Genetic Modification Flashcards
What is natural selection?
The influence of the environment on survival and/or reproduction so that organisms with some characteristics are more successful at producing offspring than others
Process of natural selection
- environment creates a selection pressure
- animals with features (adaptations) which are best suited for this environment will survive and breed
- they pass on genes to the next generation
Rabbit example
Snowy environment Two colours of rabbit: brown and white White rabbits are more camouflaged and better adapted Predators eat brown rabbits White rabbits survive Breed Pass on genes Over a long period of time, more rabbits are white and evolution can occur
Peppered moth example
- pollution causes lots of smog in forests, covering the trees and creates a section pressure
- mutation causes a dark moth to be produced
- the forest started with an equal number of white moths and black moths
- black moths are better adapted as they are more camouflaged
- the predators ate the white moths as they were easier to see
- black moths are more able to survive
- black moths breed and pass on genes to n cy generation
Process of natural selection ( long version)
- individuals and species produce genetically diverse offspring
- those individuals offspring compete for external things such as sunlight, Good, water and mates, whilst attempting to avoid predators
- offspring with many competitive traits survive and reproduce
- the less competitive die and reproduce less
- the adapted raw frequency increases in population
What is the intifada cause of natural selection in an organism?
Mutation- caused by the selection pressure (changes in the environment)
Antibiotic resistance
- there is a normal population of bacteria
- a mutation occurs, which causes the bacteria to develop antibiotic resistance.
- Antibiotics are applied in attempt to kill the bacteria
- those who are not resistance to the antibiotics are destroyed and die. Those who are resistant are at an advantage.
- the number of non- restraint bacteria decreases as more and more die out
- the bacteria with antibiotic resistance breed and pass on their genes to the next generation
- resistant population increase in number over many generations
If you were a cow farmer, what qualities would u be looking for?
- calm, good producer of milk, good health, healthy diet, food appetite, not susceptible in infection, genes for good milk production
Example of real life genetic modification
Sheep predicting spider silk
Featherless chicken
Glow in the dark animal
Golden rice- vitamin A
Lack of insulin means
You are diabetic- you can’t regulate blood glucose levels
Stages of genetic engineering
1- (insulin) gene cut using restriction enzymes (complimentary sticky ends)
2- vector (plasmid/virus) cut with same restriction enzyme
3- DNA ligase enzyme added to seal overhang making recombiant DNA which is introduced into bacterial cell
4- recombiant DNA molecules replicate and cells divide
5- grow inside a fermenter (optimum temp, PH and glucose)
Ligase
Enzyme used to join sections of DNA with complimentary sticky ends together via S-P backbone
Vector
A structure used to transfer generic material from one organism to another
E.g. plasmid/ bacteriophage
Plasmid
A short loop of circular DNA found in a bacteria. Used In genetic engineering to restrict endonuclease and is where the gene insulin sticks to
How can large volumes of insulin be produced once the vector has taken up volumes of the insulin gene into the bacteria?
- bacteria reproduce inside a fermenter
What is a fermenter?
Enables microorganisms to be grown or ‘cultured’ at optimum PH, temp and nutrient levels
What characteristics would be useful to breed into crop plants?
Insect resistant- prevents loss of crops
Year round growth I.e. greenhouses
Disease resistance- don’t die
Large leaves- take in more sunlight for photosynthesis, large yield
Why should we selectively breed plants?
To produce plants that:
- give a high yield
- are resistant to diseases or pests
- do not bend or snap in the wind
- can resist drought, flooding or frost
- are more nutritious
- have a longer shelf life
Describe the process of how plants are selectively bred
- Plants with desire characteristics are chosen
- These are cross bred- pollen from one plant is placed on the stigma of the other plant
- The seeds are collected and germinated
- The offspring with the inherited characteristics are selected and cross bred again
- The process is repeated over many generations until a new variety is produced with all the desired traits
What are the advantages of selectively breeding plants?
- more efficient farming means cheaper food for the consumer
- we can make a more nutritious product
- less waste and therefore hopefully better for the environment
- improves yield
What are the disadvantages of selectively breeding plants?
- may lead to less genetic variety
- harmful genetic traits which normally get removed from a population through natural selection can become more common
- all offspring are vulnerable to similar diseases
- modern seeds are very expensive
Examples of plants which have been genetically modified
Soya- resistant to herbicide
Bannans- resistant to disease
85% of maize growth in the USA is resistant to insect pests
Golden rice- contains vitamin A. Reducea things such as night blindness
What are the advantages of GM plants?
- extend shelf life
- be restraint to herbicides
- insert vitamins or minerals into crops to make them more nutritious
- produce antibodies
- increase resistance to pests and disease
- increased heat and drought tolerance
- health benefits. I.e golden rice
What are the disadvantages of GM crops?
- creates mono cultures
- no diverse crops
- expensive
- high cost, high input
- yield less than normal crops
- no variation
- unknown risks
Transgenic
An organism that comtsins DNA form different species
What is cloning?
The process of creating a genetically identical copy of an organism. Can occur in plants and animals
Fun facts about cloning
- cloning is an example of asexual reproduction using mitosis
- produces genetically identical organisms
- only one parent is needed
- no gametes
- no mixing or genetic info
- the offspring are genetically identical to eachother and the parent
Cuttings
Gardeners clone plants by taking a cutting from a plant
The cutting when planted will grow into a full plant which is genetically identical to the parent plant
Cloning plants
Can also occur on a comercial scale by tissue culture
Micropropagation
Em
Animal cloning is sometimes referred to as
Fusion cell cloning
What type of reproduction is cloning
Asexual
Stages of animal cloning (Dolly the sheep)
- took sheep A and removed one of its udder cells and from this udder cell, the nucleus was taken
- then they took sheep B and removed an egg cell from its ovaries. From this ovum the nucleus is discarded, leaving an empty nucleus
- the nucleus from sheep A is placed into the empty ovum from sheep B. The new cell, with its new genetic info is given a small electric shock, fusing the cell together
- the cell begins to divide and form an embryo
- the cloned embryo is then inserted into the uterus of sheep c and allowed to mature into a foetus.
Micropropagation
1- explants is scraped from the parent plant.
2-cut and trim to shape
3-explants are placed in agar growth medium containing nutrients and auxins.
5- these plants are kept at optimum conditions for growth
6- samples develop into tiny plantletes
7- plant legs are planted into compost
- more shoots are removed from these explants and then the process repeats until you have thousands of shoots growing
selective breeding in animals
Decide which characteristics are important
Choose parents that show these characteristics
Select the best offspring from parents to breed the next generation
Repeat the process continuously
