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12/5/12
Vocabulary
Cell Reproduction
Chapter 4, Sect. 1-2
1.  cell division
2.  chromatid
3.  centromere
4.  interphase
5.  cell cycle
6.  chromatid
7.  mitosis
8.  prophase
9.  centriole
10.  spindle
11.  metaphase
12.  anaphase
13.  telophase
14.  cytokinesis
15.  homologous
16.  diploid
17.  haploid
18.  fertilization
19.  zygote
20.  meiosis
21.  crossing-over
22.  gamete
23.  growth factor
24.  cancer
I. Cell Division and Mitosis
A.  Why is cell division important?
1.  cell division - makes new cells
2.  this is how unicellular organisms reproduce
3.  this is how multicellular organisms grow
B.  Cell Cycle
1.  Length of Cycle
a.  cell cycle - steps that takes a cell from one cell
division to the next
b.  one complete cell cycle may take 20 minutes to
16 hours depending on the type of cell
2.  Interphase = the time of growth and copying
chromosomes for a cell
a. 
A cell must copy all of its DNA for a new cell
before it divides
b. 
After interphase, cell division begins
G1 phase
M phase
S phase
DRAW
Fig. 2,
Chapter 4
G2 phase
C. Chromosomes
1. 
Carries the genetic information
from one generation to the next
2. 
Made up of DNA and proteins
3. 
Copied prior to cell division
forming two identical sister
chromatids
a. 
Chromatids are attached by the
centromere
Draw Figure 3 in Ch.4
sister
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Interphase
Centrioles
Nuclear
envelope
Chromatin
Spindle
forming
Prophase
Centromere
Chromosomes (paired
chromatids)
Cytokinesis
Centriole
Spindle
Centriole
Individual
chromosomes
Metaphase
Nuclear
envelope
reforming
Telophase
Anaphase
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D.  Mitosis -
4.  Anaphase
when the nucleus divides
to form two identical nuclei
a.  sister chromatids
separate at
centromeres and
move apart
1.  Order of Mitosis: PMAT
2.  Prophase
a.  genetic material forms into
chromosomes you can see
b.  nucleolus disappears
c.  centrioles separate
d.  spindle fibers form
e.  nuclear envelope breaks down
5.  Telophase
a.  chromosomes
gather at opposite
ends, new nuclear
envelopes form
3.  Metaphase
a.  chromosomes line up across
the center of the cell on
spindle
DRAW Figure 5 in Ch.4
E.  Cytokinesis
1.  cytokinesis - division of the
cytoplasm of the cell
2.  Animal cells - cell membrane
is pulled in until the
cytoplasm is pinched into 2
new cells
3.  Plant cells - cell plate forms in
between the two nuclei; the
cell plate gradually develops
into a cell membrane
Interphase
Spindle
forming
Centrioles
Nuclear
envelope
Chromatin
Prophase
Centromere
Chromosomes (paired
chromatids)
Cytokinesis
Centriole
Spindle
Centriole
Individual
chromosomes
Metaphase
Nuclear
envelope
reforming
Telophase
A. 
Sexual Reproduction
1.  Important Vocabulary
a. 
Cell Cycle
b. 
includes
c. 
d. 
Mitosis
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II. Sexual Reproduction & Meiosis
F. Cell Cycle Graphic Organizer
Interphase
Anaphase
Cytokinesis
e. 
Human sperm
is divided into
sexual reproduction - two cells combine DNA to
form a new organism
sperm - male reproductive cell
egg - female reproductive cell
fertilization - the sperm and egg coming together
zygote - the cell that is made from the fertilization
Human egg
Moment of fertilization
is divided into
growth
copying
DNA
Prophase
Metaphase
Anaphase Telophase
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 
B. Chromosome Number
1. 
Homologous = chromosomes that each have a matching
chromosome from the opposite-sex parent
2. 
Diploid cells
Body cells (not sex cells) are diploid
a. 
Diploid = a cell that has 2 sets or pairs of chromosomes (2N)
b. 
Different species have different numbers of chromosomes
1)  Ex: Humans have 23 pairs of chromosomes, fruit flies have 4
c. 
3. 
4. 
Haploid cells
 
C. Meiosis
1.  meiosis = process of forming sex cells
2.  gamete = a sex cell, sperm or egg
3.  A body cell in the reproductive organs (ovaries
or testes) divides to form sex cells.
a. 
Haploid = only one set of chromosomes (N)
a.  2 cells form during meiosis I and then both divide
again during meiosis II
b. 
Humans have 23 chromosomes in each sex cell
 
when two haploid cells (an egg and a sperm) combine, the diploid
zygote develops into a diploid organism
Fruit fly chromosomes
1 diploid body cell divides --> 2 cells, divide --> 4 haploid sex
cells
b.  chromatids cross over one another, exchanging
genetic info (crossing-over)
c.  There is total of 4 cells at the end of meiosis that
have unique DNA
Human chromosomes
Meiosis II
Meiosis I
Homologous
chromosomes
Crossing-over
Prophase II
Meiosis I results in
two haploid (N)
daughter cells, each
with half the number
of chromosomes as
the original.
Body cell in a reproductive organ
mother s
chromosome
father s
chromosome
chromosomes copied
crossing-over
Metaphase II
The chromosomes
line up in a similar
way to the
metaphase stage of
mitosis.
Anaphase II
The sister
chromatids separate
and move toward
opposite ends of the
cell.
Telophase II
Meiosis II results in
four haploid (N)
daughter
16 cells.
IV. Controlling Cell Division
A.  When cells come into contact with other
cells they respond by not growing
B.  Controls on cell growth and cell division
can be turned on and off
C.  With an injury, cells at edge of injury are
stimulated to divide rapidly to begin
healing
DRAW
- use highlighters or
colored pens to
indicate different
chromosomes
4 unique gametes
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D.  Growth factors – chemicals that stimulate
growth & division of cells
1.  important for embryonic cells (for developing
babies) and healing wounds
E.  Uncontrolled Cell Growth
1.  Cancer = a disease of the cell cycle
2.  Cancer cells do not respond to signals that
regulate growth of most cells
3.  Tumors = masses of cells that damage the
surrounding tissue
4.  Known causes – smoking, tobacco, radiation
exposure, viral infection
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