CLONING
Process of forming ____________ offspring from a single cell or tissue
A form of ___________ Reproduction
Most successful when cells used are at an early embryonic stage of
development (i.e. the __________stage) before they have begun to
specialize or differentiate.
Cloning is not limited to natural processes. ____________ is a field of
biology that involves the use of living things in engineering, industry and
medicine. This includes cloning plants for use in agriculture.
PLANT CLONING
In 1958, Frederick Steward announced his success in cloning a plant from a
single carrot cell.
By growing individual ______ cells in a nutrient-rich medium containing some
plant hormones, he was able to get the cells to return to an undifferentiated
state. The cells then restarted the process of growth, ____________ and
____________ into new plants cells.
ANIMAL CLONES
An unfertilized egg cell is ________________
The nucleus from a fertilized cell (embryo) is extrated in the _________
stage and inserted into the enucleated cell.
The cell undergoes _________ and in many cases becomes a clone of the
nucleus donor.
On July 5th, 1996, the world’s most famous sheep, _________, was born.
Dolly was the first mammal cloned from an adult body cell.
Dolly was the only successful clone out of _____ attempts.
Today many more species have been cloned from adults: _____, cows, pigs,
dogs, cats, mice, ________, horses, and __________.
There are many problems still with cloned individuals such as; they do not
live as long as normal individuals and often _______ from a variety of health
complications.
Dolly died prematurely of _______________ more common in older sheep.
She also exhibited other signs of premature aging, including arthritis.
In order for cloning to be successful, extraction of the fertilized nucleus
must take place prior to cell specialization.
It is believed that specialized cells have switched off the genetic
information that controls cell division.
CLONING QUESTIONS
1. What is selective breeding? Artificial insemination? Embryo transfer?
2. Explain In vitro fertilization?
3. Explain the steps in cloning a gene in bacteria. Also define recombinant DNA.
4. Explain the difference between therapeutic cloning and reproductive cloning.
5. What is a stem cell? List the three difference sources stem cells have been
used for.
6. What are transgenic organisms?
7. Identify the benefits of cloning plants.
8. What are the applications of transgenic animals?
9. Explain how the use of cloned animals can aid in drug research.
10. Explain why cloning and asexual reproduction are considered to be the same
thing.
11. Identify one drawback of cloning livestock.
12. Why might it be advantageous to clone a prize animal rather than simply
breeding it with other individuals? What might be the disadvantages?
13. What are your thoughts on cloning humans? Should it be done? What are the
advantages and disadvantages?