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Lesson Overview
Cell Growth, Division, and Reproduction
Lesson Overview
10.1 Cell Growth, Division,
and Reproduction
Lesson Overview
Cell Growth, Division, and Reproduction
Limits to Cell Size
• As cell grows, it is too big for DNA to take care of
(information overload) and it can’t move materials fast
enough
• Ratio of surface area to volume key to cell division
Lesson Overview
Cell Growth, Division, and Reproduction
Division of the Cell
• Before a cell gets too big, it divides into two
new “daughter” cells in a process called cell
division
• Before cell division, the cell copies all of its
DNA so each new cell gets complete set of
“directions”
Lesson Overview
Cell Growth, Division, and Reproduction
Cell Division and Reproduction
Asexual vs. Sexual Reproduction
Asexual reproduction: production of genetically identical offspring
from a single parent; cell division = new organism; ex. binary
fission, budding
Sexual reproduction: offspring inherit some of their genetic
information from each parent; fusion of two cells make offspring;
cell division = growth
http://www.isd622.org/Page/3758
http://www.brainpop.com/science/reproductionandheredity/asexualreproductio
n/preview.weml
Lesson Overview
Cell Growth, Division, and Reproduction
Comparing Sexual and Asexual
Reproduction
Lesson Overview
Cell Growth, Division, and Reproduction
Lesson Overview
10.2 The Process
of Cell Division
http://highered.mcgrawhill.com/sites/0072495855/student_view0/
chapter2/animation__how_the_cell_cycle_
works.html
Lesson Overview
Cell Growth, Division, and Reproduction
Chromosomes
• The genetic information (DNA) that is passed on from
one generation of cells to the next is carried by
chromosomes
• Cells of every organism have a specific number of
chromosomes (human = ??)
Lesson Overview
Cell Growth, Division, and Reproduction
Prokaryotic Chromosomes
Prokaryotic cells chromosomes found in cytosol
Most prokaryotes contain a single, circular DNA
molecule, or chromosome
Lesson Overview
Cell Growth, Division, and Reproduction
The Cell Cycle
During the cell cycle:
•
•
•
the cell grows
it prepares for division
it divides to form two daughter cells
• http://www.youtube.com/watch?v=Q6ucKWIIFmg
• http://outreach.mcb.harvard.edu/animations/cellcycle.swf
Lesson Overview
Cell Growth, Division, and Reproduction
The Prokaryotic Cell Cycle
Binary fission is a form of
asexual reproduction during
which two genetically identical
cells are produced.
For example, bacteria
reproduce by binary fission
Lesson Overview
Cell Growth, Division, and Reproduction
The Eukaryotic Cell Cycle
4 phases of the cell cycle:
G1 – cell increases in size
S – DNA replicated
G2 – makes organelles and
molecules
M – mitosis (nucelar division)
and cytokinesis
Interphase: is the time between
cell divisions
Lesson Overview
Cell Growth, Division, and Reproduction
Important Cell Structures Involved in Mitosis
Chromatid – each strand of a duplicated
chromosome
Centromere – the area where each pair of
chromatids is joined
Centrioles – tiny structures located in the cytoplasm
of animal cells that help organize the spindle
Spindle – a fanlike microtubule structure that helps
separate the chromatids
Lesson Overview
Cell Growth, Division, and Reproduction
Duplicating chromosomes
A cell’s chromosomes are usually long,
thin strands. Just before the cell
divides, however, the chromosomes
become shorter, thicker and more
visible. They are said to condense.
Each chromosome duplicates and becomes two strands,
each one called a chromatid. The two chromatids are
joined at the centromere.
chromatid
condensed
chromosome
centromere
Lesson Overview
Cell Growth, Division, and Reproduction
Mitosis
The 4 phases of mitosis:
1. Prophase
2. Metaphase
3. Anaphase
4. Telophase
http://www.sumanasinc.com/webcontent/animations/content/mitosis.html
Lesson Overview
Cell Growth, Division, and Reproduction
Prophase
• chromosomes condense,
nuclear envelope breaks
down
Lesson Overview
Cell Growth, Division, and Reproduction
Metaphase
• chromosomes line-up
at equator of cell
Lesson Overview
Cell Growth, Division, and Reproduction
Anaphase
• chromatids separate,
move to opposite sides
of cell
Lesson Overview
Cell Growth, Division, and Reproduction
Telophase
• nuclear envelope reforms
around chromatin; forming
2 nuclei
http://www.wwnorton.com/college/biology/disco
verbio3/full/content/ch9/animations.asp
Lesson Overview
Cell Growth, Division, and Reproduction
Cytokinesis
•
Cytokinesis is the division of the cytoplasm; it
completes cell division
•
The process of cytokinesis is different in animal and
plant cells
• Animal cells – cleavage
• Plant cells – cell plate
Lesson Overview
Cell Growth, Division, and Reproduction
Lesson Overview
10.3 Regulating
the Cell Cycle
Lesson Overview
Cell Growth, Division, and Reproduction
Controls on Cell Division
•
The cell cycle is controlled by regulatory proteins both
inside and outside the cell
•
The controls on cell growth and division can be turned
on and off
Lesson Overview
Cell Growth, Division, and Reproduction
The Discovery of Cyclins
Cyclins are a family of proteins that regulate the
timing of the cell cycle in eukaryotic cells
Lesson Overview
Cell Growth, Division, and Reproduction
Regulatory Proteins
Internal regulators are proteins that respond to
events inside a cell
External regulators (ex. growth factors) are
proteins that respond to events outside the cell
Lesson Overview
Cell Growth, Division, and Reproduction
Apoptosis
Apoptosis is a process of programmed cell death.
Apoptosis plays a role in development by shaping the
structure of tissues and organs in plants and animals
Lesson Overview
Cell Growth, Division, and Reproduction
Cancer: Uncontrolled Cell Growth
Cancer is a disorder in which body cells lose the ability to
control cell growth
Cancer cells divide uncontrollably to form a mass of cells
called a tumor
Lesson Overview
TUMORS:
•
benign
•
malignant
Cell Growth, Division, and Reproduction
Lesson Overview
Cell Growth, Division, and Reproduction
What Causes Cancer?
Cancers are caused by defects in genes that regulate
cell growth and division.
Some sources of gene defects are smoking tobacco,
radiation exposure, defective genes (p53), and viral
infection