Cell Regulation

Chapter 5.3

KEY CONCEPTCell 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

• External factors trigger internal factors, which affect the cell cycle.

Cyclins were originally named because their concentration varies in a cyclical fashion during the cell cycle.

Cell division is uncontrolled in cancer.

• Cancer cells form disorganized clumps called tumors.

cancer cellbloodstream

normal cell

– Benign tumors remain clustered and can be removed.– Malignant tumors metastasize, or break away, and can form more tumors.

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 AssignmentThis 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.

– a normal feature of healthy organisms– caused by a cell’s production of self-destructive enzymes– occurs in

developmentof infants webbed fingers

• Apoptosis is programmed cell death.

Bb AssignmentDue 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 occurb. state of the organism following apoptosis.c. the result if apoptosis fails to occur.