Transcript Mitosis ppt

CHAPTER 10
THE CELL
CYCLE
CELL GROWTH
• A LIVING THING GROWS
BECAUSE IT PRODUCES MORE
AND MORE CELLS
• SURFACE AREA OF A CELL DETERMINES
HOW LARGE IT CAN GROW
– SA is critical for passage of food, oxygen,
and water entering and leaving the cell
– As VOLUME increases, SURFACE AREA
decreases
To solve the
problem of
getting too
large, the
cell
DIVIDES
CONTROLS ON CELL
GROWTH
• DEPENDS ON
FUNCTION
– Muscle and nerve cells
don’t divide
– Skin, digestive, and
bone marrow divide
rapidly to replace
those that wear out or
• DEPENDS ON FOOD,
CROWDING, & CONDITIONS IN
SURROUNDING AREA
• IF INJURY OCCURS (CELLS WILL
GROW RAPIDLY AT THE SITE)
• CONSEQUENCES OF
UNCONTROLLED CELL GROWTH
ARE SEVERE
• CANCER CELLS HAVE LOST
THEIR FUNCTION and the
ABILITY TO CONTROL THEIR
GROWTH RATE
Life Span
• Like all organisms, human cells
have a given life span from birth
to death.
• Cells with long life spans don’t
divide.
• Cells with short life spans do
divide.
• Depends on the function of the
cell.
DEFINITIONS
• CELL DIVISION - THE
PROCESS WHEREBY THE
CELL DIVIDES INTO 2
DAUGHTER CELLS
• MITOSIS - PROCESS BY
WHICH THE NUCLEUS OF
A CELL IS DIVIDED INTO
2 NUCLEI; OCCURS IN
SOMATIC (BODY) CELLS
• CHROMOSOMES STRUCTURES IN THE CELL
THAT CONTAIN THE
GENETIC INFORMATION
THAT IS PASSED ON
FROM ONE GENERATION
OF CELLS TO THE NEXT
• CHROMATIN - DNA &
PROTEIN; TIGHTLY
PACKED; APPEARS
GRANULAR; VISIBLE
DURING INTERPHASE
CHROMOSOMES
• THE CELLS OF EVERY
ORGANISM CONTAIN A
SPECIFIC NUMBER OF
CHROMOSOMES
• HUMANS HAVE 23 PAIRS
OR 46 CHROMOSOMES
THE CELL CYCLE
• INTERPHASE --> MADE
UP OF 3 PARTS
• MITOSIS --> MADE UP
OF 4 PARTS
• CYTOKINESIS --> MADE
UP OF 1 PART
Nuclear
Division
Growth to
prepare for
mitosis
Cell
Growth
DNA replication
D. Mitosis
C.
Growth
(G2)
A.
Growth
(G1)
B. DNA
Synthesis
INTERPHASE
Interphase
INTERPHASE
• A. G1
CELLULAR
GROWTH AND
DEVELOPMENT
TAKES PLACE
INTERPHASE
• B. DNA
SYNTHESIS
(S)
DNA IS
REPLICATED
INTERPHASE
• C. GAP 2 (G2)
SYNTHESIS
OF
ORGANELLES
(SHORTEST
PART OF
INTERPHASE)
MITOSIS
• The process where one large
cell becomes two identical
smaller cells
• Organisms do this for growth,
repair, or Asexual Reproduction
PHASES OF
MITOSIS
• PROPHASE
– CENTRIOLE
S SEPARATE
FROM EACH
OTHER AND
MOVE TO
THE POLES
PROPHASE
• NUCLEAR
ENVELOPE
BREAKS
DOWN AND
NUCLEOLUS
DISAPPEARS
PROPHASE (early)
• CHROMATIN COILS
UP AND BECOMES
VISIBLE AS
CHROMOSOMES
Early Prophase
PROPHASE (late)
• CHROMOSOMES BECOME
ATTACHED TO THE
SPINDLE FIBERS AT THE
CENTROMERE
• SPINDLE FIBERS – FANLIKE
MICROTUBULE STRUCTURE
THAT SEPARATES THE
CHROMOSOMES
Late Prophase
SPINDLE
FIBERS
CENTROMERE
CENTRIOLE
S
CHROMOSOMES
Prophase
METAPHASE
• CHROMOSOMES
LINE UP ACROSS
THE EQUATOR
(CENTER) OF THE
CELL
Metaphase
Metaphase
Metaphase
ANAPHASE
• CENTROMERES SPLIT
CAUSING THE SISTER
CHROMATIDS TO
SEPARATE, BECOMING
INDIVIDUAL
CHROMOSOMES
– CONTINUE TO MOVE IN 2
GROUPS NEAR THE POLES
Anaphase
Anaphase
Anaphase
Anaphase
TELOPHASE
• CHROMOSOMES UNCOIL
INTO TANGLE OF
CHROMATIN
Telophase
Telophase
Telophase
TELOPHASE
• NUCLEAR ENVELOPE
REFORMS AROUND
CHROMATIN
– NUCLEOLUS BECOMES
VISIBLE AGAIN
CYTOKINESIS
• DIVISION OF THE
CYTOPLASM INTO THE 2
DAUGHTER CELLS
CYTOKINESIS
• Last part of the cell cycle
• Cytoplasm divides into 2
daughter cells
• In animals, the membrane
folds in to form the
cleavage furrow
• Plants - Cell plate forms
Cleavage Furrow
Two Identical Daughter
Cells
•
•
•
•
•
•
SHORTCUT TO REMEMBER
THE CELL CYCLE
I nterphase
P rophase
M etaphase
A naphase
T elophase
C ytokinesis
•
•
•
•
•
•
I
Played
Marbles
At
Taco
Cabana
SHORTCUT TO REMEMBER
MITOSIS
• Pass Me A Taco:
–Prophase
–Metaphase
–Anaphase
–Telophase
Animation of Mitosis
• http://www.sci.sdsu.edu/multimedia/mitosi
s/mitosis_gif1.html
• http://www.loci.wisc.edu/outreach/bioclips/
CDBio.html