Download - Chapter 8 handout blks_ 10-18-2011
Chapter 8 CELL DIVISION
I. Why Do Cells Divide?II. The Cell Cycle in ProkaryotesIII. The Cell Cycle in Eukaryotes A. The Cell Cycle and Mitosis and Cancer B. Meiosis 1. Chromosome Numbers 2. The Human Life Cycle 3. Meiotic Cell Division: Meiosis I and II 4. Biological significance C. Comparison of Mitosis and Meiosis
I. Why Do Cells Divide? - for ________________, and _____________
(asexual or sexual)
Paramecium: Asexual reproduction
Yeasts: Asexual reproduction (Budding)
Growth and Development
II. The Cell Cycle and Cell Division in Prokaryotes
*Cell division involves _________________*Chromosomes - packages of ___________, the hereditary
material (+ proteins)
*Gene - a segment of __________ that encodes
for a protein, which in turn is responsible for a particular trait
1attachment site
cellwall
plasmamembrane
circular DNA
3
4
5
2
Fig. 8-3
p. 114
_______________
(asexual reproduction in bacteria)
II. The Cell Cycle in Prokaryotes
III. The Cell Cycle and Cell Division in Eukaryotes
A. The Cell Cycle and Mitosis
Mitosis:
- occurs in ________ cells (body cells)
- daughter cells are genetically __________________
Fig. 8-7 p. 117
The Cell Cycle
in Eukaryotes
G1
G2
S
Fig. 8-10. Cytokinesis in animal cells: _______________________ formation
(Telophase) p. 123
Figure 8-11. Cytokinesis in Plant Cells: ______________________ formation
(Telophase) p. 123
(d) Anaphase: Sister chromatids have separated, and one set has moved toward each pole.
(a) Interphase in a seed cell: Thechromosomes (blue) are in thethin, extended state and appearas a mass in the center of thecell. The spindle microtubules(red) extend outward from thenucleus to all parts of the cell.
(b) Late prophase: The chromosomes (blue) have condensed and attached to the spindle microtubules (red).
(e) Telophase: The chromosomes have gatheredinto two clusters, one at thesite of each future nucleus.
(c) Metaphase: The chromosomeshave moved to the equator of the cell.
(f) Resumption of interphase: Thechromosomes are relaxing againinto their extended state. The spindlemicrotubules are disappearing,and the microtubules of the twodaughter cells are rearranging intothe interphase pattern.
Cell Cycle & Mitosis in a Plant Cell
Mitosis in Whitefish Blastula
WHITEFISH CELLS (MITOSIS)
Mitosis in Onion Root Tip
p. 119
HEALTH WATCH:
CANCER
p. 119
HEALTH WATCH:
CANCER
III. B. Meiosis
1. Chromosome Numbers
homologous pair of chromosomes - similar in size, shape and
_______________________________
diploid (2N) - _____ sets of chromosomes (full
complement)
haploid (N) - _________set of chromosomes
Fig. 8-6
p. 116
The karyotypeof a humanmale
Sex chromosomes
Organisms Chromosome #s
Bacteria 1
Human 46 (23 pairs)
Cat 38
Dog 78
Corn 20
Amoeba 50
Chimpanzee 48
juvenile
fertilized egg
mitotic cell division,differentiation and growth
fusionof gametes
sperm
egg
mitotic cell division, differentiation, and growth
adults
meiotic cell division(in testes)
meiotic cell division(in ovaries)
Fig. 8-8 p. 118
(N)
(2N)
(N)
III. B. 2. The Human Life Cycle
III. B. Meiosis
3. Meiotic Cell Divisions: Meiosis I & II
a) occurs in ___________sex cells (germ cells)
b) produces ______________ gametes that are
genetically ______________________
Fig. 8-12 p. 124
Fig. 8-12 p. 125
Fig. 8-14 Crossing Over (Prophase I)
Fig. 8-13 p. 127
a) The four possible arrangements of homologous pairs at Metaphase I
The 8 possible sets of chromosomes after Metaphase I
III. B. Meiosis
4. Biological Significance
a) Meiosis is the key to ______________
b) __________ reproduction is possible
c) Ensures that the of each species is maintained
throughout generations
III. C. Comparison of Mitosis and Meiosis (in Animal Cells)
Table 8-1 p. 127
Feature Mitosis Meiosis
Cells in which it occurs __________ or body cells Gamete-producing cells
Number of daughter cells 2 , genetically _________ 4 , genetically different
Final chromosome # Diploid Haploid
Number of cell divisions 1 2
Function in animals Development, growth, Gamete production for
repair and maintenance; sexual reproduction
asexual reproduction