Summary Chapter 17 - The Cell Cycle

Chapter 17: The Cell Cycle
 A new cell can only be formed by cell division
o  needed to replace cells that die
o  passing on its genetic information to the
next generation of cells
 cell cycle = cycle of duplication and division 
essential mechanism by which all living things
reproduce

Overview of the cell cycle
 Cell cycle: duplicate vast amount of DNA in the
chromosomes and then segregate the copies into
two genetically identical daughter cells
 S phase  chromosome duplication
o  sister chromatids
 sister-chromatid cohesion
 M phase  mitosis
o 1. mitosis / nuclear division
o 2. cytokinesis / cytoplasmic division
o sister chromatids are attached to mitotic spindle = metaphase
 anaphase  separates sister chromatids
 telophase  segregated chromosomes are packaged into separate
nuclei

Phases of the eukaryotic cell cycle:
 G1  S  G2  M
 S phase  DNA synthesis – chromosome duplication
 M phase  mitosis; nuclear division – chromosomes will be
separated into to daughter cells
o cytokinesis = cytoplasmic division
 G1 phase  rest phase – steady state
o gap phase
 G2 phase  no
synthesis is taking place
– preparation; all
components needed for
mitosis are collected
and being prepared;
ensure that conditions
are suitable
 interphase = G1, S, and
G2 together
 Start / restriction point