Transcript Mitosis: Cells at Work!!

Mitosis: Cells at Work!!
What is Mitosis?
Part of the cell cycle
 Nuclear cell division during which
chromosomes are equally distributed
to the 2 identical daughter cells that
are formed
 Results in growth
 Continuous process
 4 stages
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What is the cell cycle?
 Continuous
sequence of growth and division
of a cell. 2 parts: Interphase & Mitosis
 Busiest and longest section is INTERPHASE
Phases of Interphase
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G1 phase – Growth and Protein Synthesis
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S phase – DNA Replication
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G2 phase – Checkpoint to make sure cell
is ready to undergo mitosis
Mitosis
Stage 1: Prophase
•Chromatin coils up into
chromosomes
•Nucleus begins to
disappear
•Centrioles migrate to
opposite ends of cells
and spindle forms
What is a
chromosome?
• The condensed form of
the original DNA connected
to its identical copy
• Sister Chromatids
Mitosis
Stage 2: Metaphase
•Chromosomes attach
to spindle fibers
•Chromosomes line up
along the equator of
the spindle
•Very short phase
Mitosis
Stage 3: Anaphase
•Begins as sister
chromatids separate
•Centromeres split
apart
•Chromatids are
pulled to opposite
poles of the cell
Mitosis
Stage 4: Telophase
•Begins as chromatids
reach the poles
•Chromosomes unwind
and spindle breaks
down
•New nuclei form
around each set of
chromosomes
•Plasma membrane
separates
Cytokinesis: Division of the
cytoplasm
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Animal cell
Plasma membrane
pinches along
equator
Forms a cleavage
furrow that
deepens until the
cell is pinched in
two
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Plant cell
Plasma membrane
does not pinch in
b/c of rigid cell
wall
Cell plate forms at
the equator that
divides the
cytoplasm
Cytokinesis: Division of the cytoplasm
I Pour Milk And Tea
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I—Interphase “The Xerox phase”
P—Prophase “Cell PREPARES and
chromosomes become visible”
M—Metaphase “The chromosomes line
up in the MIDDLE”
A—Anaphase “The chromosomes pull
APART”
T—Telophase “The TWO identical
daughter cells separate”
Purpose of Mitosis (Cell Division)
AFTER mitosis, the 2 new daughter cells
will be identical.
 Each new cell receives the correct
number of chromosomes for that
organism (Humans = 46 chromosomes)
 23 from mom, 23 from dad
 When both sets of chromosomes are in
a cell, it is said to be diploid.
 All somatic (body) cells are diploid.
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Applications of Cell Division
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Regeneration of tissue after
transplantation
Regeneration of body parts (ex.
Starfish)
Spinal cord injuries
Specialized cells for
transplantation
Embryo Development
Ensures that the new cells will
make the same proteins as the
old cell!!!