Zusammenfassung der Ressource
Cloning
- asexual reproduction
- Plants can be cloned from cuttings and by tissue culture
- Cuttings
- Gardeners can take cuttings
from good parent plants and
then plant them to produce
genetically identical copies of
the parent plant
- These plants can be produced quickly and cheaply
- Tissue Culture
- This is where a few plant cells are put in a
growth medium with hormones and they
grow in to new plants clones of the parent
- You can make animal clones using embryo transplant
- Farmers can produce cloned offspring from their best bull or cow
- 1. Sperm cells are taken from a prize bull and egg cells from a
prize cow. The sperm are then used to artificially fertilise an egg
cell. The embryo that develops is then split many times before
any cells become specialised
- 2. These cloned embryos can then be
implanted into lots of other cows where
they grow into baby calves
- 3. Hundreds of ideal offspring can
be produced every year from the
best bull and cow
- Adult cell cloning is another way to make a clone
- 1. Adult cell cloning involves taking an
unfertilised egg cell and removing its
genetic material
- 2. A complete set of chromosomes
from an adult body cell (e.g. skin cell) is
inserted into the empty egg cell
- 3. The egg cell is then stimulated by an electric shock this
makes it divide just like a normal embryo
- 4. When the embryo is a ball of cells its
implanted into an adult female to grow into a
genetically identical copy of the original adult
body cell
- Issues surrounding cloning
- You get a reduced gene pool
which means there are fewer
different alleles in a population. If a
population are all closely related
and a new disease appears they
could all be wiped out they may
be no allele to give resistance
- The study of animal clones
will lead to greater
development of the embryo
and of ageing and age related
disorders
- Cloning could preserve endangered spedcies
- The clones may not be as healthy
- Genetic Engineering
- Genetic engineering uses enzymes to cut an paste its genes
- The basic idea is to copy a useful gene from one
organisms characteristic into another
- 1. A useful gene is cut from one organism chromosome using enzymes
- 2. Enzymes are then used to cut another
organisms chromosome and then to insert the
useful gene
- Scientists use this method to do
all sorts of things e.g to produce
insuline
- Genes can be transferred into animals and plants
- Genetically modified
crops have had their
genes modified e.g. to
make them resistant to
viruses
- Sheep have been
genetically engineered to
produce substances like
drugs in there milk
- Genetic disorders like
cystic fibrosis are caused by
faulty genes. Scientists are
trying to insert working
genes into sufferers this is
called gene therapy
- Pros and cons of genetic engineering
- Pros
- GM crops can increase
the yield of a crop making
more food
- People living in developing nations
often lack nutrients in their diets
crops could be engineered to
contain the nutrient that is missing
- GM crops are already being grown without any problems
- Cons
- Some people say GM
crops would affect the
weeds and flowers
reducing farmland
boidiversity
- Not everyone is convinced GM crops are
safe people are worried they may develop
allergies to the food
- A big concern is that the transplanted gene may get out
into the natural environment