BIOLOGY 151 Chapter Notes - Chapter 3: Spindle Apparatus, Mitosis, G1 Phase
13 Jun 2018
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CELL CYCLE
● An ordered series of events involving cell growth and cell division that produces 2 new
daughter cells
● Interphase and mitotic phase
○ Interphase: cell grows and DNA is replicated
○ Mitotic phase: the replicated DNA and cytoplasmic contents are separated and the
cell divides
INTERPHASE
● The cell undergoes normal growth processes while also preparing for cell division
● G1 phase: (first gap) little change is visible, the cell is quite active at the biochemical
level
○ The cell is accumulating the building blocks of chromosomal DNA and the
associated proteins and accumulating sufficient energy reserve to complete the
task
● S phase: (synthesis of DNA) DNA replication can proceed through the mechanisms that
result in the formation of identical pairs of DNA molecules (sister chromatids)
○ Centrosome is duplicated
○ The 2 centrosomes will give rise to the mitotic spindle: the apparatus that
orchestrates the movement of chromosomes during mitosis
○ Centrioles: at the right angles to each other, pair of rod-like objects
■ Help organize cell division
● G2 phase: the cell replenishes its energy stores and synthesizes proteins needed for
chromosome manipulation
○ Some cell organelles are duplicated and the cytoskeleton is mantled to provide
resources for the mitotic phase
THE MITOTIC PHASE
● Duplicated chromosomes are aligned, separated, and move into 2 new identical daughter
cells
○ Karyokinesis: first portion of mitotic phase, nuclear division
○ Cytokinesis: second portion, physical separation of the cytoplasmic components
into the 2 daughter cells
● Mitosis: (karyokinesis) is divided into a series of phases- prophase, prometaphase,
metaphase, anaphase, and telophase
○ Prophase: (first phase) the nuclear envelope starts to dissociate into small vesicles
and the membranous organelles (like the golgi complex) fragment and disperse
toward the periphery of the cell
■ The nucleolus disappears
■ Centrosomes starts to move to opposite poles of the cell
■ Microtubules that’ll form the mitotic spindle extend btw the centrosomes
pushing them farther apart as the microtubule fibers lengthen
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Document Summary
An ordered series of events involving cell growth and cell division that produces 2 new daughter cells. Interphase: cell grows and dna is replicated. Mitotic phase: the replicated dna and cytoplasmic contents are separated and the cell divides. The cell undergoes normal growth processes while also preparing for cell division. G1 phase: (first gap) little change is visible, the cell is quite active at the biochemical level. The cell is accumulating the building blocks of chromosomal dna and the associated proteins and accumulating sufficient energy reserve to complete the task. S phase: (synthesis of dna) dna replication can proceed through the mechanisms that result in the formation of identical pairs of dna molecules (sister chromatids) The 2 centrosomes will give rise to the mitotic spindle: the apparatus that orchestrates the movement of chromosomes during mitosis. Centrioles: at the right angles to each other, pair of rod-like objects.
