Interest Grabber
Section 10-1
Getting Through
Materials move through cells by diffusion. Oxygen and food move into
cells, while waste products move out of cells. How does the size of a cell
affect how efficiently materials get to all parts of a cell?
Work with a partner to complete this activity.
1. On a sheet of paper, make a drawing of a cell that has the following
dimensions: 5 cm x 5 cm x 5 cm. Your partner should draw another cell
about one half the size of your cell on a separate sheet of paper.
2. Compare your drawings. How much longer do you think it would take
to get from the cell membrane to the center of the big cell than from the
cell membrane to the center of the smaller cell?
3. What is the advantage of cells being small?
Go to
Section:
Section Outline
Section 10-1
10–1
Cell Growth
A. Limits to Cell Growth
1. DNA “Overload”
2. Exchanging Materials
3. Ratio of Surface Area to Volume
4. Cell Division
SURFACE AREA TO VOLUME
RATIO LAB
Go to
Section:
10-1 Cell Growth
Limits to Cell Growth
2 Reasons why cells divide rather than
continue to grow indefinitely:
1.The larger a cell becomes, the more
demands the cell places on its DNA
2.The cell has more trouble moving
enough nutrients and wastes across the
cell membrane
Go to
Section:
10-1 Cell Growth
Limits to Cell Growth
•DNA store information that controls a
cell’s function.
•DNA is found in the nucleus of the cell.
•Food, oxygen, and water must enter a
cell through the cell membrane
•Waste must exit a cell through the cell
membrane.
Go to
Section:
10-1 Cell Growth
Limits to Cell Growth
•The rate at which things can enter or exit the
cell is dependent on a cell’s surface area.
•Surface area is the total area of the cell
membrane.
•The rate at which food and oxygen are used
up and waste is produced is dependent on the
cell’s volume.
•The surface area : volume ratio limits cell
growth
Go to
Section:
Ratio of Surface Area to Volume in Cells
Section 10-1
Cell Size
Surface Area
(length x width x 6)
Volume
(length x width x height)
Ratio of Surface Area
to Volume
Go to
Section:
10-1 Cell Growth
Limits to Cell Growth
•Volume increases more rapidly than
the surface area. This causes a
decrease in the surface area to
volume ratio
Go to
Section:
10-1 Cell Growth
Division of the Cell
•Cell division is the process by which
a cell divides into two new daughter
cells.
•Before a cell divides, the cell
replicates its DNA. This ensures that
each daughter cell will receive a full
copy of the DNA.
Go to
Section:
Interest Grabber
Section 10-2
Cell Cycle
The cell cycle represents recurring events that take place in the period of
time from the beginning of one cell division to the beginning of the next. In
addition to cell division, the cell cycle includes periods when the cell is
growing and actively producing materials it needs for the next division.
1. Why is the cell cycle called a cycle?
2. Why do you think that it is important for a cell to grow in size during its
cell cycle?
3. What might happen to a cell if all events leading up to cell division took
place as they should, but the cell did not divide?
Go to
Section:
Section Outline
Section 10-2
10–2
Cell Division
A.
B.
C.
D.
Chromosomes
The Cell Cycle
Events of the Cell Cycle
Mitosis
1. Prophase
2. Metaphase
3. Anaphase
4. Telophase
E. Cytokinesis
Go to
Section:
10-2 Cell Division
2 Stages of cell division in eukaryotes:
1.Mitosis
2.Cytokinesis
Mitosis is the division of the nucleus.
Cytokinesis is the division of the
cytoplasm.
Go to
Section:
10-2 Cell Division
Chromosomes
•Chromosomes contain the genetic
information that is passed on from one
generation of cells to the next.
•Chromosomes are made up of DNA and
proteins.
•Human cells have 46 chromosomes.
•Chromosomes are only visible during cell
division.
Go to
Section:
10-2 Cell Division
Chromosomes
•Before cell division, each chromosomes
replicates, creating 2 identical sister
chromatids.
•Each pair of chromatids is attached at an
area called the centromere which is usually
located in the center.
•When a cell divides, the sister chromatids
separate and each new cell receives one of
the sister chromatids.
Go to
Section:
10-2 Cell Division
Chromosomes
Go to
Section:
10-2 Cell Division
The Cell Cycle
•The cell cycle is the series of events
that cells go through as they grow
and divide.
•During the cell cycle a cell grows,
prepares for division, and divides into
two daughter cells, each of which
then begins the cycle again.
Go to
Section:
10-2 Cell Division
The Cell Cycle
The 4 phases of the cell cycle:
1.G1 Phase- Cell Growth
2.S Phase – DNA replication
3.G2 Phase- Preparation for Mitosis
4.M Phase- Mitosis and Cytokinesis
Traditionally, the G1, S and G2 Phases are
called interphase.
Go to
Section:
Figure 10–4 The Cell Cycle
Section 10-2
G1 phase
M phase
S phase
G2 phase
Go to
Section:
10-2 Cell Division
Events in the cell cycle
G1 Phase
1.Cell increases in size.
2.Synthesis of new proteins and
organelles.
Go to
Section:
10-2 Cell Division
Events in the cell cycle
S Phase
1.Synthesis of DNA
2.Chromosomes are replicated
3.Key proteins associated with
chromosomes are synthesized.
Go to
Section:
10-2 Cell Division
Events in the cell cycle
G2 Phase
1. Organelles and molecules
needed for cell division are
produced.
Go to
Section:
Figure 10–5 Mitosis and Cytokinesis
Section 10-2
Spindle
forming
Centrioles
Nuclear
envelope
Chromatin
Interphase
Centromere
Chromosomes
(paired chromatids)
Prophase
Cytokinesis
Go to
Section:
Spindle
Centriole
Telophase
Nuclear
envelope
reforming
Centriole
Individual
chromosomes
Anaphase
Metaphase
10-2 Cell Division
Mitosis
4 Stages of mitosis:
1.Prophase
2.Metaphase
3.Anaphase
4.Telophase
Go to
Section:
10-2 Cell Division
Mitosis
Prophase
1.Chromatin condenses into
chromosomes
2.Centrioles separate to the poles
3.Spindle forms from microtubules
4.Nucleolus disappears
5.Nuclear envelope disappears
Go to
Section:
Figure 10–5 Mitosis and Cytokinesis
Section 10-2
Spindle
forming
Centrioles
Nuclear
envelope
Chromatin
Interphase
Centromere
Chromosomes
(paired chromatids)
Prophase
Cytokinesis
Go to
Section:
Spindle
Centriole
Telophase
Nuclear
envelope
reforming
Centriole
Individual
chromosomes
Anaphase
Metaphase
10-2 Cell Division
Mitosis
Metaphase
1.Chromosomes line up across the center
of the cell
2.Each chromosome attaches to the
spindle at the centromere
Go to
Section:
Figure 10–5 Mitosis and Cytokinesis
Section 10-2
Spindle
forming
Centrioles
Nuclear
envelope
Chromatin
Interphase
Centromere
Chromosomes
(paired chromatids)
Prophase
Cytokinesis
Go to
Section:
Spindle
Centriole
Telophase
Nuclear
envelope
reforming
Centriole
Individual
chromosomes
Anaphase
Metaphase
10-2 Cell Division
Mitosis
Anaphase
1.Centromeres split allowing each
sister chromatid to become a single
stranded chromosome.
2.Chromosomes move toward each
pole
Go to
Section:
Figure 10–5 Mitosis and Cytokinesis
Section 10-2
Spindle
forming
Centrioles
Nuclear
envelope
Chromatin
Interphase
Centromere
Chromosomes
(paired chromatids)
Prophase
Cytokinesis
Go to
Section:
Spindle
Centriole
Telophase
Nuclear
envelope
reforming
Centriole
Individual
chromosomes
Anaphase
Metaphase
10-2 Cell Division
Mitosis
Telophase
1.Chromosomes uncoil.
2.Spindle breaks down
3.Nuclear envelope reforms
4.Nucleolus reforms
Go to
Section:
Figure 10–5 Mitosis and Cytokinesis
Section 10-2
Spindle
forming
Centrioles
Nuclear
envelope
Chromatin
Interphase
Centromere
Chromosomes
(paired chromatids)
Prophase
Cytokinesis
Go to
Section:
Spindle
Centriole
Telophase
Nuclear
envelope
reforming
Centriole
Individual
chromosomes
Anaphase
Metaphase
10-2 Cell Division
Cytokinesis
•Cytokinesis is the division of the cytoplasm
•Cytokinesis usually occurs at the same time as
telophase.
•In animal cells, the cell membrane draws inward
until the cytoplasm is pinched into two equal
parts.
•In plant cells, a cell plate forms half way between
the 2 nuclei and gradually develops into a cell
membrane and cell wall.
Go to
Section:
Figure 10–5 Mitosis and Cytokinesis
Section 10-2
Spindle
forming
Centrioles
Nuclear
envelope
Chromatin
Interphase
Centromere
Chromosomes
(paired chromatids)
Prophase
Cytokinesis
Go to
Section:
Spindle
Centriole
Telophase
Nuclear
envelope
reforming
Centriole
Individual
chromosomes
Anaphase
Metaphase
Concept Map
Section 10-2
Cell Cycle
includes
Interphase
M phase
(Mitosis)
is divided into
is divided into
G1 phase
Go to
Section:
S phase
G2 phase
Prophase
Metaphase
Anaphase
Telophase
Interest Grabber
Section 10-3
Knowing When to Stop
Suppose you had a paper cut on your finger. Although the cut may have
bled and stung a little, after a few days, it will have disappeared, and your
finger would be as good as new.
1. How do you think the body repairs an injury, such as a cut on a
finger?
2. How long do you think this repair process continues?
3. What do you think causes the cells to stop the repair process?
Go to
Section:
Section Outline
Section 10-3
10–3
Regulating the Cell Cycle
A. Controls on Cell Division
B. Cell Cycle Regulators
1. Internal Regulators
2. External Regulators
C. Uncontrolled Cell Growth
Go to
Section:
10-3 Regulating the cell cycle
Controls of Cell Division
•When placed in a petri dish, cells
will divide until they run out of room.
•If more space is created, the cells
will resume cell division.
•This shows that cell growth and
division can be turned on and off
Go to
Section:
Control of Cell Division
Section 10-3
Go to
Section:
10-3 Regulating the cell cycle
Controls of Cell Division
•An example of this is when we cut
our skin or break a bone.
•Some cell like digestive tract cells
and bone marrow cells reproduce
quickly, while other cells like neurons
and cardiac muscle cells cannot
divide.
Go to
Section:
10-3 Regulating the cell cycle
Cell Cycle Regulators
• Cyclins are proteins that regulate the timing of the cell
cycle in eukaryotic cells.
• 2 types of regulatory proteins:
1. Internal regulators: proteins that respond to events
inside the cell (ex: mitosis only happens if
chromosomes have replicated, anaphase, doesn’t
happen if chromosomes aren’t attached to spindle)
2. External Regulators: proteins that respond to events
outside the cell (ex: growth factors important during
embryonic development or wound healing)
Go to
Section:
Figure 10–8 Effect of Cyclins
Section 10-3
The sample is injected
into a second cell in G2
of interphase.
A sample of
cytoplasm
is removed
from a cell
in mitosis.
As a result, the second
cell enters mitosis.
Go to
Section:
10-3 Regulating the cell cycle
Uncontrolled Cell Growth
•Cancer is a disorder in which some of the
body’s own cells lose the ability to control
growth.
•Cancer cells do not respond to the
signals that regulate the growth of most
cells.
•Cancers have many causes such as
smoking tobacco, radiation exposure, viral
infection or defective genes.
Go to
Section:
Videos
Click a hyperlink to choose a video.
Animal Cell Mitosis
Animal Cell Cytokinesis
Video 1
Animal Cell Mitosis
Click the image to play the video segment.
Video 2
Animal Cell Cytokinesis
Click the image to play the video segment.
Go Online
Links on cell growth
Links from the authors on stem cells
Share cell cycle lab data
Interactive test
For links on cell division, go to www.SciLinks.org and enter the Web
Code as follows: cbn-3102.
For links on the cell cycle, go to www.SciLinks.org and enter the Web
Code as follows: cbn-3103.
Interest Grabber Answers
1. On a sheet of paper, make a drawing of a cell that has the following
dimensions: 5 cm x 5 cm x 5 cm. Your partner should draw another cell
about one half the size of your cell on a separate sheet of paper.
2. Compare your drawings. How much longer do you think it would take
to get from the cell membrane to the center of the big cell than from the
cell membrane to the center of the smaller cell?
It would take twice the amount of time.
3. What is the advantage of cells being small?
If cells are small, materials can be distributed to all parts of the cell quickly.
Interest Grabber Answers
1. Why is the cell cycle called a cycle?
It represents recurring events.
2. Why do you think that it is important for a cell to grow in size during its cell
cycle?
If a cell did not grow in size, each cell division would produce progressively
smaller cells.
3. What might happen to a cell if all events leading up to cell division took
place as they should, but the cell did not divide?
Students may infer that a cell that undergoes all sequences of the cell
cycle would grow increasingly larger—to a point at which the cell could no
longer exchange materials with the environment efficiently enough to live.
Interest Grabber Answers
1. How do you think the body repairs an injury, such as a cut on a finger?
The cut is repaired by the production of new cells through cell division.
2. How long do you think this repair process continues?
Cell division continues until the cut is repaired.
3. What do you think causes the cells to stop the repair process?
Students will likely say that when the cut is filled in, there is no room for
more cells to grow.
This slide is intentionally blank.