1. 10.3 Regulating the Cell Cycle
Lesson Overview
10.3 Regulating the Cell Cycle

2. The cell cycle is controlled by proteins inside and outside the cell.

3. Regulatory Proteins
Internal regulators -only let the cell cycle continue if everything in the cell is OK.
External regulators - proteins that respond to events outside the cell.
Apoptosis = programmed cell death.

4. Cancer is a disorder in which body cells lose the ability to control cell growth.
Cancer cells ignore the signals that regulate the growth of most cells.
As a result, the cells divide uncontrollably to form a mass of cell called a tumor.

5. A benign tumor = noncancerous.
Does not spread to surrounding healthy tissue.
A malignant tumor = cancerous.
Invades and destroys surrounding healthy tissue.
The spread of cancer cells is called metastasis.
Cancer cells absorb nutrients needed by other cells, block nerve connections, and prevent organs from functioning.

6. What Causes Cancer? Cancers are caused by defects in genes.
Some sources of gene defects are:
smoking tobacco
radiation exposure
defective genes
viral infection
random mutation/DNA Replication error

7. Treatments for Cancer Some localized tumors can be removed by surgery.
Many tumors can be treated with targeted radiation.
Chemotherapy is the use of chemicals that kill or slow the growth of cancer cells.

8. Stem Cells Stem cells are unspecialized cells. They have no job yet.
There are two types of stem cells: embryonic and adult stem cells.

9. Embryonic Stem Cells
Embryonic stem cells are found in the inner cells mass of the early embryo.
Embryonic stem cells are pluripotent - have the ability to become most cell types.

10. Adult Stem Cells Adult organisms contain some types of stem cells.
Adult stem cells are multipotent - limited as to what type of cell they can become.
Adult stem cells from a given organ or tissue typically produce only the types of cells that are unique to that tissue.

11. Frontiers in Stem Cell Research
Stem cells offer the potential benefit of using undifferentiated cells to repair or replace badly damaged cells and tissues.
Stem cell research may lead to new ways to repair the cells that are damaged from a heart attack, stroke, and spinal cord injuries.

12. Ethical Issues
Most techniques for harvesting, or gathering, embryonic stem cells cause destruction of the embryo.
Government funding of embryonic stem cell research is an important political issue.
Groups seeking to protect embryos oppose such research as unethical.
Other groups support this research as essential to saving human lives and so view it as unethical to restrict the research.