THE CELL THEORY
All living things are composed of cells.
Cells are the basic units of structure and
function in living things.
New cells are produced from existing
cells.
DNA “overload” – If the cell becomes to
large, the information stored in the DNA
does not meet the cell’s needs.
Surface area to volume ration – Fig. 10-2 –
If the cell becomes to large the surface
area/volume decreases and the exchange
of materials into and out of the cell
becomes more difficult.
Centromere
Chromatid – one of
two identical
“sister” parts of a
duplicated
chromosome
Sister
Chromatids
Centromere – area
where the
chromatids are
attached
Interphase – period
of the cell cycle
between cell
division
G1 – phase in which
cells grow,
synthesize new
proteins and
organelles
S – phase in which
DNA is replicated
G2 – phase in which
molecules and
organelles required
for cell division are
produced
Cell Division/M
phase (Mitosis &
Cytokinesis)
Stages of Mitosis
include prophase,
metaphase,
anaphase, and
telophase
Nuclear membrane
and nucleolus
disappear
Chromatin
condenses into
chromosomes
Spindle fibers form
and centrioles
move to opposite
poles
Chromosomes
attach to spindle
fibers
Chromosomes line
up in the center
Sister chromatids
separate and move
to opposite poles
Spindle fibers
disappear
Chromosomes
uncoil
Nuclear membrane
and nucleolus
reappear
http://www.youtube.com/watch?v=
AhgRhXl7w_g
The following sites are links to various mitosis quizzes
http://www.syvum.com/cgi/online/mult.cgi/squizzes/biology/mito
sis.tdf?0
Cytokinesis is the
fivision of the
cytoplasm, usually
occurs during late
anaphase/early
telophase; each new
cell receives one set
of chromosomes and
half of the organelles
– Fig. 10-6
Animal cells form a
cleavage furrow
Plant cells form a cell
plate that develops
into a new cell wall
When cells
“touch” other
cells they stop
dividing,
therefore, cell
division can be
turned “on” or
“off” – Fig. 10-7
Cell Cycle Regulators
1. cyclins – a family of proteins that regulate
the cell cycle; the amount of these proteins
rise and fall in time with the cell cycle (Fig.
10-8)
2. Internal regulators – responds to events
inside the cell; control when a cell enters
each phase of the cell cycle (cyclins are
examples of internal regulators)
http://www.dnatube.com/video/231/The-CellCycle-Cyclins-and-Checkpoints
Cell Cycle Regulators
3. External regulators – respond to
events outside the cell; controls
speed of cell cycle
a. Embryonic cells divide more
rapidly than the cells of adults
b. Certain cell types divide more
rapidly than others (see analyzing
data pg. 249)
Cancer – uncontrolled cell growth
http://www.mayoclinic.com/health/cancer/MM
00638