Mitosis
How do living things grow and
repairthemselves?
Why?
Living things must grow and develop. At times they suffer injuries or damage, or cells simply
wear out. New cells must be formed for the organism to survive. What process must occur to make
a new,properly- functioning cell?
Model 1 – Mitosis as Part of the Cell Cycle
Prophase Metaphase Anaphase Telophase
Mito
sis
(Nuc
lear
Divis
ion)
Nuclear
Centriole
Replicated membrane
chromosome Spindle
(2 sister fibers
chromatids) Cyto
kine
sis
(Cyto
plas
mic
Divis
ion)
1. Refer to Model 1. List the four phases in the mitosis process.
Prophase, metaphase,anaphase,telophase
2. Where is mitosis in the cell cycle? Before G1 and after G2 .
3. What three phases of the cell cycle are considered interphase?
G1,S phase, G2
4. Refer to the cell cycle shown. G0
a. How many cells are present at the beginning of mitosis?
G1
1 *
M
b. How many cells are present at the end of mitosis? (including cytokinesis)
2 G2
S
M itosis
y source was
1
, 5. Refer to the chromosomes in the cells in Model 1.
a. Draw a single chromosome as it appears in Model 1.
/
b. Draw a replicated chromosome as it appears in Model 1.
X
c. How many chromatids are in each replicated chromosome?
2 chromatids per replicated chromosome.
6. How many replicated chromosomes are in the original cell shown in Model 1
duringprophase?
Hint: When counting chromosomes, count “1” for a pair of sister chromatids.
4 replicated chromosomes are in the original cell
7. How many single chromosomes are in each of the new cells in telophase?
4 chromosomes are in each of the new cells.
8. As a group, write a grammatically correct sentence that explains what a chromosome is
andwhy it is important.
Chromosomes is made of DNA wrapped around proteins and contains all the genetic
information of the organism.
9. Refer to the cells in telophase in Model 1.
a. Use a complete sentence to describe what the new cells in telophase might contain
ifreplica- tion of chromosomes did not occur before cytokinesis.
The new cells might contain only half the original number of chromosomes or one cell
mightcontain more chromosomes than the other if replication did not occur before
cytokenisis.
b. If the situation in part a occurred, would the new cells be viable? Explain.
The cells would not be viable because the would not have a complete set of DNA which would affect cell process necessaryfor
survival.
10. The S phase stands for synthesis, which means to make or build something more complex
out of simpler parts. Scientists know that during the S phase DNA is being made in the
nucleus of the cell. Why do you think the cell needs to make more DNA at this time in
thecell cycle?
The cell must copy the chromosome material so there is enough to make two new cells with the correct
chromosome number
How do living things grow and
repairthemselves?
Why?
Living things must grow and develop. At times they suffer injuries or damage, or cells simply
wear out. New cells must be formed for the organism to survive. What process must occur to make
a new,properly- functioning cell?
Model 1 – Mitosis as Part of the Cell Cycle
Prophase Metaphase Anaphase Telophase
Mito
sis
(Nuc
lear
Divis
ion)
Nuclear
Centriole
Replicated membrane
chromosome Spindle
(2 sister fibers
chromatids) Cyto
kine
sis
(Cyto
plas
mic
Divis
ion)
1. Refer to Model 1. List the four phases in the mitosis process.
Prophase, metaphase,anaphase,telophase
2. Where is mitosis in the cell cycle? Before G1 and after G2 .
3. What three phases of the cell cycle are considered interphase?
G1,S phase, G2
4. Refer to the cell cycle shown. G0
a. How many cells are present at the beginning of mitosis?
G1
1 *
M
b. How many cells are present at the end of mitosis? (including cytokinesis)
2 G2
S
M itosis
y source was
1
, 5. Refer to the chromosomes in the cells in Model 1.
a. Draw a single chromosome as it appears in Model 1.
/
b. Draw a replicated chromosome as it appears in Model 1.
X
c. How many chromatids are in each replicated chromosome?
2 chromatids per replicated chromosome.
6. How many replicated chromosomes are in the original cell shown in Model 1
duringprophase?
Hint: When counting chromosomes, count “1” for a pair of sister chromatids.
4 replicated chromosomes are in the original cell
7. How many single chromosomes are in each of the new cells in telophase?
4 chromosomes are in each of the new cells.
8. As a group, write a grammatically correct sentence that explains what a chromosome is
andwhy it is important.
Chromosomes is made of DNA wrapped around proteins and contains all the genetic
information of the organism.
9. Refer to the cells in telophase in Model 1.
a. Use a complete sentence to describe what the new cells in telophase might contain
ifreplica- tion of chromosomes did not occur before cytokinesis.
The new cells might contain only half the original number of chromosomes or one cell
mightcontain more chromosomes than the other if replication did not occur before
cytokenisis.
b. If the situation in part a occurred, would the new cells be viable? Explain.
The cells would not be viable because the would not have a complete set of DNA which would affect cell process necessaryfor
survival.
10. The S phase stands for synthesis, which means to make or build something more complex
out of simpler parts. Scientists know that during the S phase DNA is being made in the
nucleus of the cell. Why do you think the cell needs to make more DNA at this time in
thecell cycle?
The cell must copy the chromosome material so there is enough to make two new cells with the correct
chromosome number
