate agar
- inoculating loop is sterilised by heating in a flame
- loop is dipped in bacterial suspension
- zig-zag streaks are made across the agar, taking care to keep the agar surface intact
What are aseptic techniques?
Techniques used to culture microorganisms in sterile conditions so they are not contaminated with unwanted microorganisms
Which stage of the standard growth curve does the red line represent?
Lag phase
What is the lag phase of the standard growth curve?
- Microorganisms are adapting to their new environment
- They are growing by synthesising enzymes takes time
- Not yet growing at their maximum rate
Which stage of the standard growth curve does the green line represent?
Log/exponential phase
Which stage of the standard growth curve does the purple line represent?
Stationary phase
Which stage of the standard growth curve does the blue line represent?
Death/decline phase
What happens in the log/exponential phase of the standard growth curve?
- Rate of bacterial reproduction is close to or at it’s theoretical maximum
- sufficient space and nutrients for population, so little competition between individuals
What happens in the stationary phase of the standard growth curve?
- Net growth in population is 0
- Death rate=rate of cell division
- Nutrient levels decrease and waste products build up
What happens in the death/decline phase in the standard growth curve?
- Reproduction has almost ceased
- Death rate of cells is increasing
- Food is scarce and waste products are at toxic levels
Give 5 factors which limit bacterial growth
- Nutrients avaliable
- Oxygen levels
- Temperature
- Build-up of waste products
- Change in pH
What is batch fermentation?
The Microorganisms and nutrients are placed in the bioreactor and not removed until fermentation is complete
What is continuous fermentation?
When the microorganism is placed in the bioreactor and nutrient medium is added continually whilst culture broth is removed.
What kind of metabolite is harvested from a batch culture?
Secondary metabolite
What kind of metabolite is harvested from a continuous culture?
Primary metabolite
At what stage in the standard growth model are products harvested from in batch culture?
Stationary phase
At what stage in the standard growth model are products harvested from in continuous culture?
Exponential/log phase
Give 2 advantages of batch culture over continuous culture
- The risk of contamination is low
- Aseptic conditions are easier to maintain as the bioreactor is sterilised when it has been emptied
Give an advantage of continuous culture over batch culture
The process is more efficient as product is continuously produced
What is a primary metabolite?
A substance formed as part of normal growth
What is a secondary metabolite?
A substance not produced as part of normal growth i.e a substance produced when an organism is experiencing stress
Does the production of primary metabolites follow the standard growth curve?
Yes
Does the production of secondary metabolites follow the standard growth curve?
No, production begins in stationary phase
What is downstream processing?
The recovery and purification of biosynthetic products, including the recycling of salvageable components and proper treatment and disposal of waste
How do bioreactors maintain ideal growing conditions?
- Cooling jacket prevents bioreactor getting too hot
- Contains pH, temperature, and Oxygen probes
- Mixing blades ensure good oxygenation of the nutrients
- Air entering the bioreactor is sterilised
Why are isolate enzymes better than using whole organisms?
- less wasteful
- more efficient
- more specific
- less downstream processinf required
Why are extracellular enzymes used more than intracellular enzymes in biotechnology?
- extracellular enzymes are easier to isolate
- fewer extracellular enzymes are produced so it is easier to isolate them
- extracellular enzymes are more robust
What are immobilised enzymes?
Enzymes which are attached to an inert support system over which the substrate can pass and be converted to product
Give 4 advantages of using immobilised enzymes
- enzymes are resuable so reduces cost
- can be easily separated from products, making downstream processing easier
- Purer product can be formed
- enzyme stability increased so can work at a higher temperature, increases rate of reaction
- Enzyme works in changed pH
Give 3 disadvantages of using immobilised enzymes
- reduces the efficiency of the enzymes
- higher initial cost
- requires more complex reactors
What are the 4 methods of immobilisation?
- Ionically bond to solid support e.g. ceramic beads
- Covalent bond to substances e.g. other enzymes, collagen
- Entrapment e.g. in gel based polysaccharides or cellulose
- Membrane separation
Give 3 advantages of membrane entrapment of immobilised enzymes
- Relatively small effect on enzyme activity
- Relatively simple to do
- Widely applicable to different processes
Give a disadvantage of membrane entrapment of immobilised enzymes
- diffusion of substrate to and product from active site can be slow
Give an advantage of entrapment of immobilised enzymes
Widely applicable to different processes
Give 2 disadvantages of entrapment of immobilised enzymes
- May be difficult to entrap
- diffusion of substrate to and product from active site can be slow
Give 2 advantages of covalent/ionic bonding to inorganic carriers for immobilised enzymes
- enzymes very accessible to substrate
- enzymes strongly bonded so unlikely to be lost
Give an advantage of covalent/ionic bonding to inorganic carriers for immobilised enzymes
Active site of enzyme may be modified in the process, making it less effective
Give 2 advantages of adsorption to inorganic carriers for immoblised enzymes
- can be used for many different processes
- enzymes are easily accessible
Give a disadvantage of adsorption to inorganic carriers for immoblised enzymes
Enzymes can be lost from the matrix relatively easily
What is the funciton of glucose isomerase?
Converts fructose to glucose
What is the function of penicillin acylase?
Makes semi-synthetic penicillins
Give 3 examples of use of immobilised enzymes in biotechnology
- Penicillin acylase
- Glucose isomerase
- Lactase
