Chapter Ten lecture for Lab Bio on mitosis

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Biology

2. 10–1 Cell Growth
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3. Limits to Cell Growth
Larger cells demand more
from their DNA and they have
trouble moving enough
nutrients and wastes across
the cell membrane.
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4. The rate of transport in and out of the cell is
dependent on the surface area of the cell.
The bigger a cell is the more nutrients it will
need transported in and the more waste it
will need transported out.
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5. A cells volume increases faster
than its surface area.
This makes it more difficult for large cells
to transport materials quickly enough for
the cell to survive.
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7. Before it becomes too large, a growing cell
divides forming two “daughter” cells.
The process by which a cell divides
into two new daughter cells is
called cell division.
Interphase is the period of
growth that occurs
between cell divisions.
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9. 10-2 Cell Division
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10. Eukaryotic cell division occurs in
two major stages.
First, mitosis divides the cell
nucleus.
Second, cytokinesis divides
the cell’s cytoplasm.

11. Chromosomes
Chromosomes
Genetic information is
passed from one
generation to the next on
chromosomes.
Before cell division,
each chromosome
is copied.
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One copy two copies

12. Chromosomes
Each chromosome
consists of two
identical “sister”
chromatids.
Each pair of
chromatids is
attached at an area
called the
centromere.
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Sister
chromatids
Centromere

13. Chromosomes
When the cell divides, the
chromatids separate.
Each daughter cell
gets one chromatid,
so they have the
same number of
chromosomes as
the parent cell.
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14. 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
divides to form two daughter cells,
each of which begins the cycle again
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15. The cell cycle has four phases:
•G1 (First Gap Phase)
•S Phase (DNA Synthesis)
•G2 (Second Gap Phase)
•M Phase (Mitosis)
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16. During G1, the cell
•increases in size
•synthesizes new proteins and
organelles
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17. Events of the Cell Cycle
During the S phase,
chromosomes are replicated
DNA synthesis takes place
Once a cell enters the S phase, it usually
completes the rest of the cell cycle.
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18. Events of the Cell Cycle
The G2 Phase (Second Gap Phase)
organelles and molecules required
for cell division are produced
Once G2 is complete, the cell is ready to
start the M phase—Mitosis
G1 + S + G2 = Interphase
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Cell Cycle
Cell
Division
Active
art

20. Biologists divide mitosis into
four phases:
Prophase
Metaphase
Anaphase
Telophase
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21. Mitosis
Mitosis
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Mitosis
movie

22. Spindle
forming
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Prophase
Chromosomes
(paired
chromatids)
Centromere
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23. Prophase is the first
and longest phase of
mitosis.
The centrioles
separate and take
up positions on
opposite sides of
the nucleus. Chromosomes
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(paired
chromatids)
Spindle
forming
Centromere

24. The centrioles lie in a
region called the
centrosome.
The centrosome
helps to organize
the spindle, a
fanlike microtubule
structure that
helps separate the
chromosomes. Chromosomes
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(paired
chromatids)
Spindle
forming
Centromere

25. Chromatin condenses
into chromosomes.
The centrioles
separate and a
spindle begins to
form.
During prophase,
the nuclear
envelope breaks
down.
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Chromosomes
(paired
chromatids)
Spindle
forming
Centromere

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Centriole
Spindle
Centriole
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Metaphase

27. Metaphase
The second phase of
mitosis is metaphase.
The chromosomes
line up across the
center of the cell.
The centromere
connects to the
poles of the
spindle.
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Centriole
Spindle

28. Individual
chromosomes
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Anaphase

29. Individual
chromosomes
Anaphase
Anaphase is the third
phase of mitosis.
The sister
chromatids are
pulled apart by the
spindle into two
separate
chromosomes.
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30. Copyright Pearson Prentice Hall
Nuclear
envelope
reforming
Telophase

31. Telophase
Telophase is the
fourth and final
phase of mitosis.
Chromosomes
gather at opposite
ends of the cell
and lose their
distinct shape.
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32. In telophase, a new
nuclear envelope
forms around each
cluster of
chromosomes.
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33. Cytokinesis is not a part of mitosis.
Cytokinesis
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Cytokinesis
movie

34. During
cytokinesis, the
cytoplasm
pinches in half.
Each daughter cell
has an identical set of
duplicate
chromosomes
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35. In plants, a structure known as
the cell plate forms midway
between the divided nuclei.
Cell plate Cell wall
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36. The cell plate gradually develops into a
separating membrane.
A cell wall then begins to appear
in the cell plate.
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37. 10-3 Regulating the Cell Cycle
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38. Copyright Pearson Prentice Hall
Controls on Cell Division
Controls on Cell Division
Experiments show that normal cells will
reproduce until they come into
contact with other cells.
When cells come into contact with other cells,
they respond by not growing.
This demonstrates that controls on cell growth
and division can be turned on and off.

39. Controls on Cell Division
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Contact Inhibition

40. Cell Cycle Regulators
The cell cycle is regulated by a specific
protein.
The amount of this protein in the cell rises
and falls in time with the cell cycle.
Scientists called this protein cyclin
because it seemed to regulate the cell
cycle.
Cyclins regulate the timing of the
cell cycle in eukaryotic cells.
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41. Cyclins were discovered during a
similar experiment to this one.
A sample of
cytoplasm
is removed from
a cell
in mitosis.
The sample is
injected
into a second
cell in
G2 of interphase.
As result, the
second
cell enters
mitosis.

42. Internal Regulators
Proteins that respond to events inside
the cell are called internal regulators.
Internal regulators allow the cell cycle to
proceed only when certain processes
have happened inside the cell.
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43. External Regulators
Proteins that respond to events outside
the cell are called external regulators.
External regulators direct cells to speed
up or slow down the cell cycle.
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44. 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.

45. Cancer cells divide uncontrollably and
form masses of cells called tumors that
can damage the surrounding tissues.
Cancer cells may break loose from tumors
and spread throughout the body,
disrupting normal activities and causing
serious medical problems or even death.
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46. Practice questions are not part of the
lecture notes, so you don’t need to copy
them even though they are black.
Have a nice day! ☺

47. Copyright Pearson Prentice Hall
10–1
As a cell increases in size, which of the following
increases most rapidly?
a. surface area
b. volume

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10–1
If an imaginary cube-shaped cell has a length of
6 cm, its ratio of surface area to volume is
a. 1 : 1.
b. 6 : 1.
c. 36 : 1.
d. 1 : 6.

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10–1
The process by which a cell divides into two new
daughter cells is called
a. cell growth.
b. cell division.
c. DNA replication.
d. cell multiplication.

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10–1
When one cell divides in two, what happens to the
surface area to volume ratios in the new cells?
a. There is no change in the amount of material
exchanged.
b. Each new cell can exchange more material
than the original cell.
c. Each new cell can exchange less material than
the original cell.
d. The two new cells cannot be compared to the
original cell.

51. Copyright Pearson Prentice Hall
10–1
When a growing cell undergoes cell division,
each new cell gets
a. half the DNA from the original cell.
b. twice as much DNA as the original
cell.
c. a random sample of the DNA in the original
cell.
d. a full copy of all the DNA in the original cell.

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10-2
The series of events that cells go through as
they grow and divide is called
a. the cell cycle.
b. mitosis.
c. interphase.
d. cytokinesis.

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10-2
The phase of mitosis during which the
chromosomes line up across the center of the
cell is
a. prophase.
b. metaphase.
c. anaphase.
d. telophase.

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10-2
Cytokinesis usually occurs
a. at the same time as telophase.
b. after telophase.
c. during interphase.
d. during anaphase

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10-2
DNA replication takes place during the
a. S phase of the cell cycle.
b. G1 phase of the cell cycle.
c. G2 phase of the cell cycle.
d. M phase of the cell cycle.

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10-2
During mitosis, “sister” chromatids separate from
one another during
a. telophase.
b. interphase.
c. anaphase.
d. metaphase.

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10-3
The cell cycle is believed to be controlled by
proteins called
a. spindles.
b. cyclins.
c. regulators.
d. centrosomes.

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10-3
Proteins that respond to events inside the cell
are called
a. internal regulators.
b. external regulators.
c. cyclins.
d. growth factors.

59. Copyright Pearson Prentice Hall
10-3
Once a multicellular organism reaches adult
size, the cells in its body
a. stop dividing.
b. grow and divide at different rates, depending
on the type.
c. have the same life span between cell
divisions.
d. undergo cell division randomly.

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10-3
One effect of an internal regulator is that a cell
will not begin mitosis until
a. it becomes too large.
b. the cell’s growth is stimulated.
c. it is in physical contact with other
cells.
d. all its chromosomes have been
replicated.

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10-3
One factor common to almost all cancer cells is
a. a lack of cyclin.
b. a defect in gene p53.
c. exposure to tobacco smoke.
d. exposure to radiation.