Download Mitosis Notes - Roslyn Public Schools

Name_____________________
Mr. Oggeri
Date________
Period______
Mitosis Notes
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Mitosis
o Purpose: occurs in somatic (body) cells for growth and repair of tissue (ex.
Growing, or healing an injury). Occurs in both plants and animals: asexual
reproduction, (starting a new plant from a stem/leaf of another one)
o Method: mitosis involves one duplication of nuclear material, and one division of
the cell. Chromosome number is maintained (diploid  diploid (normal
chromosome #).
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Daughter cells are identical to each other and to the parent cell.
The cellular life cycle
o Cell Cycle:
o _______________ – mostly the active growth and
metabolism of the cell, but at the end of interphase,
DNA (found in chromosomes) duplicates (makes a
copy of itself)

During interphase, chromosomes are referred to as
______________________ – a loosely scattered arrangement of
________________________
o Mitotic Phase

Period of cell ________________

_____________________ stage in cell
division
Chromosomes and Chromatin

DNA exists in ________________________ form in the
nucleus.

The _____________________ condenses to form
__________________during cell division
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INTERPHASE: The normal growth and development stage of cells
o During this stage cellular activities proceed normally
o There is no DNA ____________________
o Cell produces proteins through protein synthesis
o Cells usually increase in ______________ and __________________
o Chromosomes are not readily visible and are intertwined in the nucleus
o This is known as the “G1 stage” of the cellular cycle. The cell spends the
majority of its life in this stage.
o The cell then enters the “S” or Synthesis stage. During this stage of Interphase
DNA replication occurs and the chromosomes make identical copies of
themselves.
o
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The “G2 stage” is a short period of growth and other preparations necessary for
mitosis.
PROPHASE: At the end of Interphase the chromosomes replicate themselves. This
signals the start of prophase
o During prophase the centrioles migrate to ______________ poles of the cell
o The nuclear membrane breaks ____________ and ___________________
o The chromosomes _____________________ &_________________
o At this point the two replicas of the parent chromosomes are called chromatids
o The two chromatids are joined together in a region known as the centromere
o As prophase continues some of the cells cytoskeleton (made up of
microfilaments) form the spindle fibers
o By the end of prophase an entire network of microfilaments has formed and is
attached to the chromatids at the centromere
o The cell now enters METAPHASE

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METAPHASE

Metaphase begins as the chromatids begin to move towards the ______________ of
the cell

When all the chromatids have reached the center of the cell and begin to separate
_______ begins
What differences can you describe between the 1st Meiotic metaphase and the metaphase
in mitosis?

What differences can you describe between the 2nd Meiotic metaphase and the metaphase
in mitosis?

Anaphase begins with the separation of ___________________ pairs
o Once separated each chromatid is called a ____________________
o By late anaphase an equal number of chromosomes has reached each pole
o The cell membrane begins to change __________ getting thinner in the
middle
Telophase

____________________: during early telophase the chromosomes uncoil

The fragments of the nuclear membrane begin to _______________ around the
chromosomes

The nucleolus reappears

The __________________, and ___________________ in plant cells, begins to form in
the space between the two new nuclei.

The two daughter cells separate by a process called cytokinesis

The cell membrane returns to normal and the new daughter cells enter Interphase

And the cycle continues…..