Transcript The Cell Cycle

The Cell Cycle
Mitosis
Pg. 204- 210 in your
book
Quick Facts About the Cell
Cycle
 The cell cycle is
common to all living
things
 It is a sequence of
growth and division of
a cell
 Two major periods of
the cell cycle:
I. Interphase
II. Mitosis
Interphase


The time between cell division when
a cell grows and replicates (makes
copies of DNA)
The majority of a cell’s life is spent
in interphase
-Growth Phase I (G1): Proteins are
made, the cell grows and organelles
increase in size and number
-Synthesis Phase (S)- DNA replicates;
the purpose of this is so that the
new cell can have the exact genetic
copy
-Growth Phase (G2)- more proteins
are made, centrioles used for cell
division are copied and being to
make spindles
Cell Cycle
Mitosis
-A continuous process
that has four phases of
the division of the
nucleus
-This is the process
where two daughter
cells are formed, each
containing a complete
set of chromosomes.
Prophase
 The first stage of Mitosis
 The longest mitotic phase
1. Chromosomes appear
because chromatin is
condensing
-What is condensing?
Coiling and getting thicker
2. Centrioles move to the poles of
the cell
3. Centrioles begin to form
spindle
-these attach to the
centromeres which hold
together the sister chromatids
4. Nuclear membrane begins to
disappear
5. Nucleolus disappears
Another picture of prophase
Metaphase
 Chromosomes
become attached to
the spindle fibers by
their centromeres
 Chromosomes line up
across the middle of
the cell
-Also known as the
equator
Another picture of metaphase
Anaphase
 Chromosome separate
and one sister
chromatid of each
pair moves to each
pole of the cell
Another picture of anaphase
Telophase
 Chromosomes arrive
at opposite ends of the
cell
 Two nuclei form
 It’s the reverse of
prophase
More telophase!
Cytokinesis
 Finally the end!
 This is the division of cytoplasm
 This happens in two different
ways
1. In animal cells- the cytoplasm
and plasma membrane pinch in
along the equator to create
cleavage furrow
2. In plant cells- cell plate forms
along the equator
-Plants have a rigid cell wall so
the plasma membrane does not
pinch in
-A cell plate is laid down across
the equator and a cell
membrane forms around each
cell and new cells walls form to
complete the separation.
Plant Cell Cytokinesis vs. Animal
Cell Cytokinesis
 Plant Cell
 Animal Cell


cytokinesis begins with a series of
vesicles that form at the equator of the
cell, which subsequently join until the
cell is divided in two.
cytokinesis starts with a cleavage
furrow or indentation around the middle
that eventually pinches in, dividing the
cell in two
Cell Cycle Summary
Interphase
–
–
–
G1 stage- Growth & development of the
cell
Protein synthesis
S-phase- Chromosome replication via
DNA synthesis
G2 stage- Growth & development
Organelle Replication
Mitosis
Prophase- Replicated chromosomes
condense , Spindle fibers form
Metaphase- Replicated chromosomes
align at center
Anaphase- Sister chromatids separate
Daughter chromosomes move to poles
Telophase- New nuclear membranes
form
Spindle fibers disappear
Cytokinesis- Cell divides into two
daughter cells
Now how am I supposed to
remember all of this?
 Remember PMAT
-Prophase
-Metaphase
-Anaphase
-Telophase
(yes, I know it is simple but it also helped me
remember!)
-Just make sure to remember that Interphase comes
before PMAT and Cytokinesis comes at the end!
Now the fun begins!!
 You get to make a cell cycle booklet!
-You are going to make a booklet of the cell cycle, making sure to include
interphase and mitosis
-Interphase should include the 3 stages (draw and briefly describe events for
G1, S and G2 phases)
-Draw, label and briefly describe the stages of mitosis (If you draw it, you must
label it!)
-The last page of your booklet should show cytokinesis for both animal and
plant cells
-Structures to be labeled:
Nucleolus, Centriole, Spindle Fibers, Daughter Cells, Chromatin,
Centromere, Cleavage Furrow, Nucleus, Sister chromatids, Cell plate
Things to really pay attention to that you will be graded on!
-Accuracy
-Neatness
-Making sure all requirements are met above!