MITOSIS
the key to growth
Mitosis - the division of the nucleus into two
equal sets of genetic information
Basically, simple cell division
Mitosis is part of the Cell Cycle
The cell cycle is divided into 5 phases.
1. Interphase
The Cell Cycle
2. Prophase
3. Metaphase
Mitosis
4. Anaphase
5. Telophase
**This is a moving, continuous process. Stages are for study.
Interphase
Mitosis
Cytokinesis
Interphase
Period of growth and normal cell
activity
Events of Interphase:
•90% of the cell life.
•DNA is in the form of chromatin.
•DNA replicates, making two exact copies of each chromosome.
•2 centrioles appear.
Stages of interphase:
• G1 (Gap 1) – normal cell growth
•S (Synthesis) – DNA synthesis (replication)
•G2 (Gap 2) – prepares for cell division
Interphase
Look for a
distinct
nucleus
Mitosis: Prophase
Three things happen:
Chromatin coils and become visible
chromosomes.
The nuclear membrane breaks down
and disappears
The spindle fibers & centrioles forms
Mitosis: Prophase
Look for
chromosomes
in the center
Mitosis: Metaphase
Chromosomes line up on the “equator”
(in the middle of the cell)
Chromatids attach to the spindle fibers at
the centromere
Mitosis: Metaphase
Look for
chromosomes
lined up on the
“equator”
Mitosis: Anaphase
Chromosomes pull apart in opposite
directions towards the “poles”
This phase ends when the
chromosomes reach the poles.
Mitosis: Anaphase
Look for
chromosomes
in two groups
pulling apart
Mitosis: Telophase
The fourth and final phase of mitosis
The opposite of Prophase
Chromosomes unwind to form chromatin
Two new nuclei form with new membranes
The spindle disappears
Mitosis: Telophase
Look for two groups
of chromosomes
with a cell plate or
cleavage furrow
Cytokinesis
The division of the cytoplasm
Animal cells pinch inward forming a
cleavage furrow.
Plant cells divide from the inside towards
the outside by forming a cell plate which
becomes the cell wall.
Cytokinesis
Animals:
Cleavage furrow
Cell plate
cell wall
Differences in plant and animal cells:
summary
Animals
Plants
centrioles
no centrioles
cleavage furrow
cell plate
cell wall