6.4 Cloning And Biotechnology Flashcards
(21 cards)
How do plants clone naturally?
- asexual reproduction via the meristem = vegetative reproduction
- over time, a young miniature plant forms at these locations and remains attached
- these are clones of their parent and once maturity is reached detached from the mother plant
- they all have the same genotype and phenotype
- some form runners to avoid competition with the parent plant
What are some propagation techniques using vegetative reproduction?
- runner, rhizomes, bulbs, suckers and offsets propagate asexually
- techniques used to propagate desirable species at a less cost
- cuttings can be taken just below the node and dipped in a rooting powder that contains auxin to promote mitosis nd cell differentiation
How can artificial plant clones be produced?
- as many plant cells are totipotent, clones can be produced from any of these cells and therefore clones can be produced via tissue culture
- small piece of plant called an explant is cut - disinfect it and place i a growing medium
- can be used to grow large numbers of plants from a small sample e.g endangered plants
What are the pros and cons of plant cloning?
PROS
- all plants have the same genotype and therefore phenotype
- free from disease
- can genetically modify for immunity
- process is rapid and has a high yeild
- can be transported easily
-rare and endangered species can be propagated to save from extinction
- use of cultivars prevents risk of F1 hybrids that coccur from seed growth = more uniform
- can be grown in any contry in any season
CONS
- expenisve and labour intensive
- susceptible to microbial conatmination
- no genetic variation = low gene pool and more susceptible to change
- risk of unexpected secondary metabolic chemical reaction that could cause stunted growth
What is asexual reproduction in animals?
- parthenogenesis in aphids
- identical twins = egg is fertilized by a sperm and forms a zygote which undergoes an embryo and splits into two identical embryo = identical monozygotic offspring = same genotype initially but mutations can occur every cell cycle that may meen genetic variation can occur
How do you produce an artificial clone in animals with embryo twinning?
- clones of eachother but not their parents
- deliberate division of the embryo into two half embryos
- inserted into a surrogate mother for gestation and births identical twins
- produces offspring with desirable characteristics but cannot predict how many offspring there will be
How do you produce an artificial clone in animals with reproductive cloning?
- somatic cell nuclear transfer
- the animal to be cloned donates a somatic cell
- an egg cell is extracted from the egg donor and enucleated
- the nucleus from the somatic cell is injected into the enucleated egg cell via an electric current
- the hybrid zygote is encouraged to divide by mitosis
The embryo is implanted into the surrogate moter for gestation and birth
The offspring has identical DNA to the somatic cell is
What is therapeutic cloning?
- use cloned cells to replace dead or damaged cells that cause a loss of function in an individual
- embryos cloned as in reproductive cloning but embryos removed and subdivided - they are totipotent and can be cultured and artificiallydifferentiated into any type of cell = specialized cells with the same genome as the sufferer can be loned and replaced
- little clinical progress has been mades been mad
What are the arguments for and against animal cloning?
FOR
- embryo cloning is well accepted in the field of live stock
- many animals with desirable characteristics can be cloned to maximize agricultural output
- can remove less desirable characteristics from the gene pool over time
- help preserve endangered species befoe reintroducing them in the wild
-provide regeerated organs for patients suffering from degenerative disesed as organs are direct genome match so no rejection
AGAINST
- somatic cell nuclear transfer has low sucesss rate
- unkown long term effects of the cloning process - have led to high number of early deaths and genetic abnormalities
- some clones tend to grow abnormally large
- research indicates that cloning disrupts the normal mechanisms/ regulation of gene expression
- pro-life ethics argument as cloning destroys embryos
What is biotechnology?
- biotechnology harnesses the processes in living organisms produce useful products and carry out useful services
- microorganisms often used as they are cheap and readily available and occupy very little space, reproduce quickly
- emerging uses include production of biofuels, vaccines and antibodies, hardy crop plants etc
What are the pros and cons of using microorganisms to make food?
PROS
- microbes more efficient in converting biomass than animals
- microbes reproduce more quickly and growth is not seasonal and can be grown on substrates that are waste products in other industries
- inputs are heap
- fermenters can be set up anywhere in the world
CONS
- fermenter contaminated by other bacteria = ruined product
- sterile technique needed to avoid contamination = expensive
- reproduce quickly therefore mutate quickly and undesirable strands may arise
- products are often high in nucleic acids and can be harmful to humans
-percption that food i nutritious but has little/no flvour
- bacteria can be infected by viruses
What are some aseptic techniques used in culturing microorganisms?
- All work should be carried our in front of a lit bunsen burner with a yellow flame = creates a convection current ad prevents contamination from the air
- Hot agar jelly is poured into a sterilized petri dish and left to cool and set - kills any potential microbes
- Inoculating loop passed through a flame - prevents conatmination
- Petri dish only opened as little as possible at the side facing the flame = decreases contamination risk
- Lid of dish secured with tape and stored upside down = prevents condensation from dropping onto the agar
- Cultures incubated below 25 C in a school lab = restricts growth of harmful pathogens
How do you investigate antibiotics resistance?
- Pre-soak paper discs in different antibiotics solutions - same concentrations
- Spread a sample of diluted bacterial broth onto the surface of a sterile agar plate
- Lightly press the paper discs onto the surface of the agar
- Keep the agar plate in an incubator overnight
- Remove agar plate from incubtor ad examine results
Results = antibiotic discs with the largest clear zone = antibiotic that the bacteria is most resistant to
What is the minimum inhibitory concentration?
- antibiotics used in a controlled dosage
- the minimum inhibitory concentration (MIC) is the lowest concentration of a substance that will inhibit a microorganisms growth
What is the difference between batch and continuous fermentation?
- batch fermentation - microbes grown in batches in the fermentation vessel, once cycle complete the product is removed, fermenter is cleaned and a new batch of microbes is grown = closed culture
- continuous fermentation = microbes grown continuously and products harvested - nutrients added and waste is removed throughout process
How are optimum conditions in the fermenter maintained?
- pH - monitored by probes and acids/alkalis to provide optimum pH for enzyme activity
- temperature - maintained using a water jacket = max enzyme activity and max yeild
- oxygen availability - sterile aire pumped in to provide optimum oxygen to ma respiration and max yield
- nutrient supply - nutrient added and circulated to ensure microbes can acess nutrients required
- agitation - paddles used o ensure even distrubtion of temp, nutrients pH etc
- contamination - fermenters must be steam cleaned between cultures to prevent contamination and increase in therspecific competition
- waste removal - waste constantly removed to provent negative/ toxic effects on growth and microbe productivity
How are populations of microorganisms measured?
- direct counting = individual cells (living and dead) counted via samples
- viable counting - culturing samples of living cells taken and colonies counted
- turbidity = measure of living and dead microbes in a solution via taking an absorbance reading using a colorimeter (turbidity is the measure of cloudiness of a suspension) - as microbes grows, suspension becomes more turbid (cloudy) = less light passes throughon
What are the four phases on a standard population growth curve?
- lag phase - the population size increases slowly as microbes adjust to new environment and start to reproduce
- log phase - high availability of nutrients and space = exponential growth
- stationary phase = population reaches max as limited by resources = BR=DR
- decline phase = lack of nutrients and toxic build up of substances = death rate exceeds reproduction rate
How do you calculate the population growth of bacteria?
- N = N0 x 2^n
- N is final number of bacteria
- N0 is the initial number of bacteria
- n is the number of divisions
What is an immobilised enzyme?
- an immobilized enzyme = enzyme attached to an insoluble material to prevent mixing with the product
- enzymes can be immobilized via attaching to an inert substance OR enclosed in a capsule OR contained within a partially permeable membrane
- often used in industrial processes as enzymes reused and avoids the need to separate enzyme from product in downstream processing
- immboilised enzymes contained in a column were the substrate is filtered in solution, enzyme substrate complexes formed and products produced which flow out of the column
What are the pros and cons of immobilised enzymes?
PROS
- no enzyme in product (uncontaminated) so no need to further process or filter
- enzymes can be reused multiple times = efficient and cost-effective
- have a greater tolerance to temp and pH changes (as immobilisation makes the enzymes more stable)
CONS
- specialist expensive equipment required
- more costly to buy so ess financially worthwhile for smaller industries
- rate of reaction i sometimes lower as cannot mix freely with substrate
