Download The Cell Life Cycle

The Cell Life Cycle
Learning Objectives
• Describe the cell life cycle.
• Understand the role of cell division in the cell
cycle.
• Understand the process of terminal differentiation
in cells
• Describe mitosis and cellular differentiation.
• Describe meiosis and contrast it with mitosis.
Cell division
• Cell division is the reproduction of
cells
• Apoptosis is the genetically controlled
death of cells
• Mitosis is the nuclear division of
somatic cells
• Meiosis produces sex cells
Interphase
• Most somatic cells spend the majority of their
lives in this phase
• Interphase includes
– G1
–S
– G2
The Cell Life Cycle
DNA Replication
Mitosis, or nuclear division, has
four phases
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Prophase
Metaphase
Anaphase
Telophase
During cytokinesis, the cytoplasm divides and cell
division ends
Interphase, Mitosis, and Cytokinesis
Interphase, Mitosis, and Cytokinesis
Mitotic rate and cancer
• Generally, the longer the life expectancy of the
cell, the slower the mitotic rate
– Stem cells undergo frequent mitoses
– Growth factors can stimulate cell division
– Abnormal cell division produces tumors or neoplasms
• Benign
• Malignant (invasive, and cancerous)
– Spread via metastasis
– Oncogenes
Chromosomes in Mitosis and Meiosis
Figure 28.6
Differentiation
• Process of specialization
• Results from inactivation of particular genes
• Produces populations of cells with limited
capabilities
• Differentiated cells form tissues
You should now be familiar with:
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•
•
•
The cell life cycle.
Mitosis and cellular differentiation.
Terminal differentiation and the Go phase.
Meiosis and cell ploidy.