Transcript Cell Growth & Division Chapter 10 & 11.4 Vocabulary 1. 2. 3. 4. 5. 6. 7. 8. 9. 10. 11. 12. cell division chromatid centromere interphase cell cycle mitosis prophase centriole spindle Metaphase anaphase telophase 13. 14. 15. 16. 17. 18. 19. 20. 21. 22. 23. cytokinesis homologous diploid haploid meiosis tetrad crossing-over gamete cyclin cancer stem cell.

Cell Growth & Division
Chapter 10 & 11.4
Vocabulary
1.
2.
3.
4.
5.
6.
7.
8.
9.
10.
11.
12.
cell division
chromatid
centromere
interphase
cell cycle
mitosis
prophase
centriole
spindle
Metaphase
anaphase
telophase
13.
14.
15.
16.
17.
18.
19.
20.
21.
22.
23.
cytokinesis
homologous
diploid
haploid
meiosis
tetrad
crossing-over
gamete
cyclin
cancer
stem cell
I. Limits to Cell Growth
A. Not enough DNA
1. As a cell increases in size it doesn’t
make more DNA
2. If a cell grows too large, new organelles
can’t get the instructions they need to
function
B. Exchanging Materials: a cell must move
nutrients and wastes across the cell membrane
1. Materials go in and out depending on surface area
2. Food & oxygen is used up depending on volume
3. Ratio of Surface Area to Volume
a. to make it easier, think of the cell as a cube
b. Surface area = length x width x # of sides
Ex: 1cm x 1cm x 6 sides =
c. Volume = length x width x height
Ex: 1cm x 1cm x 1cm =
Double the cell length, what happens?
24/8 or ratio of 3:1
Triple the cell length, what happens?
54/27 or ratio of 2:1
d. As a cell gets larger, volume increases much more
rapidly than surface area.
4. If a cell becomes too big, it cannot exchange
materials across the membrane fast enough.
Cell Size
Surface Area (length
x width x 6)
Volume
(length x width x height)
Ratio of Surface Area to
Volume
II. Cell Division
Draw
A. Chromosomes
1. Carries the genetic information
from one generation to the
next
2. Made up of DNA and proteins
3. Replicated prior to cell division
forming two identical “sister”
chromatids
a. Chromatids are attached by the
centromere
sister
B. Cell Cycle
1. cell cycle = series of events a cell goes through as
it grows and divides
2. A cell grows, prepares for division, and divides to
form two daughter cells, each of which begins the
cycle again
3. Organized into phases:
a. M phase – cell division
1) mitosis – nucleus division
2) cytokinesis – cytoplasm division
b. Interphase
1) G1 phase – cell growth, makes new organelles
2) S phase – DNA replication
3) G2 phase – preparation for mitosis, more growth,
makes more enzymes
4) a cell spends ~90% of its time in interphase
G1 phase
M phase
S phase
DRAW
Fig. 10-4,
pg. 245
G2 phase
DRAW 10-5, pg. 246
Interphase
Centrioles
Nuclear
envelope
Chromatin
Spindle
forming
Prophase
Centromere
Chromosomes (paired
chromatids)
Cytokinesis
Centriole
Spindle
Centriole
Individual
chromosomes
Nuclear
envelope
reforming
Telophase
Anaphase
Metaphase
C. Mitosis
1. Prophase
a. chromatin condenses
b. centrioles separate
c. spindle forms
(microtubules that help
separate chromosomes)
d. Nucleolus disappears,
nuclear membrane
breaks down
2. Metaphase
a. chromosomes line up
across the center of the
cell on spindle
3. Anaphase
a. sister chromatids
separate at
centromeres and
move apart
4. Telophase
a. chromosomes
gather at opposite
ends, new nuclear
envelopes form
D. Cytokinesis
1. To complete the M phase, we
must have cytokinesis =
division of the cytoplasm of
the cell
2. Animal cells - cell membrane
is drawn inward until the
cytoplasm is pinched into 2
new cells
3. Plant cells - cell plate forms
midway between the divided
nuclei; the cell plate gradually
develops into a separating
membrane
E. Cell Cycle Graphic Organizer
Cell Cycle
includes
M phase
Interphase
is divided into
G1 phase
S phase
Mitosis
G2 phase
Prophase
Cytokinesis
is divided into
Metaphase
Anaphase Telophase
Review of Cell Reproduction
Mitosis & Cytokinesis Review Link:
http://highered.mcgrawhill.com/olcweb/cgi/pluginpop.cgi?it=swf::535::535::/sites/dl/free/0072437316/12007
3/bio14.swf::Mitosis%20and%20Cytokinesis
n
n
Check out Cells Alive! and
Biology in Motion from class
website for mitosis review.
http://www.cellsalive.com/
III. Sex Cell Formation - Meiosis
A.
Chromosome Number
1. Humans have 23 pairs of chromosomes, fruit
flies have 4 pairs
2. Homologous = chromosomes that each have a
corresponding chromosome from the oppositesex parent
3. Diploid (2N) = two sets of chromosomes
4. Haploid (N) = one set of chromosomes
Fruit fly chromosomes
Human chromosomes
B. Phases of Meiosis
1. Meiosis = process of forming sex cells, “reduction
and division”
2. Meiosis I (reducing # of chromosomes)
a. Begin with diploid cells (2N)
b. Chromosomes have already been replicated
c. Each chromosome pairs up with its homologous
chromosome to form a tetrad (contains 4
chromatids)
Homologous d. In prophase I in a tetrad, chromatids cross
over one another, exchanging genetic info.
chromosomes
(crossing-over)
DRAW Fig. 11-16, pg. 276
e. Homologous chromosomes are pulled to
opposite sides of the cell, new haploid daughter
cells are formed (N)
Meiosis I
Homologous
chromosomes
Crossing-over
Meiosis II
Prophase II
Metaphase II
Meiosis I results in
two haploid (N)
daughter cells, each
with half the number
of chromosomes as
the original.
Anaphase II
The chromosomes
line up in a similar
way to the
metaphase stage of
mitosis.
The sister
chromatids separate
and move toward
opposite ends of the
cell.
Telophase II
Meiosis II results in
four haploid (N)
daughter cells.
Body cell in a reproductive organ
mother’s
chromosome
father’s
chromosome
chromosomes copied
crossing-over
4 unique gametes
3. Meiosis II (division of chromosomes at
centromere)
a. Meiosis II looks like mitosis except that
crossing-over already occurred
b. Chromosomes line up during metaphase
c. Sister chromatids separate during
anaphase
d. At the end, you have 4 cells that are
genetically different (ex: 4 unique sperm
cells)
DRAW Fig. 11-17, pg. 278
***Use color to show
crossing-over!
C. Gamete Formation
1.
2.
Gamete = sex cell
Males produce sperm
a. haploid
b. each sperm cell can be
involved in
reproduction
3.
Females produce eggs
a. haploid
b. cell divisions are
uneven
c. only one cell receives
most of the cytoplasm
d. other cells are called
polar bodies
IV. Regulating the Cell
A. Controls on Cell Division
1. When cells come into contact with other cells
they respond by not growing
2. Controls on cell growth and cell division can
be turned on and off
3. With an injury, cells at edge of injury are
stimulated to divide rapidly to begin healing
B. Cell Cycle Regulators
1. Regulators = respond to events to speed up or slow
down cell cycle
2. Cyclins = proteins that control the timing of the cell
cycle in eukaryotic cells
A sample of
cytoplasm is
removed from a
cell in mitosis.
The sample is
injected into a
second cell in G2
of interphase.
As a result, the
second cell
enters mitosis.
3. Growth factors – stimulate growth & division
important in embryonic cells and wound
healing
4. Uncontrolled Cell Growth
a. Cancer = a disease of the cell cycle
b. Cancer cells do not respond to signals that
regulate growth of most cells
c. Tumors = masses of cells that damage the
surrounding tissue
d. When a cancer metastasizes, cells have broken
off the tumor and traveled to other parts of the
body
e. Known causes – smoking, tobacco, radiation
exposure, viral infection