Modifying organisms Flashcards
Definition of selective breeding?
when humans artificially select plants or animals that are going to breed so that genes for a particular characteristic remains in the population
Why are organisms selectively bred>
- animals with higher milk or meat yield
- crops with disease resistance
- dogs with a good, gentle temperament
- decorative plants with big or unusual flowers
Explain process of selective breeding?
- from excisting stock, select ones with desired characteristics
- breed together
- select the best offspring and breed them together
- continue process for generations as desired trait becomes stronger and stronger until all posses gene
What are the three disadvantages of selective breeding?
- reduces gene pool ( number of differant alleles in a population) as all closely related - inbreeding
- Can cause health problems as increased chance of inheriting genetic defects
- problem if new disease appears becuase not much variation and so if one is effected and killed others are likely to
What does genetic engineering do?
transfer genes between organisms
What is genetic engineering?
transfering a gene responcible for a desired characteristic from one organism’s genome into another organism, so that it also has desired characteristics
Explain how genetic engineering is done?
- useful gene is isolated (cut) from one organism’s genome using restriction enzymes and inserted into a vector
- vector is usually a virus or bacterial plasmid
- when vector is introduced to target organism, useful gene is inserted into its cells
- this occurs at early stage of development so organism can grow with characteristic
What are the worries of genetic engineering?
that changing an organisms gene might accidently create unplanned problems, effectign future generations
What are the disadvantages of genetic engineering?
- could effect wild flowers that live in and arround wild flowers - reducing biodiversity
- not everyone belives they are safe and that there isnt enough evidence for effect on human health
- these GM species or crops may get into the natural environment and out compete native species
What are some pros of genetic engineering?
- increase yield
- people who have lack of nutrients ( less developed countries) can be edited to contain correct nutrients
- already being used with no problems
WHat are the two ways to clone plants?
tissue culture or cuttings
Explain tissue culture?
- few plant cells are put into a growth medium with hormones so grow into new plants - clones of parent plant
- can be made very quickly, small space, all year
- used by scientists to preserve rare plants that are hard to reproduce naturally
What are cuttings?
- gardeners can take cuttings from good parent plants and then plant them to produce genetically identical copies of parent plant
- produced quickly and simply
How can you make animal clones?
using embryo transplants
explain how an embryo transplant takes place?
- sperm cell taken from one animal and egg from another. sperm artificially fertilises eg. embryo that develops is then split many times to form clones before cells specialise
- cloned embryos can then be implanted into lots of other cows where they grow into baby calves
