Cell Theory, Form, and Function

Cell Cycle: Interphase, Mitosis, Cytokinesis


Cell cycle.
Cell cycle.

Interphase, Mitosis, Cytokinesis


Cell Cycle Regulation and Cancer

Cells regulate their cell cycle in two distinct ways:

  • During G1, when the conditions are favorable, certain proteins stimulate the cell to begin copying the DNA (S phase). Likewise, if the cell is not healthy or large enough, or the environmental conditions are not favorable, the cell cycle stops here to prevent cell injury.


  • The cell cycle can also cease during the G2 phase at the DNA replication site. If the DNA is determined to be without blemish, the process continues, if damaged, the cell cycle is suspended until the DNA can be repaired.


Asexual Reproduction




Asexual reproduction produces offspring in four distinct methods:

  • Budding is when offspring begin as outgrowths or “buds” of the parent. When mature, they drop off and grow into a mature adult. Budding is common in Porifera, like sponges.
  • Fragmentation is common in cnidarians and some worms, and occurs when a piece or pieces of an organism are cut off or broken off from the main body. The fragmented piece then grows into an adult.
  • Binary fission is a combination of mitosis and cytokinesis because an organism simply divides into two organisms, especially common in flatworms.
  • Parthenogenesis is the deposition of unfertilized eggs, often by insects, which grow into adults.


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