Flashcards in Biotechnology and Gene Technologies Deck (48):
Define Vegetative Propogation
The production of structures in an organism that can grow into new individual organisms. These offspring contain the exact genetic information as the parent and so are clones of the parent.
What are clones?
Clones are two or more individuals which have the exact same genetic information as each other.
What are the advantages of asexual reproduction?
Allows fast reproduction to take advantage of the resources around them.
Can be completed if sexual reproduciton fails.
All offspring will have the same genetic information so will be able to survive in the environment as it stands.
What the disadvantages of asexual reproduction?
There is no genetic variation in the offspring so any weaknesses in the parents will also be in the offspring. This means that any changes to the environment will be equally dangerous to all individuals in that population.
How do elm trees reproduce asexually?
Root suckers/basal sprouts form near the base of the tree if the trunk takes damage (such as disease or burning) aproximately 2 months after the damage. They form from the meristem tissue in the trunk close to the ground.
What is the main advantage of basal sprouts for elm trees?
It allows the elm trees to spread over an area forming 'clonal patches' every time one of the trees dies, moving further and further out each time, so long as the resources permit it.
What is the main disadvantage of basal sprouts for elm trees?
They are susceptible to dutch elm disease, just as much as their parents, which is likely the cause of death from the past 100 years. Once they get about 10 cm in diameter, they die in turn, causing more susceptible sprouts to grown and die.
Define 'Tissue Culture'
The separation of cells of any tissue type ad their growth in or on a nutrient medium. In plants, the undifferentiated callus tissue is grown in nutrient medium containing plant hormones that stimulate development of the complete plant.
What are the two main methods of artificial vegitative propogation?
Taking cuttings and grafting
Describe artificial vegitative propogation by taking cuttings
A section of the stem is cut between leaf joints (nodes), treated with plant hormones and planted. This produces a clone of the plant the cutting was taken from.
Describe artifical vegitative propogation by grafting
A shoot section of a woody plant is joined to an already growing root and stem (a rootstock). This graft grows and is a clone of the parent plant, but the rootstock is genetically different to the graft.
Describe artificial vegetative propogation by tissue culture (micropropogation)
Small peice of tissue is taken from the plant to be cloned (from the shoot tip) and paced on a nutrient growth medium. These divide but do not differentiate, forming a callus. After a few weeks single callus cells can be taken and placed in a growth medium to grow, and then are taken and put in a different growth medium after shoots have started to grow. These plants are then put in a greenhouse to grow normally.
Define a cloned animal
One that has been produced using the same genetic infomation as another animal. Such an animal has the same genotype as the donor organism
What are the two methods of artificially cloning an animal?
Splitting embryos (ie. artificial identical twins)
Describe how splitting embryos is able to produce a clone
Cells from an embryo can be sepaqreted to produce two cell masses rather than one, with each cell mass eventually developing into a genetically identical copy of the other.
Describe how nuclear transfer is able to produce a clone
An egg cell is taken and the nucleus is removed (enucleated). This can be from any similar species to the individual being cloned. The nucleus is removed from a cell in the animal being cloned and put inside the egg cell. This now has the full genetic make up of the animal being cloned and can start developing into an embryo.
What are the advantages of cloning?
High value animals (eg in farming) can be cloned in a large scale.
Endangered animals can be cloned in order to preserve a species.
Genetically modified animals are able to be produced on a large scale quickly, knowing that the genes needed are still there.
What are the disadvantages of cloning?
High value, farming animals, are often produced with animal welfare not in mind (eg, chickens that cannot walk).
Excessive genetic uniformity means that the animal is unlikely to be able to adapt to changes in the environment very fast, if at all.
It is unclear the animals will remain healthy in the long term (Dolly died at age 6 suffering from lung cancer from a virus however the post mortem showed nothing out of the ordinary for her age).
What is non-reproductive cloning?
Using cloned cells from the body to produce identical copies of organs and tissues to replace those that have been damaged through disease or accidents.
What are the advantages of using cloned cells to produce organs for tranplants?
It will not be rejected as it is genetically identical to the old/damaged organ.
Could mean an end of waiting for donors to come forward.
Cloned cells can be used to generate any cell type as they are totipotent.
Less dangerous than some major operations such as a heart transplant.
Technology based on biology and involves the exploitation of living organisms or biological processes, to improve agriculture, animal husbandry, food science, medicine and industry.
Why are microorganisms used so widely in various processes?
Grow rapily in favourable conditions
Produce chemicals or proteins that can be harvested
Can be genetically engineered to produce specific products
Grow well at relatively low temperatures
Can be grown anywhere in the world
Tend to produce purer products than processes they are not present in
Can be grown using nutrient materials that would otherwise we wasted
Define A Culture
A growth of microorganisms. This may be a single species (which would be called a pure culture) or a mixture of species (called a mixed culture). Microorganisms can be cultured in a liquid such as nutrient broth, or on a solid surface as nutrient agar gel.
Explain the lag phase of a standard growth curve
Organisms are adjusting to the surrouding conditions. This may mean taking in water, cell expansion, activating specific genes and synthesising specific enzymes. The cells are active but reproducing so population remains fairly constant. The length of this period depends on the growing conditions.
Explain the stationary phase of a standard growth curve
Nutrient levels decrease and waste products like carbon dioxide and other metabolites build up. Individual organisms die at the same rate at which new individuals are being produced. In an open system, this would be the carrying capacity of the environment.
Explain the Log (exponential) phase of a standard growth curve
The population size doubles each generation as every individual has enough space and nutrients to reproduce. In some bacteria, the population can double every 20-30 minutes in these conditions. The length of this phase depends on how quickly the organisms reproduce and take up the available nutrient and space.
Explain the death/decline phase of a standard growth curve
Nutrient exhaustion and increased levels of toxic waste products and metabolites lead to the death rate increasing about the reproduction rate. Eventually, all organisms will die in a closed system.
What does the term fermentation refer to?
The culturing of microorganisms both aerobically and anaerobically in fermentation tanks.
Define Primary Metabolites
Substances produced by an organism as part of its normal growth; they include amino acids, proteins, enzymes, nucleic acids, ethanol and lactate. The production of primary metabolites matches the growth in population of the organism.
Define Secondary Metabolites
Substances produced by an organism that are not part of its normal growth. The antibiotic chemicals produced by a number of microorganisms are almost all secondary metabolites. The production of secondary metabolites usually begins after the main growth period of the organisms and so does not match the growth in population of the organism.
Define Aseptic Technique
Refers to any measure taken at any point in a biotechnological process to ensure that unwanted microorganisms do not contaminate the culture that is being grown or the products that are being extracted.
The absence of unwanted microorganisms
What are the growing conditions that need to be monitored during fermentation?
Type and time of addition of nutrient
What is Batch Culture
Where the mircroorganism starter population is mixed with a specific quantity of nutrient solution, then allowed to grow for a fixed period with no further nutrient added. At the end of the period, the products are removed and the fermentation tank is emptied. Penicillin is produced using batch culter of pinicllium fungus.
What is Continuous Culture
Where nutrients are added to the fermentation tank an d products removed from the fermentation tank at regular intervals - or even, as the name suggests, continuously. Human hormones such as insulin are produced from continuous culture of genetically modified Escherichia Coli Bacteria.
What are the advantages of Batch Culture?
It is easy to set up and maintain
Contamination means only one batch worth is lost.
Very useful for the production of secondary metabolites.
What are the advantages of Continuous Culture?
Growth rate is very high as it is maintained at the log phase of growth.
More efficient as the fermenter operated continuously at a fast rate
Very sueful for producing primary metabolites.
What are the disadvantages of a contaminated culture?
Microoganisms compete with each other for nutrient
Yield of useful products is reduced
May cause spoilage of the product
Toxic chemicals may be produced
Culture organisms and products may be destroyed
Define Immobilisation of Enzymes
Refers to any technique where enzyme molecules are held and separated from the reation mixture. Substrate molecules can bind to the ezymes molecules, and the products formed go back into the mixture leaving the enzyme molecles in place.
What are the advantages of immobilised enzymes?
Enzymes are not present with products so purification costs are low
Enzymes are immediately available for reuse
Enzymes are more stable because of the immobilising matrix so they can do their job just as well in a variety of conditions
What are the disadvantages of immobilised enzymes?
Requires addition time and money to set up.
Enzymes can be less active as they do not mix freely
Any contamination is costly as the whole system would need to be stopped.
What are the methods of immobilising enzymes?
Describe immobilising by adsorption
Enzymes are mixed with an immobilising support and bind to it through hydrophobic and ionic links. Adsorbing agents include porous carbon, glass beads, clays and resins. The bonds are not very strong so some enzymes can leak however as long as their active site doesn't change shape it will not affect the efficiency.
Describe immobilising by covelant bonds
Enzyme molecules covelantly bond to a support, often by linking them together and to an insoluable material (such as clay). A cross linking agent is used, such as gluteraldehyde or sepharose. This does not immobilise very many but stops almost all leakage.
Describe immobilising by entrapment
Enzymes are trapped in a gel bead or a network of fibres. Enzymes are trapped in their natural state so the active site is not affected, however rates can be slowed due to the substrates have to get through the trapping barrier.
Describe immobilising by membrane separation
Enzymes may be physically separated from the substrate mixture by a partially permeable membrane. The enzymes are held on one side and the subtrate is passed through from the other side. The products are small enough to pass back through the membrane.
Refers to the study of the whole set of genetic information in the form of DNA base sequences that occur in the cells of organisms of a particular species. The sequenced genomes or organisms are palces on public databases.