1. 9.3 The Cell Cycle and Cancer
Biology, 9th ed,Sylvia Mader
Chapter 09
9.3 The Cell Cycle and Cancer
Abnormal growth of cells is called a tumor
Benign tumors are not cancerous
Encapsulated
Do not invade neighboring tissue or spread
Malignant tumors are cancerous
Not encapsulated
Readily invade neighboring tissues
May also detach and lodge in distant places (metastasis)
Results from mutation of genes regulating the cell cycle
Development of cancer
Tends to be gradual
May take years before a cell is obviously cancerous
The Cell Cycle

2. The Cell Cycle and Cancer
Biology, 9th ed,Sylvia Mader
Chapter 09
The Cell Cycle and Cancer
Characteristics of Cancer Cells
Lack differentiation
Are non-specialized
Are immortal (can enter cell cycle repeatedly)
Have abnormal nuclei
May be enlarged
May have abnormal number of chromosomes
Often have extra copies of genes
Do not undergo apoptosis
Normally, cells with damaged DNA undergo apoptosis
The immune system can also recognize abnormal cells and trigger apoptosis
Cancer cells are abnormal but fail to undergo apoptosis
The Cell Cycle

3. The Cell Cycle and Cancer
Biology, 9th ed,Sylvia Mader
Chapter 09
The Cell Cycle and Cancer
Characteristics of Cancer Cells
Form tumors
Mitosis is normally controlled by contact with neighboring cells – contact inhibition
Cancer cells have lost contact inhibition
Undergo metastasis
Original tumor easily fragments
New tumors appear in other organs
Undergo angiogenesis
Formation of new blood vessels
Brings nutrients and oxygen to the tumor
The Cell Cycle

4. Biology, 9th ed,Sylvia Mader
Chapter 09
Progression of Cancer
Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display.
New mutations arise, and one cell (brown) has the ability to start a tumor.
primary tumor
lymphatic
vessel
blood
vessel
Cancer in situ. The tumor is at its place of origin. One cell (purple)
mutates further.
lymphatic
vessel
blood
vessel
Cancer cells now have the ability to invade lymphatic and blood vessels
and travel throughout the body.
New metastatic tumors are found some distance from the primary tumor.
The Cell Cycle

5. Cancer Cells vs. Normal Cells
Biology, 9th ed,Sylvia Mader
Chapter 09
Cancer Cells vs. Normal Cells
The Cell Cycle

6. The Cell Cycle and Cancer
Biology, 9th ed,Sylvia Mader
Chapter 09
The Cell Cycle and Cancer
Origin of Cancer
Oncogenes
Proto-oncogenes promote the cell cycle in various ways
If a proto-oncogene is mutated, it may become an oncogene
Tumor suppressor genes inhibit the cell cycle in various ways
If a tumor suppressor gene becomes inactive, it may promote cancer development
Both proto-oncogenes and tumor suppressor genes are normally regulated in coordination with organism’s growth plan
The Cell Cycle

7. The Cell Cycle and Cancer
Biology, 9th ed,Sylvia Mader
Chapter 09
The Cell Cycle and Cancer
Origin of Cancer
Chromosomes normally have special material at each end called telomeres
These get shorter each cell division
When they get very short, the cell will no longer divide
Telomerase is an enzyme that maintains the length of telomeres
Mutations in telomerase gene:
Cause telomeres to continue to lengthen, which
Allows cancer cells to continually divide
The Cell Cycle

8. Biology, 9th ed,Sylvia Mader
Chapter 09
Causes of Cancer
Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display.
Heredity
Radiation
sources
growth
factor
growth factor
Activates signaling
proteins in a stimulatory
pathway that extends
to the nucleus.
Viruses
receptor
protein
Pesticides
and
herbicides
oncogene P
a. Influences that cause mutated proto-oncogenes
(called oncogenes) and mutated tumor
suppressor genes P
activated
protein
signaling P
protein
signaling
Stimulatory
pathway
phosphate
gene product
promotes
cell cycle
b. Effect of growth factor
Inhibitory
pathway
gene product
inhibits
cell cycle
proto-oncogene
Codes for a growth factor,
a receptor protein, or a
signaling protein in a
stimulatory pathway.
If a proto-oncogene
becomes an oncogene,
the end result can be
active cell division.
c. Stimulatory pathway and
inhibitory pathway
tumor suppressor gene
Codes for a signaling
protein in an inhibitory
pathway. If a tumor
suppressor gene mutates,
the end result can be
active cell division.
d. Cancerous skin cell
1,100X
d: © Biophoto Associates/Photo Researchers, Inc.
The Cell Cycle

9. 9.4 Prokaryotic Cell Division
Biology, 9th ed,Sylvia Mader
Chapter 09
9.4 Prokaryotic Cell Division
The prokaryotic chromosome is a ring of DNA
Folded up in an area called the nucleoid
1,000 X the length of cell
Replicated into two rings prior to cell division
Replicated rings attach to the plasma membrane
Binary fission
Splitting in two
Two replicate chromosomes are distributed to two daughter cells
Produces two daughter cells identical to original cell – asexual reproduction
The Cell Cycle

10. Biology, 9th ed,Sylvia Mader
Chapter 09
Binary Fission
Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display.
chromosome
1. Attachment of chromosome to
a special plasma membrane
site indicates that this
bacterium is about to divide.
cell wall
plasma
membrane
cytoplasm
© Dennis Kunkel Microscopy, Inc./Visuals Unlimited
SEM
2,345X
The Cell Cycle

11. Binary Fission The Cell Cycle Biology, 9th ed,Sylvia Mader Chapter 09
Slide #11
Binary Fission
The Cell Cycle
Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display.
chromosome
1. Attachment of chromosome to
a special plasma membrane
site indicates that this
bacterium is about to divide.
cell wall
plasma
membrane
cytoplasm
2. The cell is preparing for binary
fission by enlarging its cell wall,
plasma membrane, and overall
volume.
© Dennis Kunkel Microscopy, Inc./Visuals Unlimited
SEM
2,345X 11

12. Binary Fission The Cell Cycle Biology, 9th ed,Sylvia Mader Chapter 09
Slide #12
Binary Fission
The Cell Cycle
Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display.
chromosome
1. Attachment of chromosome to
a special plasma membrane
site indicates that this
bacterium is about to divide.
cell wall
plasma
membrane
cytoplasm
2. The cell is preparing for binary
fission by enlarging its cell wall,
plasma membrane, and overall
volume.
3. DNA replication has produced
two identical chromosomes.
Cell wall and plasma membrane begin to grow inward.
© Dennis Kunkel Microscopy, Inc./Visuals Unlimited
SEM
2,345X 12

13. Binary Fission The Cell Cycle Biology, 9th ed,Sylvia Mader Chapter 09
Slide #13
Binary Fission
The Cell Cycle
Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display.
chromosome
1. Attachment of chromosome to
a special plasma membrane
site indicates that this
bacterium is about to divide.
cell wall
plasma
membrane
cytoplasm
2. The cell is preparing for binary
fission by enlarging its cell wall,
plasma membrane, and overall
volume.
3. DNA replication has produced
two identical chromosomes.
Cell wall and plasma membrane begin to grow inward.
4. As the cell elongates, the
chromosomes are pulled apart.
Cytoplasm is being distributed
evenly.
© Dennis Kunkel Microscopy, Inc./Visuals Unlimited
SEM
2,345X 13

14. Binary Fission The Cell Cycle Biology, 9th ed,Sylvia Mader Chapter 09
Slide #14
Binary Fission
The Cell Cycle
Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display.
chromosome
1. Attachment of chromosome to
a special plasma membrane
site indicates that this
bacterium is about to divide.
cell wall
plasma
membrane
cytoplasm
2. The cell is preparing for binary
fission by enlarging its cell wall,
plasma membrane, and overall
volume.
3. DNA replication has produced
two identical chromosomes.
Cell wall and plasma membrane begin to grow inward.
4. As the cell elongates, the
chromosomes are pulled apart.
Cytoplasm is being distributed
evenly.
5. New cell wall and plasma
membrane has divided the
daughter cells.
© Dennis Kunkel Microscopy, Inc./Visuals Unlimited
SEM
2,345X 14

15. Functions of Cell Division
Biology, 9th ed,Sylvia Mader
Chapter 09
Functions of Cell Division
The Cell Cycle