Most of the cell’s life is spent growing.
The cycle of growth and division is called the
Interphase – period of growth & activity
A. G1 phase is a time of intense growth.
Most of the cells’ life is spent is this
B. S phase – stands for synthesis
An exact copy of each chromosome is
C. G2 phase is the final stage of
Cell is busy duplicating cell organelles.
D. M phase – mitosis – cell division
E. C Phase – cytokinesis – 2 identical
Usual time for the cell cycle – 10 -30 hrs.
Cancer is a malignant growth resulting from
uncontrolled cell division.
Loss of control my be caused by
environmental factors or by changes in
Tumors are masses of tissue that deprive
normal cells of nutrients.
Metatasis occurs in later stages and allows the
cancer cells to spread by using the circulatory
Causes of Cancer
Environmental factors such as cigarette
smoke, air & water pollution, UV
radiation from the sun.
Viral infections may damage genes.
Cancer prevention –
Diet low in fat & high in fiber
Vitamins & minerals – Carotenoids,
vitamins A, C, E, & calcium
1/3 of all malignancies in US.
Skin composed of 2 layers –
Epidermis – surface – composed of
several layers of closely packed cells
Melanin is a pigment that absorbs the
UV rays before they reach basal cells.
Types of Skin Cancer
Squamous cell carcinoma affects cells
throughout the epidermis.
Pink or red tumors
Basal cell carcinoma – cancer cell are
from the layer of epidermis that
replenishes the epithelial cells
Melanomas – cancer of the melanocytes
that protect other cells from the UV rays
of the sun