Cell Cycle

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Transcript Cell Cycle

The Cell Cycle and Mitosis
Cell Cycle
• Interphase
• Mitosis
• Cytokinesis
IMPORTANCE
• 1. Growth
• 2. Tissue Repair
• Means of asexual reproduction for
single celled eukaryotes.
• 3. Keeps chromosome number
constant.
Eukaryotic Cell Cycle
• 1. Most of cell cycle
consists of the
interphase
• 2. Mitosis describes
nuclear division
INTERPHASE
• 1. Cell prepares for mitosis
• 2. Chromosomes duplicate.
• (Chromosomes consist of two DNA
strands).
Eukaryotic Cell Cycle
• Most of cell cycle
consists of the
interphase.
• Mitosis describes
nuclear division.
STAGES OF MITOSIS
• 1. Prophase
• 3. Anaphase
• 2. Metaphase
• 4. Telophase
PROPHASE
• 1. Chromosomes
coil up and become
visible
• 2. Nuclear
membrane
disappears.
• 3. Nucleolus
disappears.
• 4. Spindle appears.
• 5. Centrioles move
toward poles
What’s a spindle?
• Made of the centriole and microtubules
(part of the cytoskeleton)
• The fibers attach to the centromere of
the chromosome and “reel them in”
• Interpretive Dance Time
METAPHASE
Chromosomes become aligned at
the equator of the spindle.
ANAPHASE
• 1. Chromatids
separate.
• 2. Two identical
groups formed.
• 3. Separated
chromatids move to
opposite poles of
the cell.
TELOPHASE
• 1. Chromosomes
uncoil and disappear
• 2. Nuclear
membrane
reappears.
• 3. In plant cells the
cell plate appears.
• Spindle fibers
dissolve
Daughter Cell
• The cytoplasm
becomes divided (a
process called
cytokinesis) and wall
formation produces
two daughter cells.
CRITICAL THINKING
• Human red blood cells develop in the
bone marrow from stem cells, and lose
their nucleus before maturing and being
released into the bloodstream. While
this gives a cell that can be densely
packed with hemoglobin molecules,
what are the consequences as for as
the longevity & its ability to replicate?
CRITICAL THINKING
• Lacking DNA coding,the red blood cells
will not themselves
• be able to replicate
• and we must rely on the stem cells in
the bone marrow to continue red blood
cell production. In addition, the red
blood cells will be limited in life span
and unable to make substantial DNAcoded repairs.