there will be a test over chapter 9 and 10 on tuesday, december 9 th. the chapter 10 homework is due...
TRANSCRIPT
• There will be a test over Chapter 9 and 10 on Tuesday, December 9th.
• The Chapter 10 Homework is due on Monday, December 8th at 10:00 pm.
You Must Know
• Ways that the cell cycle are regulated.
• Ways in which the normal cell cycle is disrupted to cause cancer.
Concept 9.3: The eukaryotic cell cycle is regulated by a molecular control system
• The frequency of cell division varies with the type of cell.
• These differences result from regulation at the molecular level.
• Cancer cells manage to escape the usual controls on the cell cycle.
© 2014 Pearson Education, Inc.
Figure 9.UN02
SG1
G2Mitosis
Telophase andCytokinesis
Cytokinesis
MITOTIC (M) PHASE
Anaphase
Metaphase
Prometaphase
Prophase
Experiment 1
S G1
Conclusion Molecules present in the cytoplasmcontrol the progression to S and M phases.
G1 nucleusimmediately enteredS phase and DNAwas synthesized.
SS
Experiment 2
M G1
MM
G1 nucleus beganmitosis withoutchromosomeduplication.
Figure 9.15
M checkpoint
S
M
G1
G2
G1 checkpoint
G2 checkpoint
Controlsystem
Figure 9.16a
G1
G1 checkpoint
Without go-ahead signal,cell enters G0.
G0
With go-ahead signal,cell continues cell cycle.
(a) G1 checkpoint
G1
If a cell receives a go-ahead signal at the G1 checkpoint, it will usually complete the S, G2, and M phases and divide.
Non dividing cells are in the G0 phase.
Figure 9.16b
M checkpoint
M
G1
G2
Prometaphase
Without full chromosomeattachment, stop signal isreceived.
(b) M checkpoint
M
G1
G2
G2
checkpoint
Metaphase
Anaphase
With full chromosomeattachment, go-ahead signalis received.
Separase – an enzyme that allows sister chromatids to separate.
Figure 9.17-4
1 A sample ofhuman connectivetissue is cutup into smallpieces.
Petridish
Scalpels
2 Enzymes digestthe extracellularmatrix, resultingin a suspension offree fibroblasts.
3
4
Cells are transferredto culture vessels. PDGF is added to
half the vessels.
Without PDGF With PDGF Cultured fibroblasts(SEM) 10 m
Platelet-derived growth factor (PDGF) stimulates the division of human fibroblast cells in culture.
Figure 9.18
Anchorage dependence: cellsrequire a surface for division
Density-dependent inhibition:cells form a single layer
Density-dependent inhibition:cells divide to fill a gap andthen stop
20 m 20 m
(a) Normal mammalian cells (b) Cancer cells
Loss of Cell Cycle Controls in Cancer Cells
• Cancer cells do not respond to signals that normally regulate the cell cycle.
• Cancer cells may not need growth factors to grow and divide.– They may make their own growth factor– They may convey a growth factor’s signal without the
presence of the growth factor– They may have an abnormal cell cycle control system
© 2014 Pearson Education, Inc.
Figure 9.19
Breast cancer cell(colorized SEM)
5 m
A normal cell is converted to a cancerous cell by a process called transformation.
1 A tumor growsfrom a singlecancer cell.
Glandulartissue
Tumor
Cancer cellsinvadeneighboringtissue.
2 Cancer cells spreadthrough lymph andblood vessels toother parts of the body.
A small percentageof cancer cells maymetastasize toanother part of the body.
Lymphvessel
Bloodvessel
Cancercell
Metastatictumor
3 4