Transcript Cell division: Mitosis - Sonoma Valley High School

The Cell cycle & Cell division:
Mitosis
How the cell in the body replicate
Cell Life Cycle
 Each cell has a life
cycle
 The cell grows
 When it gets too big
it prepares to divide
 When the cell divides
it’s genetic material it is
called Mitosis
 When the cells split it
is called cytokinesis
Interphase
 This is the longest part of the
cell’s cycle
 G1 phase – growth
 S phase – DNA replication
 Chromatids are formed
 G2 phase- prepare for
Mitosis
Cell Division
• All cells come
from existing
cells. All living
things create new
cells by dividing.
• Cell division is
different in
prokaryotes and
eukaryotes.
Prokaryotic cell reproducing
Cell Division in Prokaryotes
•
•
Prokaryotes reproduce
by binary fission.
Steps in prokaryote
binary fission.
– Chromosome
replicates
– Cell grows
– New cell wall
develops
– Cell splits into two
cells
Binary Fission
Cell division in Eukaryotic cells
 In Eukaryotic cells the
nucleus divides before the
rest of the cell does.
The process of nuclear
division is called mitosis.
 Mitosis is a multi step
process.
Mitosis
 After the DNA is replicated
inside the nucleus the
chromosomes condense.
Then the nuclear envelope
dissolves.
 Chromosomes are lined up
as sister chromatids in the
center of the cell.
Mitosis continued
 The chromatids
separate into individual
chromosomes
 Then they are moved
apart to opposite sides
of the cell.
Cytokinesis
Each side of the cell
has identical sets of
the chromosomes
 So when the
cytoplasm pinches
apart during
cytokinesis each
daughter cell will have
a complete copy of the
DNA
Control of cell Division
• The cell has checkpoints to insure cell division goes well.
– G1 checkpoint: if the cell is large and health it will divide
– G2 checkpoint: checks that the DNA was copies
correctly
– Mitosis checkpoint: to make sure genetic material was
divided correctly.
Cancer
If one of the proteins that monitors cell growth
is not working properly (usually because of a
mutation in the genetic code) then the cell will
divide uncontrollably. This is cancer.
Write a one paragraph summary of the cell
cycle and cell division, explain why these
are important and what happens if
something goes wrong.