2. Biotechnology
Genetic Engineering

3. Cloning
Cloning is the process in which identical offspring are formed from a single cell or tissue
Many plants have the ability to naturally clone themselves; this is called totipotent (i.e. strawberries, aspen trees)
Most animal cells are not totipotent (except salmanders) but technology has advanced to allow us to clone (i.e. Dolly the sheep)
C.C. the cat
(carbon copy, or copy cat)

4. Cloning There are a few ways that cloning can occur
Nuclear transfer from blastula
Nuclear transfer with electrical or chemical shock
Identical twins
By budding

5. Nuclear transfer from blastula
The nucleus of a cell from a blastula is removed and transplanted into an enucleated unfertilized egg
Enucleated = cells that does not contain a nucleus
- This egg begins to divide by mitosis, eventually forming an organism
Removing the nucleus from a cell

6. Nuclear transfer from blastula
Remove Nucleus
Mitosis
Fertilized Egg
Blastula Stage
Unfertilized Egg
Remove Nucleus
Enucleated Cell
Cell with transplanted nucleus begins to divide by mitosis

7. Why clone from a blastocyst?
Tried at gastrula stage but when they transplanted the nucleus the cell did not divide
Nuclear material must now be fixed and cells would have already started to differentiate

9. Nuclear transfer with electrical shock

10. Dolly and Telomeres
If cells divided without telomeres, they would lose the ends of their chromosomes, and the necessary information they contain.
The telomeres are disposable buffers blocking the ends of the chromosomes, are consumed during cell division, and are replenished by an enzyme, telomerase reverse transcriptase.

11. Identical Twins Are they clones?
After an egg has been fertilized, the newly formed zygote will divide and re-divide through successive mitotic cycles to form the multicellular embryo
If a cell should break free from the forming embryo early in this process (prior to differentiation), it will develop into a second embryo having identical genetic information
Are they clones?

12. Abnormal Cell Division: Cancer
The growth, differentiation and replication of cells is highly controlled
Uncontrolled cell division occurs when cells divide and they do not have a mechanism to stop
This results in a tumor

14. Cancer: Tumors
A benign tumor is a tumor that stays in one place, and often eventually stops dividing
A malignant tumor is a tumor that can metastasize (spread)

15. Carcinogens
Carcinogenic or cancer-causing agents (x-rays, UV light, chemicals and some viruses) can cause mutations in the chromosomes that affect the replication process
Mutations can also occur on their own