Name: ________________________________________________________ Date: _______________ Period: _________
Standard: MC.2.B.8 Describe the main events of the cell cycle: interphase, mitosis and cytokinesis. MC.2.B.9 List in order
and describe the stages of mitosis: prophase, metaphase, anaphase, and telophase.
Bell ringer: _________________________________________________________________________________________
__________________________________________________________________________________________________
__________________________________________________________________________________________________
Cell Division
There are two main reasons as to why a cell must divide instead of continue to grow:
1) Stop DNA “overload”
This means: _________________________________________________________________________________
Before a cell grows too big, it divides forming two “daughter” cells. Each daughter cell has a complete set of DNA
(genetic information). How can this possible if one cell splits to become two?
__________________________________________________________________________________________________
__________________________________________________________________________________________________
The replication of DNA solves the problem of DNA overload because each daughter cell gets one complete set of
genetic information.
2) Make exchange of materials efficient
Cell division allows cells to have a more efficient exchange of materials with the environment by increasing the ratio
of surface area to cell volume.
What is cell division? Go to page 243, read and copy the definition:
__________________________________________________________________________________________________
__________________________________________________________________________________________________
1st step
_________________
Prokaryotes
-separate the contents of the cell in two
parts
Eukaryotes
- happens in 2 stages:
Stage 1: _____________
Stage 2: _____________
Many organisms reproduce by mitosis and cytokinesis. Reproduction by mitosis is classified as asexual, since
the cells produced by mitosis are genetically identical to the parent cell. Mitosis is also the source of new cells when a
multicellular organism grows and develops.
What does asexual mean? ____________________________________________________________________________
__________________________________________________________________________________________________
Chromosomes
Chromosomes are made up of _________ (which carries the cell’s coded genetic information) and proteins.
The cells of every organism have specific number of chromosomes. For example:
Organism
Fruit fly cells
Human cells
Carrots cells
Number of chromosomes
The image below is a karyotype of a male human. It shows the 23 pairs of chromosomes, one pair being the sex
chromosomes (x/y).
Chromosomes are not visible in most cells except during cell division. This is because the DNA and protein
molecules that make up chromosomes are spread throughout the nucleus. At the beginning of cell division, however,
the chromosomes condense into compact, visible structures that can be seen through a light microscope.
Well before cell division, each chromosome is replicated and copied. Because of this, each chromosome
consists of two identical “sister” chromatids.
Chromatids: _______________________________________________________________________________________
__________________________________________________________________________________________________
When the cell divides, the sister chromatids separate from each other. One chromatid goes to each of the new cells.
Each pair of chromatids is attached at an area called the centromere.
Centromere: _______________________________________________________________________________________
__________________________________________________________________________________________________
A human body cell entering cell division contains 46 chromosomes, each of which consists of two chromatids.
The Cell Cycle
The cell cycle is a series of events that cells go through as they grow and divide.
During the cell cycle, a cell grows, prepares for division, and divides to form two daughter cells, each of which
then begins the cycle again.
The cell cycle consists of four phases:
M phase: __________________________________________________________________________________________
__________________________________________________________________________________________________
S phase: ___________________________________________________________________________________________
__________________________________________________________________________________________________
G1: _______________________________________________________________________________________________
__________________________________________________________________________________________________
G2: _______________________________________________________________________________________________
__________________________________________________________________________________________________
During the normal cell cycle, interphase can be quite long, while cell division happens very quickly.
Interphase is divided into 3 stages:
1) ____________
2) ____________
3) ____________
Mitosis is divided into 4 stages:
1)
2)
3)
4)
___________________
___________________
___________________
__________________
Name: ________________________________________________________ Date: _______________ Period: _________
Standard: MC.2.B.8 Describe the main events of the cell cycle: interphase, mitosis and cytokinesis. MC.2.B.9 List in order
and describe the stages of mitosis: prophase, metaphase, anaphase, and telophase.
Bell ringer: _________________________________________________________________________________________
__________________________________________________________________________________________________
__________________________________________________________________________________________________
Prophase: _________________________________________________________________________________________
__________________________________________________________________________________________________
__________________________________________________________________________________________________
Centrioles: __________________________________________________________________________________
__________________________________________________________________________________________________
Spindles: ____________________________________________________________________________________
__________________________________________________________________________________________________
Metaphase: ________________________________________________________________________________________
__________________________________________________________________________________________________
__________________________________________________________________________________________________
Anaphase: _________________________________________________________________________________________
__________________________________________________________________________________________________
__________________________________________________________________________________________________
Telophase: _________________________________________________________________________________________
__________________________________________________________________________________________________
__________________________________________________________________________________________________
Cytokinesis: ________________________________________________________________________________________
__________________________________________________________________________________________________
*cytokinesis usually happens at the same time as telophase.
Cell division in Plants:
Cytokinesis in plant cells is a bit different, because plant cells have a _______________________________________,
which prevents the cleavage furrow from forming. Instead, a ____________________________________ forms in
between both nuclei. By the end of cytokinesis, the cell plate will have become the ______________________________.
Identify and label the stages of mitosis below:
The cells below are dividing. Identify and label each stage of cell division for each picture.
B
D
C
A
A
A= ___________________________
B = ___________________________
C= ___________________________
D= ___________________________
(g)
(h)
A= ___________________________
B = ___________________________
C= ___________________________
D= ___________________________
E= ___________________________
F= ___________________________
G= ___________________________
H= ___________________________
I= ___________________________
(i)
A= ___________________________
B = ___________________________
C= ___________________________
D= ___________________________
E= ___________________________