Unit 6 - Cloning and biotechnology Flashcards
Clones
Carry identical genetic material because they are derived from the same orig. DNA
Cloning
Process of producing genetically identical cells or organisms from the cells of existing organisms through nonsexual means
Examples of processes that form genetically identical organisms
Mitosis
Binary fission (bacteria)
Budding (yeast)
Natural plant cloning
Vegetative propagation through runners or suckering
Artificial plant cloning
Artificial vegetative propagation through cuttings or micropropagation (tissue culture)
Vegetative propagation
Ability of plants to reproduce w/out sexual reproduction by producing new plants from existing vegetative structures
Vegetative structures
Non-reproductive tissues e.g. roots, leaves and stems
Cuttings
Cut stem 1/4 “ below internode at 45-60 degrees
Treat cut end w/ rooting hormones
Cover in clear plastic bag
Transfer to another growing medium
Why do you cover cuttings w/ a clear plastic bag
To keep it moist and warm
Explant
A small piece of tissue
Callus
Undifferentiated mass of tissue containing totipotent cells
Micropropagation
Cut out explant from vegetative structures (leaf)
Sterilise explant w. alcohol
Place explant in sterile agar w/ glucose, cytokinins and auxins
Subdivide callus and place on growth medium to induce root growth (prepares plant for transplanting)
Transferred to greenhouse to acclimatise before being planted outside
Advantages of artificial plant cloning
Can produce large no. v. quickly
Can grow plants that dont reproduce easily
No need to wait for seed production
Reproduce sterile plant
Disadvantages of artificial plant cloning
Labour intensive and requires skilled workers
Trial and error to find ideal conditions for growth
Undesirable traits also passed on
Can fail to microbial contamination
Runners
Side stem grows out from bud at the base of the main stem
Creates new bud and grows a vertical stem
Suckering
Grow from shallow roots from buds that are normally dormant
Duing times of stress, buds are activated and suckers form many metres away from parents tree (to avoid stress that triggered growth)
Eventually form clonal patch of new trees
Trees in clonal patch put out new sucker buds
Advantages of natural plant cloning
Large colonies can form quickly
Allows species to survive catastrophic events
Disadvantages of natural plant coning
No natural selection
Susceptible to gentic disease; no variation
Runners vs. suckers
Runners are overground and suckers are underground
Why must the agar used in micropropagation be sterile
Prevents infection
Competition of resources e.g. oxygen/nutrients if other organisms e.g bacteria and fungi are present
Somatic cell
Biological cell forming the body of an organism
Germline cell
Biological cell that gives rise to the gametes of an organism that reproduces sexually
Natural animal reproductive cloning
Some animals can regenerate entire animals from fragments of the orig. (starfish)
Others fragment and form new identical animals as part of their normal reproductive process (flatworms and sponges)
MZ twins form when an early embryo splits and and two foetuses develop from two halves
Artificial animal reproductive cloning
Somatic cell nuclear transfer
Artificial twinning
Somatic cell nuclear transfer
Extract nucleus from somatic cell from Sheep A
Remove nucleus from egg cell from Sheep B
Insert nucleus from A into innoculated egg(electrofusion)
Stimulates to divide in vitro and implant embryo into sheep C
Artificial embryo twinning
Get fertilised egg and allow to divide until 16 cell stage
Harvest embryo and split into smaller ones manually
Implant into surrogate mothers which give birth to identical high quality animals
Advantages of artifical animal cloning
Produce identical clones w/ desirable traits
Stem cell research
Clones so offspring can be produced all year round
Disadvantages of artificial animal cloning
Difficult and time consuming
Destruction of embryos unethical
Clones have shorter life expectancies
No genetic identity so selection pressures affects all
Similarities between AT and SCNT
Produce clones Both have surrogates Divides by mitosis Unnateral Expensive
Differences between AT and SCNT
AT forms several clones at once
Gametes meet outside the body is AT
SCNT involves only maternal DNA
No fertilisation in SCNT
Biotechnology
Industrial exploitation of living micro-organisms (or parts of them) and biological process to produce useful substances for human use
Why are microorganisms used in biotech
Easy/ not labour intensive
Obtain pure products if aseptic technique is followed
Can be easily genetically enginerred to produce spp products
Short life cycle
Simple requirements for growth - can be left w/ little intervention
Can be grown v. quickly
Can be grown on waste material from other processes
Use of microorganism in biological processes
Brewing - anaerobic respiration of yeast Baking - yeast Cheese making - bacteria and rennin Penicillin production - fermentation by fungus Insulin production - GM bacteria Bioremediation
Bioremediation
Using microorganisms to clean up pollution
Convert toxic pollutants to less harmful substances
Advantages of bioremediation
Uses natural systems Less labour and equipment required Treatment can be carried out on site Few waste products produced Less risk of harmful exposure to clean-up personnel
Culturing microorganisms
Sterilisation - Sterilising equipment in an autoclave (15 mins at 121 degrees)
Inoculation - Introducing a sample of microorganisms to the growth medium
Incubation - Place in a warm environment and place agar plate upside down (condensation)