Cancer Cells

IB Bio, Unit 1 Test - Semester 2

Epithelial Cells

Intestinal Cells

Why is the cell cycle shorter in epithelial cells then in Liver cells

Epithelial cells divide twice a day, whereas liver cells divide only once a year

How to tumor - suppressor genes and proto - oncogenes normally regulate the cell cycle?

Tumor supressor genes turn off cell division if there is a problem. Proto oncogenes turn on the cell cycle. They both work together to repair defective cells and replacing dead ones.

How can tumor suppressor gene and proto - oncogenes failures regulate the cell cycle?

If these can’t work properly, then they cannot control cell division as they should. if cell division goes uncontrolled , then the cells will divide too rapidly.

Mitotic Index Equation

Cells in mitosis / total # of cells

How does finding the mitotic index help identify possible cancerous tissue?

If the mitotic index is higher then it should be, than that would mean cells are dividing more rapidly then they should be.