F215: Biotechnology And Gene Technologies Flashcards
What genetic differences can occur between asexually reproduced organisms?
Those that result from mutations.
What I the basis of asexual reproduction in eukaryotes?
Explain this process.
Mitosis.
The genetic material replicate and separates to form two new nuclei, each containing an exact copy of the original DNA.
What is vegetative propagation?
The production of structures in an organism that can grow into new individual organisms.
These offspring contain the same genetic information as the parent and so are clones of the parent.
What is a clone?
A copy of an organism that contains identical genetic material because they are derived from the same original DNA.
How do bacteria reproduce?
Binary fission.
What are the advantages/disadvantages of asexual reproduction?
Advantages:
It is quick, allowing organisms to reproduce rapidly and take advantage of resources in the environment.
It can also be completed if sexual reproduction fails or is not possible.
All offspring have the genetic information to enable them to survive in their environment since the parent survived.
Disadvantages:
It does not produce any genetic variety, so any genetic parental weakness will be in all the offspring.
If the environment chances could potentially be a problem for the plant, such as a new disease causing organism.
What plant undergoes asexual production do you need to know?
English elm, which reproduces when the parent plant is damaged.
How does the English elm survive damage?
They grow root suckers/basal sprouts which grow from meristem tissue in the trunk close to the ground. This is where least damage is likely to have occurred.
Root suckers grow around the original trunk, the suckers then grow into a circle of new elms called a clonal patch.
Describe the disease that attacks the English elm.
Dutch elm disease.
What is a tissue culture?
The separation of cells of any tissue type and 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 methods of vegetative propagation?
Taking cuttings:
A section of stem is cut between leaf joints/nodes.
The cut end is treated with plant hormones and planted.
The cutting forms a clone of the original parent plant.
Very quick.
Grafting:
A shoot section of a woody plant is joined to an already growing root and stem (rootstock).
The graft grows and is identical to the parent but the rootstock is genetically different.
What are the advantages of tissue culture?
Huge numbers produced from a very small amount of plant material.
Disease free.
Cuttings and grafts do not work for all plants.
Describe the process of micro propagation.
A small piece of tissue is taken from the plan to be cloned, usually from the shoot tip - this is the explant.
This is placed on a nutrient growth medium.
Cells in the tissue divide, but dont differentiate. They instead form a mass of undifferentiated cells called a callus.
After a few weeks single callus cells are removed and place on a growing medium containing plant hormones that encourage shoot growth.
After a few weeks the shoots are moved to a different growing me ohm containing different hormones that encourage root growth.
The growing plants are ten moved to a greenhouse to be acclimatised before being planted outside.
What is a callus?
A mass of undifferentiated cells.
What are advantages and disadvantages of plant cloning in agriculture?
Advantages:
Farmers know exactly what the crop produced will be like, can select desirable characteristics.
Costs are reduced as crops are ready to harvest at the same time.
Faster than selective breeding.
Only requires a single valuable plant.
Disadvantages:
Less diversity and more susceptible to disease, less likely to resist change.
What is a cloned animal?
One that has been produced using the same genetic information as another animal.
Such as the animal has the same genotype as the donor organism.
What is a totipotent stem cell?
A cell capable of differentiation into any type Of adult cell found in the organism.
What are the type methods of artificial cloning for animals?
Splitting embryos/identical twins:
Cells from a developing embryo are separated out to form identical organisms.
Nuclear transfer:
A differentiated cell has it’s nucleus placed in an egg which has had it’s own nucleus removed (enucleated)
What are the advantages and disadvantages of animal cloning?
Advantages:
Can clone high value animals in large numbers, eg cows with a high milk yield.
Rare animals can be preserved from extinction.
Disadvantages:
Degradation in animal welfare, overcrowded living etc.
Less likely to respond to a change In the environment.
Unclear if the animals will remain healthy in the long term
What is non reproductive cloning?
What are advantages of this?
Using cloned cells to generate cells, tissues and organs to replace damaged ones.
Advantages:
No rejection from the immune system.
End to donor waiting list.
Cells/tissues that cannot usually be transplanted can now be created.
What is biotechnology?
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 micro organisms used in biotechnology?
They grow rapidly in the most favourable conditions.
Produce proteins or chemicals that can be harvested from the surrounded medium.
Can be genetically engineered to produce specific products.
Grow well at quite low temperatures, lower than those in chemical engineering.
Can be grown anywhere in the world regardless of climate.
Can be grown using nutrient materials that would be useless or toxic to humans, eg waste/CO2
What is a culture?
A growth of micro organisms.
A single species is a pure culture.
A mixture of species is a mixed culture.
Microorganisms can be cultured in a liquid (eg nutrient broth) or a solid surface (eg nutrient afar gel).
What is a closed culture?
The growth of microorganisms in an environment where all conditions are fixed and contained.
No new materials are added and no waste products or organisms are removed.
Describe the standard growth curve for a culture of microorganisms.
Page 160
Lag - constant population, adjust to conditions surrounding them.
Reproduction = death
Log - population increases as space and nutrients increase.
Reproduction > death
Stationary - nutrients decrease, waste products increase, death rate = reproduction rate.
If an open system his is the carrying capacity.
Decline - nutrients are exhausted, levels of toxic waste increase, death rate > reproduction rate.
All organisms will die in a close system eventually.
What does metabolism refer to?
The sum total of all the chemical reactions that go on in an organism.
What are primary metabolites?
Substances produced by an organism as part of it’s normal growth, like amino acids, proteins, enzymes etc.
The production of primary metabolites matches the growth in population of the organism.
Why are secondary metabolites?
Substances produced that are not part of it’s normal growth, like anti biotic chemicals.
Production occurs after the main growth period of the organisms and does not match the growth in population of the organism.
Only a small number of microorganisms produce secondary metabolites.
What conditions are altered in fermenters?
Temperature - enzymes
Type and time of addition of nutrient
O2 conc - do not want anaerobic respiration to occur usually.
pH - reduce activity of enzymes.
Label diagram of fermenter.
Page 162
Describe the two ways to operate a fermenter.
Batch:
Starter population of a micro organism is mixed with a specific quantity of nutrient solution, they are allowed to grow with no further nutrients added.
Eg penicillium fungus
Continuous:
Nutrients are added and products are removed at regular intervals, or continuously.
Eg insulin E. coli bacteria
What is asepsis?
The absence of unwanted microorganisms.
What are aseptic techniques?
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 extracted.
Describe the advantages and disadvantages of batch cultures.
Batch:
Growth rate is slower because nutrient level declines with time.
Easy to set up/maintain/control conditions.
If contamination occurs only one batch is lost.
Less efficient, the fermenter is not in operation all of the time, cleaning etc.
Very useful for processes involving secondary metabolites being produced.
What are the advantages and disadvantages of continuous cultures?
Growth rate is higher as nutrients are continuously added to the fermentation tank.
Set up is difficulter, maintenance of required growing conditions is harder to achieve.
If contamination occurs huge volumes of product can be lost.
More efficient as it operates all the time.
Very useful for processes involving primary metabolite production.
What is an unwanted microorganism?
A contaminant.
Why are contaminants unwanted?
They compete with the culture microorganisms for nutrients and space.
Thus they Reduce the yield of useful products from the culture microorganisms.
May cause spoilage of the product.
May change the conditions, eg by a product changing the pH.
May produce toxic chemicals.
May destroy the culture microorganism and their products.
Describe some aseptic techniques.
Lab level:
Sterilising apparatus either in a flame or by UV light.
Carrying out work in a fine cuboard, so air circulation carries away harmful airborne contaminants.
Cultures of microorganisms kept closed where possible.
Large scale:
Washing/disinfecting fermenters when not in use to remove excess nutrients and kill microorganisms.
Make fermenters of stainless steel to prevent microbes sticking to it.
Sterilising all nutrients before adding to the fermenter prevents adding contaminants.
