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Cell Regulation
Chapter 5.3
KEY CONCEPT
Cell cycle regulation is necessary for healthy growth.
Internal and external factors regulate cell
division.
• External factors include physical and chemical signals.
• Growth factors are proteins that stimulate cell division.
– Most mammal cells form a single layer in a culture dish and stop
dividing once they touch other cells.
• Two of the most important internal factors are kinases
and cyclins.--- A set of related proteins that regulate the
passage of cells through the cell cycle by forming
complexes with cyclin-dependent protein kinases
Cyclins were originally
named because their
concentration varies in a
cyclical fashion during the
cell cycle.
•
External factors trigger internal factors, which affect the cell cycle.
Cell division is uncontrolled in cancer.
• Cancer cells form disorganized clumps called tumors.
– Benign tumors remain clustered and can be removed.
– Malignant tumors metastasize, or break away, and can form more tumors.
normal cell
cancer cell
bloodstream
Cancer cells do not carry out necessary functions.
•
Cancer cells come from normal cells with damage to genes involved in cell-cycle
regulation.
Carcinogens are substances known to promote cancer.
•
Standard cancer treatments typically kill both cancerous and healthy cells.
Biology presentation
• Click Cell therapy link
normal
Take out a sheet of
paper and answer
each question below
• Cancer cell
• 1. How does the structure of the normal cells
compare with the structure of the cancerous
cells?
• 2. Cancer cells not only appear different from
normal cells but they also divide more rapidly.
Why do you think chemotherapy, a common
treatment for, cancer results in the loss of hair?
Blackboard Assignment
This is due Tuesday, October 25-there will be laptops computers in class on Monday
and Tuesday for you to use to complete this assignment.
• Go to www.classzone.com. Click on Webquest and then on Skin Cancer activity.
Cancer occurs when the cell cycle breaks down. In this WebQuest, you will learn aout
the mosts common cancer in the United States--skin cancer. Explore its causes, how
cells become cancerous, and why prevention is truly the best medicine.
Answer the following questions:
1. What is the relationship between skin cancer and the cell cycle? Your answer must
have a minimum of three sentences.
2. Based on skin cancer facts, provide a persuasive argument to convince your friend
to avoid sunburns. Your arugument must have a minimum of 10 sentences.
3. How do skin cancer treatments work? Your answer must have at least five
sentences.
•
Value 100points.
• Apoptosis is programmed cell death.
– a normal feature of healthy organisms
– caused by a cell’s production of self-destructive enzymes
– occurs in
development
of infants
webbed fingers
Bb Assignment
Due November 4
In this assignment, you will research the role of apoptosis in a developmental process.
Research:
1. Use the Internet to research one of the following processes:
a. the development of neural connections in the human brain
b. the development and maintenance of the human immune system
c. the metamorphosis of a tadpole into an adult frog.
2. Explain the role of apoptosis in your topic in either a hand-written or typed, one -p age summary of
at least 15 sentences total (example: five sentences per answer for a, b and c or 8 sentences to answer
a, 4 sentences to answer b and 3 sentences to answer c and so on).
Your answers must include the following:
a. state of the organism before the apoptopic changes occur
b. state of the organism following apoptosis.
c. the result if apoptosis fails to occur.