1. The student is expected to: 5A describe the stages of the cell cycle, including deoxyribonucleic acid (DNA) replication and mitosis, and the importance of the cell cycle to the growth of organisms; 5B examine specialized cells, including roots, stems, and leaves of plants; and animal cells such as blood, muscle, and epithelium;

2. (Continued) 5C describe the roles of DNA, ribonucleic acid (RNA), and environmental factors in cell differentiation; 5D recognize that disruptions of the cell cycle lead to diseases such as cancer; 9C identify and investigate the role of enzymes

3. KEY CONCEPT Cell cycle regulation is necessary for healthy growth.

4. Internal and external factors regulate cell division.
External factors include physical and chemical signals.
Growth factors are proteins that stimulate cell division.
Most mammal cells form a single layer in a culture dish and stop dividing once they touch other cells.

5. Two of the most important internal factors are kinases and cyclins.
External factors trigger internal factors, which affect the cell cycle.

6. Apoptosis is programmed cell death.
a normal feature of healthy organisms
caused by a cell’s production of self-destructive enzymes
occurs in development of infants
webbed fingers

7. Cell division is uncontrolled in cancer.
Cancer cells form disorganized clumps called tumors.
Benign tumors remain clustered and can be removed.
Malignant tumors metastasize, or break away, and can form more tumors.
cancer cell
bloodstream
normal cell

8. Cancer cells do not carry out necessary functions.
Cancer cells come from normal cells with damage to genes involved in cell-cycle regulation.

9. Carcinogens are substances known to promote cancer.
Standard cancer treatments typically kill both cancerous and healthy cells.