Download Cancer – Cells Out of Control!

Name ____________________________ Date ______________ Period ________
Biology
Unit 5 – Cancer, Background Paper 5-5
Cancer – Cells Out of Control!
What happens when a cell breaks from the normal cell cycle and becomes cancerous? Simply
put it is uncontrolled mitosis (cell division). The cell stops doing its primary function – being a liver,
brain, lung, blood cell. The cell even stops being one of those specialized cells – stops
differentiating. It is just a tumor cell with one aim, to reproduce. This rogue behavior begins with
just one cell. All cells that result from that first cell are also cancerous. One a mass of these cells has
accumulated it is termed a tumor. The term tumor and cancer are often used synonymously, but
strictly speaking cancer is the disease while a tumor is the growth.
The cancerous cells within the tumor continue to
divide. They may remain within the original tissue (benign)
or they may become invasive and move into neighboring
tissue. At some point a tumor may invade a blood vessel or
lymph duct. If a cancerous cell from the tumor breaks away
and travels to a different part of the body the tumor has
metastasized. Once a tumor has gone through metastasis1 it
is much more difficult to control.
Cell with
proto-oncogene
mutation
Cancer cell
1
2
But how did the cell become
Liver with cancer cells
cancerous in the first place? Two
spread to other parts of
types of genes have been identified
the body,– metastasisas playing a role in tumor
development. The proteins produced by proto-oncogene2
stimulate cell division while those proteins produced by
tumor suppressor genes inhibit cell division. If a mutation
occurs in the region of DNA that is a proto-oncogene it
becomes an oncogene. Oncogenes override the systems that
normally stop cell division and continually stimulate cells to
divide. If a mutation occurs in a tumor suppressor gene it no
longer produces the proteins that signal cells to limit growth.
The result is a cancerous growth (tumor).
http://www.dana-farber.org/abo/news/publications/pop/fall-winter-2004/images/metastasis_1.jpg
http://www.scq.ubc.ca/wp-content/uploads/2006/07/oncogene-formation.jpg
Background5-5,CancerOut of Control2012
Text 2012
Greg Ballog
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Name ____________________________ Date ______________ Period ________
Title of Reading: 5-5 Cancer – Cells Out of Control
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Concept Map of Reading (3 points)
Main Idea
A) What one question do I have about this article?
1 Point
A&B
B) Show or describe the reading to a parent or guardian (Name ___________________).
What comments or questions did they have concerning the reading?
(Biology Homework Time __________)
Background5-5,CancerOut of Control2012
Text 2012
Greg Ballog
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Answers
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