19.1

-apoptosis--programmed cell death
 * Definitions**

-telomeres-- the repetative DNA sequence that the chromosomes in the human body end with

-tumor--when cells pile on top of eachother and grow in multiple layers

-carcinogenesis--the development of cancer

-initiation--a single cell goes through a mutation that makes it start to divide repeatedly

-promotion--a tumor develops, the tumor cells continue to divide and under go mutations

-progression--one cell undergoes a mutation and gives it an advantage over other cells- it happens repeatedly until it can invade surrounding tissue

-angiogenesis--the formation of new blood cells

-metastasis--when cells begin to make a tumor far away from the original tumor

-proto-oncogenes--code for proteins that promote the cell cycle and prevent apoptosis

-tumor-suppressor genes--code for proteins that inhibit the call cycle and promote apoptpsis

-oncogenes--once proto-oncogenes mutate and become cancer-causing genes

-growth factor--a signal that activates a cell-signaling pathway resulting in cell division

-oncology--the study of cancer

-oncologist--someone who studies cancer

-carcinomas--cancers of the epithelial tissues and

-sarcomas--cancers that come in muscles and connective tissue

-leukemias--cancers of the blood

-lymphomas--cancers of the lymphatic tissue

-cyclin-- a protein that reguraly increases and decreases in concentration during the cell cycle

1. what characteristics of cancer cells allow them to grow uncontrollably? - cancer cells are immortal. The telomerase continuously rebuilds the telomeres in cancer cells so the telomeres keep a constant length- allowing the cells to keep diving. 2. Mutations in what two types of genes lead to uncontrollable growth? -proto-oncogenes and tumor-suppressor genes 3. What are the most common types of cancer? - there are many different types of common cancer, in the respiratory system lung cancer is the most common, in the digestive system colon cancer is one of the most common along with pancreas, stomach, and esophagus. in the cardiovascular system lukemia and plasma cell tumors are the most common, in the lymphatic system cancers are either Hodgkin or non-Hodgkin. other common cancers are thyroid cancer, spinal tumors, and breast cancer.
 * Questions**