Cell Cycle Overview

Chapter 8: Cell Cycle Summary

Overview of Topics

• Asexual Reproduction: Includes methods such as binary fission, budding, and fragmentation.
• Cell Division: Focus on Mitosis and Meiosis.
• Stages of the Cell Cycle: PPMAT (Prophase, Prometaphase, Metaphase, Anaphase, Telophase) and Cytokinesis.
• Control of the Cell Cycle: Importance of checkpoints in cancer development.

Key Points on Cell Division

• Mitosis Role:

  • In embryos: growth & differentiation.
  • In adults: growth & repair.

• Stages of the Cell Cycle:

  • G1: Cell growth.
  • S: DNA replication.
  • G2: Preparation for division.
  • M (Mitosis): Division of chromosomes followed by cytokinesis.

• Differences in Plant vs. Animal Cells:

  • Plant cells form a cell plate; animal cells form a cleavage furrow in cytokinesis.
  • No centrioles in plant cells.

Meiosis Overview

• Meiosis I: Formation of tetrads and crossing over occurs.
• Meiosis II: Separation of sister chromatids.
• Results in four haploid daughter cells that are not genetically identical.

Mutation and Karyotypes

• Types of Chromosomal Mutations: Include duplication, translocation, deletion, and inversion.
• Karyotype analysis can determine sex and abnormalities in chromosome numbers.
  • Example: Monosomy is when only one sex chromosome is present.

Control of the Cell Cycle

• Checkpoints: Critical points during the cycle where the cell checks for damage and correct completion of stages.

  • Failure to pass results in apoptosis.

• Cancer: Cells divide uncontrollably, leading to tumors, due to mutations in checkpoint genes like p53.