The importance of controlled mitosis

n  Controlled mitosis: the ability of the cell to divide at its own rate and time.

n  Crucial to normal growth, development and maintenance for the perpetuity of living things.

n  Eg:

1.      In plants à controlled mitosis occurs at shoots results in growth of plants.

2.      In humanà Malphigian layer of skin divides actively to replace dead and damaged cells.

3.      A lizard with no tail will gain back its tail within some time due to mitosis. Mitosis will produce new cells which will help the lizard to get back its tail.

4.      If our skin is scraped, mitosis will produce new cells to replace back the worn out cells.

5.      If we donate a part of our liver, we will gain back that part of liver too because of mitosis.

Overall, mitosis is required for the normal growth, development and maintenance.

 

Uncontrolled Mitosis-Cancer

Cancer is any malignant growth or tumor caused by abnormal and uncontrolled cell division; it may spread to other parts of the body through the lymphatic system or the blood stream. Cancer is the result of cell not listening to the signals telling it to stop dividing. Cancer cells have a defect in 2 genes ( a gene that allows cancer and a gene that destroys the cancer cell).When mitosis gets out of control, cells divisions are being made continuously, without an end point. As a result, this problem could lead to various types of cancer. If mitosis became uncontrolled tumor grows .

Causes of Cancer

n  Genetic- some forms of cancer like prostate, colon, breast, skin, ovary are suspected to be inherited from the parents

n  Carcinogens- these are chemicals which affect genetic activity and cause cancer, e.g. of carcinogen a diesel exhaust, cigarette smoke, hair dyes, soot, arsenic, benzene and formaldehyde.

n  Radiation- excess exposure to x-ray, gamma-rays and ultra violet rays lead to increase cancer risk.

n  Viruses- some viruses (such as the HPV and HIV-1) cause cancer.