Transcript Cloning - singhscience

The first human being has been cloned!
Cloning
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Keyword
Meaning
Clone
Changing the genetic
characteristics of an organism by
manipulating genes and
introducing them into DNA.
Genetic
Modification
In this technique, the nucleus from a
body cell of the adult is removed and
implanted into an egg cell that has
had the nucleus removed.
Nuclear
Transfer
A genetic copy of another single
organism, or group of cells
Inheritance
A term used to describe the passing of
genes from parents to offspring
1. Inheritance
A term used to
describe the passing
of genes from parents
to offspring.
2. Genetic Modification
Changing the genetic
characteristics of an
organism by manipulating
genes and introducing them
into DNA.
3. Clone
A genetic copy of another
single organism, or group of
cells
4. Nuclear Transfer
Most common method of artificial
cloning.
In this technique, the nucleus from
a body cell of the adult is removed
and implanted into an egg cell that
has had the nucleus removed.
Cloning a single adult animal, especially a
mammal, is very complicated.
The most famous animal
clone is Dolly the sheep,
who was born on 5 July
1996.
Dolly was not the first
animal clone, but the first
mammal to be cloned from
an adult cell.
Cloning how is it done?
• Hints
• Every cell in an organism contains all the
genetic information needed to make an
organism.
What is nuclear transfer?
Dolly was created using a technique called nuclear transfer.
In this technique, the nucleus (i.e.
DNA) from a body cell of the adult is
removed.
This nucleus is then inserted into an
egg cell that has had its own nucleus
removed.
The egg cell is then made to divide and develop like a normal
fertilized egg. The important difference is that it only contains the
DNA from one, rather than two, animals.
Task
• Describe the steps of cloning using
diagrams.
• To help you have been given key words
for each step:
1. Adult cell
2. Nutrients
Extension- Write
down a list of
3. Unfertilised egg cell
possible applications
of cloning and the
4. Nucleus Removed
risks associated
with it.
5. Fused
6. Surrogate
Cloning has Many Uses
1. Could help with the shortage of organs
for transplants.
2. Study of animal clones could lead to
greater understanding of the
development of the embryo and of
ageing.
3. Preserve endangered species.
Issues Surrounding Cloning
Cloning mammals leads to a ‘reduced gene
pool’- this means there are fewer
different alleles in a population.
• If populations are all closely related and
a new disease appears, they could all be
wiped out-because there may be no
allele in the population giving resistance
to the disease.
Issues Surrounding Cloning...
Cloned mammals mightn’t live as long- Dolly
the sheep only lived for 6 years
• She was put down because she had lung
disease and she also had arthritis, these
diseases were more usual in older sheep.
• Dolly was cloned from an older sheep, so its
been suggested her ‘true age’ may have
been older.
• But its possible she was just unlucky- and
that her illnesses weren’t linked to her
being a clone.
Issues Surrounding Cloning...
There are other risks and problems
associated with cloning
• The cloning process often fails. It took
hundreds of attempts to clone Dolly.
• Clones are often born with genetic
defects.
• Cloned mammals immune systems are
sometimes unhealthy- so they suffer
from more disease.
Task
• You will work in pairs to do this.
• You need to prepare a 30 second
argument for either for or against
cloning.
• This needs to be written in your group
• One person will do ‘for’ the other
‘against’.
Stem Cells
Quick Questions
1. In terms of cells what do
specialised and
differentiation mean?
2.Name one type of specialised
cell and how it is adapted to
do its job?
stem cells can
differentiate
into any type of
cell
1. In terms of cells what do specialised
and differentiation mean?
Specialised – Cells that have special
characteristics to allow
them to do their job.
Differentiation – In cells, the process
whereby new cells develop
special characteristics to
allow them to do their job.
2. Name one type of specialised cell
• Red Blood Cell - No nucleus, large
surface area.
• Sperm Cell - Pointy head, tail,
enzymes in the cytoplasm.
• Root hair cell - Large surface area,
thin membrane.
What are stem cells?
The first cells are stem cells.
These are unspecialized cells
capable of developing into many
different types of cell.
Stem cells found in embryos are
called embryonic stem cells and
develop into all the different
types of cell in the body.
If stem cells continued to
divide as they were, humans
would end up as a large jellylike blob!
When the embryo contains about 500 cells, the
cells stop being the same and they stop getting
smaller with each division. They start to
differentiate into different types of cell.
stem cell
stem cell
tissue cell
Tissue cells continue to
divide and differentiate,
each time becoming more
and more specialized.
stem cell
tissue cells
Some will become
nerve cells, others
will become blood
cells, muscle cells,
bone cells, etc.
nerve cells
red blood
cells
cardiac muscle
cells
Stem Cells May be Able to cure
Many diseases