Transcript 5.3 Regulation of the Cell Cycle

5.3 Regulation of the Cell Cycle
KEY CONCEPT
Cell cycle regulation is necessary for healthy
growth.
5.3 Regulation of the Cell Cycle
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.
5.3 Regulation of the Cell Cycle
• Two of the most important internal factors are kinases
and cyclins.
• External factors trigger internal factors, which affect the
cell cycle.
5.3 Regulation of the Cell Cycle
• Apoptosis is programmed cell death.
– a normal feature of healthy organisms
– caused by a cell’s production of self-destructive
enzymes
– occurs in
webbed fingers
development
of infants
5.3 Regulation of 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
5.3 Regulation of the Cell Cycle
• Cancer cells do not carry out necessary functions.
• Cancer cells come from normal cells with damage to
genes involved in cell-cycle regulation.
5.3 Regulation of the Cell Cycle
• Carcinogens are substances known to promote cancer.
• Standard cancer treatments typically kill both cancerous
and healthy cells.
5.3 Regulation of the Cell Cycle
Review Questions
1. A substance that causes cancer is ___________
2. What is a harmless tumor called? And those that break
away and spread throughout body?
3. Term for cells that travel to other parts of body.
4. Proteins that stimulate cell division.
5. What is one main difference between a normal cell and
a cancer cell?
6. What are two ways that cell division is regulated in
healthy cells?
5.3 Regulation of the Cell Cycle
Answers
1.
2.
3.
4.
5.
Carcinogen
Benign, malignant
Metastasize
Growth factors
Normal cells stop dividing when they touch each other.
Cancer cells do not respond to normal signals and form
clumps of cells.
6. External factors cause internal factors to help a cell
move through the cell cycle. And programmed cell or
apoptosis occurs then cells need to naturally die.
5.3 Regulation of the Cell Cycle
5.3 Regulation of the Cell Cycle
5.3 Regulation of the Cell Cycle
More examples
of eukaryotes
that reproduce
through asexual
reproducation!
5.3 Regulation of the Cell Cycle
Review Questions:
1. Asexual reproduction results in genetically _________
daughter cells.
2. Binary fission is when a single-celled organism divides
into ____ daughter cells.
3. Through what process do prokaryotes reproduce
asexually? What process do eukaryotes reproduce
asexually?
5.3 Regulation of the Cell Cycle
Answers
1.
2.
3.
4.
Identical
Two
Binary fission
mitosis
5.3 Regulation of the Cell Cycle
5.3 Regulation of the Cell Cycle
5.3 Regulation of the Cell Cycle
5.3 Regulation of the Cell Cycle
All cells have the same DNA!!
• So why do stomach cells function differently than skin
cells if they have the same DNA?
Because different types of cells simply use different genes
contained in the DNA. Skin cells use one part of DNA and
stomach cells use another.
5.3 Regulation of the Cell Cycle
5.3 Regulation of the Cell Cycle