Cloning and biotechnology Flashcards
1
Q
What are some examples of natural cloning (vegetative propagation)?
A
- Bulbs, runners, rhizomes (underground), tubers
2
Q
Describe the process of micropropagation?
A
- Take a small sample of (meristem) tissue.
- Sterilise the sample, dip in bleach.
- Explant placed in a sterile culture medium containing auxins and cytokinins which stimulate mitosis.
- Cells proliferate, forming callus.
- The callus is divided up, put into multiple new culture mediums containing a different mixture of hormones and nutrients.
- Many genetically identical plantlets produced which can be potted in compost.
- Can be made in to a crop.
3
Q
What are the advantages of micropropagation?
A
- rapid
- large number of plants produced
- disease-free
- can be done to GMOs, seedless, and rare plants.
4
Q
What are the disadvantages of micropropagation?
A
- Produces a monoculture - susceptible to same diseases etc
- Expensive and skilled
- Vulnerable to infection when explants/plantlets
- If infected by virus, all clones will be too
- Many can be lost in the process
5
Q
How can natural cloning occur in invertebrates?
A
- Starfish can regenerate entire organisms from fragments.
- Budding of hydra
- Parthenogenesis
6
Q
How can natural cloning occur in invertebrates?
A
Monozygotic twins.
7
Q
Describe the process of artificial twinning.
A
- A cow with desired traits is selected, and given hormones so she superovulates.
- Her ova are fertilised by AI or naturally, and the early embryos are flushed out of her uterus.
- Alternatively they can be fertilised by IVF with high-quality bull semen.
- While the cells are still totipotent, the embryo is split into several smaller embryos.
- These are lab grown briefly, then each one is implanted into a different surrogate where they develop into foetuses.
8
Q
How does the process differ in pigs?
A
- Multiple embryos implanted in one surrogate as pigs normally have litters, a single embryo would be reabsorbed.
9
Q
Describe the process of somatic cell nuclear transfer.
A
- Remove nucleus from a somatic cell of an adult animal.
- Enucleate an ovum from another animal of the same species.
- Nucleus is placed into enculeated ovum and given mild electric shock so it fuses and begins to divide.
- In some cases the nucleus from the adult cell is not removed, and the the two cells undergo electrofusion and begin to divide.
- The embryo that develops is transferred into the uterus of a third animals, where it develops to term.
- The new animals is a clone of the somatic cell donor, but has egg cell’s mitochondrial DNA.
10
Q
What are the potential downsides for the cloned animals?
A
- May be prematurely aged due to inheriting DNA with shortened telomeres.
11
Q
What are arguments for animal cloning?
A
For: - more offspring than usual.
- Specific animals can be replaced using SCNT e.g race horses.
- Endangered species.
12
Q
What is biotechnology?
A
- Involves applying biological organims or enzymes to the synthesis, breakdown, or transformation of materials for human use.
13
Q
Why are microorganims ideal for biotechnology?
A
- No welfare issues.
- Can be grown quickly and in large numbers.
- Huge range of different types.
- G.E allows for artifical manipulation of them.
- Simple and cheap requirements.
14
Q
How is bread produced using biotechnology?
A
- Yeast is mixed with sugar and water to respire anaerobically.
- Creates CO2 bubbles which aid rising.
15
Q
How is beer/wine produced using biotechnology?
A
- Yeast respires anaerobically to produce ethanol. can be GM to ferment at lower temps.
- Digest fruit sugars and produce ethanol and CO2.
16
Q
How is cheese produced using biotechnology?
A
- Bacteria feed on lactose in milk.
- Bacterial cultures separate curds and wheys.
- Curds left to mature with bacteria.
17
Q
How is yoghurt produced using biotechnology?
A
- Milk incubated with bacteria (often Lactobacillus bulgaricus and Streptococcus thermophilus) produce polymers which give yoghurt its flavour and texture.
18
Q
What are the alternative methods of counting viable bacteria population? (other than serial dilution)
A
- Turbidity: using a colorimeter to compare to create a calibration curve of bacterial population vs absorption/transmission.
- Haemocytometer: special slide with indent, count number of bacteria in the 0.1mm^3 indent and scale.
19
Q
Why can alternative methods of counting bacteria populations result in overestimates?
A
- Dead bacteria can be counted.
20
Q
What are secondary metabolites?
A
- Substances not necessary for normal cell growth, but produced in some specific conditions.
21
Q
What foods are made by indirect food production using microorganisms?
A
- Cheese, milk, yoghurt, bread.
- Microorganism action on other food.
22
Q
What foods are made by direct food production using microorganisms?
A
- Quorn, fusarium fungus
23
Q
What are the advantages of the speed of using microorganisms to produce human foods?
A
- Fast reproduction and faster protein production than plants or animals.
- not dependent on breeding cycles, weather; supply can be increased/decreased with demand.
24
Q
What are the health and flavour benefits of using MOs to produce human food?
A
- high protein and little fat
- can be genetically modified to produce desired proteins
- can be made to taste like anything
25
What are the cost benefits of using MOs to produce human food?
- can use a variety of waste materials to grow, reducing costs
- Low temps
26
What are the ethical considerations of using MOs to produce food for humans?
- No welfare or religious issues.
- Some people object to eating GM food.
27
What are the safety/purity concerns with using MOs for human food production?
- Can produce toxins under certain conditions
28
What are the arguments against animal cloning?
A: - SCNT is very inefficient, many eggs to produce a single cloned offspring.
- Many cloned animal embryos fail to develop and miscarry/are born deformed.
- inherit aged DNA
29
What additional processes are required to use MOs for human food production?
- MOs must be separated from nutrient broth and product must be purified and processed
- Sterile conditions required
30
What is bioremediation?
When MOs are used to break down pollutants and contaminants in the soil or in water.
31
What are the two forms of bioremediation?
- natural vs GM organisms
32
How can natural organisms be used for bioremediation?
- Some organisms are already capable of breaking down organic material into water and CO2.
- E.g oil and sewage can be bioremediated with natural organisms.
33
How can GM organisms be used for bioremediation?
- Scientists are trying to develop GM bacteria which can break down or accumulate substances they would not naturally encounter.
34
what are the stages of bacterial growth?
lag, log (exponential), stationary, death
35
What factors prevent exponential bacterial growth?
- Oxygen availability
- Nutrient availability
- Temperature
- Waste build-up
- Change in pH (CO2)
36
What are the two main ways of growing microorganisms in bioreactors?
- Batch and continuous fermentation
37
What is batch fermentation?
- MOs are inoculated into a fixed volume of medium.
- As growth takes place, nutrients are used up.
- Biomass and waste products build up.
- As it approaches the stationary phase, growth slows but secondary metabolite production begins.
- The process is stopped before the death phase and products harvested.
- Equipment sterilised and process is repeated.
38
What is continuous fermentation?
- MOs are inoculated into sterile nutrient medium and start to grow.
- Sterile nutrient medium is added continually to the culture once it reaches the exponential point of growth.
- Culture broth is continually removed so that the volume in the bioreactor stays fairly constant. From this, the product is purified.
- Cannot be used in the production of secondary metabolites.
39
Why are enzymes useful in biotechnology?
- Act as catalysts, lowering energy demands.
- Specific.
- Active at low temps.
-Easy to extract by downstream processing.
40
Why are isolated enzymes more beneficial than whole organisms?
- The presence of the organism may lower yield (may use product)
- Enzymes have no nutrient requirements
- Higher concs possible
- Conditions can be made specific to enzyme
- May only want 1 enzyme
41
What are the advantages of extracellular enzymes?
- More robust, less sensitive to conditions
- Easier to get/extract
- Digestive enzymes
- Fewer of them, easier to identify
42
How are products purified from bioreactors?
downstream processing
43
What are some intracellular enzymes that are used as isolated enzymes?
- Glucose oxidase for blood glucose testing.
- penicillin acylase for converting natural penicillin into semi-synthetic drugs which are more effective.
44
What are some advantages of using immobilised enzymes?
- Can be reused, cheaper
- Uncontaminated product
- greater tolerance to temp and pH (less easily denatured), less expensive to run the bioreactor.
- Catalytic properties easier to modify to fit specific reactions/processes e.g long run time or high temps (glucose isomerase)
45
What are some disadvantages of using immobilised enzymes?
- reduced efficiency, immobilisation may reduce activity rate
- Higher initial costs of materials
- Higher initial costs of bioreactors
- More technical issues
46
What are the ways in which enzymes can be immobilised?
- (hydrophilic/ionic) Adsorption to inorganic carrier (e.g clay, silica)
- Entrapment in (gelatin, polysaccharide, carbon etc) matrix
- Covalent/ionic bonds to inorganic carrier. (covalent: carriers with OH/NH2); ionic: cellulose, synthetic polymers.
- Encapsulation in semi-permeable polymer based membrane.
47
What are the advantages and disadvantages of adsorption for enzyme immobilisation?
- Simple and cheap, very accessible enzymes
- Enzymes easily lost
48
What are the advantages and disadvantages of entrapment in matrix?
- Widely applicable
- may be expensive and can be difficult to entrap
49
What are the advantages and disadvantages of surface immobilisation with covalent/ionic bonds?
- Cost varies
- Strongly bound and accessible
- AS of enzyme can be modified in process, reducing effectiveness
50
What are the advantages and disadvantages of encapsulation in a membrane?
- simple, little effect on AS
- can be expensive
- slow diffusion can hold up process
51
How are enzymes immobilised to produce lactose free milk?
- Immobilise lactase in alginate matrix and milk poured through it.
