Transcript Chapter 10.2 The Cell Cycle Mitosis

Chapter 10.2
Section 2 The Cell Cycle
Objectives
• Identify the major events that characterize each of
the five phases of the cell cycle.
• Describe the structure and function of the spindle
during mitosis.
• Summarize the events of the four stages of mitosis.
• Differentiate cytokinesis in animal and plant cells.
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Chapter 10.2
New Vocabulary
•
•
•
•
•
Cell Cycle
Interphase
Mitosis
Cytokinesis
Cancer
•
•
•
•
•
•
Spindle
Prophase
Metaphase
Anaphase
Telophase
Cell plate
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Chapter 10.2
Section 2 The Cell Cycle
• The life of a eukaryotic
cell is often depicted as
a _________
cycle
• The cell cycle is a
repeating sequence of
growth and
cellular _________
________________
division
during the life of an
organism
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Chapter 10.2
Section 2 The Cell Cycle
• A cell spends _____
90%
percent of its time in
the first three phases of
the cycle, which are
collectively called
Interphase
_________________
– ______
G1
– ______
S
– _____
G2
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Chapter 10.2
Section 2 The Cell Cycle
G1 Phase (Gap 1)
• A period of
rapid growth
___________
• The cell carries out all
routine
of its ____________
functions
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Chapter 10.2
remain in the G1
• Cells that are not dividing ___________
phase
– Example:
• After you are developed some of your
nerve
muscle
_____________
and _______________
cells
stop dividing and replicating…so it is important
to take care of them
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Chapter 10.2
G0
• If a cell no longer
divides, sometimes
scientist say that it is
G0 stage,
in the ______
because it has left the
cell cycle
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Chapter 10.2
Section 2 The Cell Cycle
S Phase
• Period during which DNA is
copied or
__________
______________
synthesized
• To be copied, the DNA must
stretched out, so it is
be ___________
chromatin
called ______________
• The two identical copies will
chromatids
form the _______________
in a chromosome
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Chapter 10.2
Section 2 The Cell Cycle
G2 Phase (Gap 2)
• Other organelles
necessary for
reproduction, such as
spindle
___________
fibers,
are made
– They consist of
microtubules
_______________
that pull apart the
_______________
chromatids
of chromosomes so
that they can be
divided between
new cells
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Chapter 10.2
Section 2 The Cell Cycle
• After interphase,
mitosis
_______________
occurs, which is
sometimes called the
M phase
_____
• During mitosis, the
copied DNA coils up
into ______________
chromosomes
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Chapter 10.2
• These chromosomes, are passed onto each new cell
nuclear
when the cell divides…but the ______________
________________
must first disintegrate.
envelope
reforms
– A new nucleus _______________
in each new
cell
– Due to this occurrence, mitosis is often referred to
as ________________
division
nuclear
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Chapter 10.2
Section 2 The Cell Cycle
• After mitosis,
cytokinesis
_________________
occurs
• Cytokinesis involves
the splitting of the
cytoplasm
_________________
• Once cytokinesis is
complete, the original
cell has divided into
2
_______
new,
identical cells
_____________
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Chapter 10.2
Review
• What occurs in the following three phases of
interphase….
– G1
Growth and normal activities
–S
DNA synthesis
– G2
synthesis or replication of organelles
needed for division
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Chapter 10.2
copied
• Once cells pass the G1, DNA is ________________
• Each copy of the DNA is then separated into _____
two
mitosis
new cells through the process of _______________
• Chromosomes are actually pulled apart with the help
of a ________________
spindle
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Chapter 10.2
Spindle Structure
• A spindle consist of
centrioles
________________
and
individual ____________
fibers
which are made up of
microtubules
_______________
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Chapter 10.2
9 triplets of microtubules that
• Centrioles consist of ____
arranged in a circle
Animal
• ___________
cells always
contain ____
1
pair of
centrioles, but
they are
replicated
during the
______
G2 phase
of interphase
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Chapter 10.2
• At the beginning of mitosis, the centrioles move to
areas on the opposite poles of the cell called
__________________
centrosomes
• The centrosome
organizes the
formation of the
spindle
____________
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Chapter 10.2
• As the centrioles move, the spindle fibers begin to form
and _____________
towards the chromosomes
extend
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Chapter 10.2
• Scientists are unclear about the role of centrioles in
cell division, because they are not necessary for
spindle _________________
formation
• Plant cells, which do not have centrioles, form a
identical
spindle that is almost _________________
to those
in animal cells
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Chapter 10.2
Section 3 Mitosis and Cytokinesis
Separation of Chromatids
chromatids that make up a
• The two _______________
chromosome are moved to each pole of the cell in a
manner similar to bringing in a fish with a fishing rod
reel
and ___________
• When the microtubule “fishing line” is “reeled in,” the
dragged
chromatids are ______________
to opposite poles.
• When the chromatids separate, you may call each
one a _________________
chromosome
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Chapter 10.2
4 continuous
• Mitosis actually occurs in ______
phases…
– _______________________
(P)
Prophase
Metaphase
– _______________________
(M)
Anaphase
– _______________________
(A)
Telophase
– _______________________
(T)
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Chapter 10.2
Prophase
chromosomes
• Chromatin condenses into visible _______________
dissolves
• Nuclear envelope _________________
• Centrioles move
towards opposite
______________
and
poles
the ____________
spindle
forms
nucleus
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Chapter 10.2
Metaphase
• Chromosomes line up along the middle or
equator of the cell
____________
• Spindle fibers attach to
the centromere region
that hold the sister
chromatids
_______________
together
– Specifically, they
attach to a protein
complex called a
kinetochore
________________
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Chapter 10.2
Anaphase
Centromeres divide as spindle fibers pull the
• _________________
chromatids apart
• The chromatids can
now be called
________________
chromosomes
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Chapter 10.2
Telophase
reforms
• Nuclear envelope ______________
dissolves
• Spindle __________
• Chromosomes begin
to uncoil and stretch
back into
chromatin
______________
• Reverse of
prophase
______________
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Chapter 10.2
Section 2 Mitosis and Cytokinesis
Cytokinesis
• As mitosis ends, cytokinesis occurs.
• During cytokinesis…
half
– the cytoplasm of the cell is divided in __________
– and the cell membrane grows to __________
separate
each cell
– ____,
2 identical separate cells are formed
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Chapter 10.2
Section 2 Mitosis and Cytokinesis
• In animal cells,
cytokinesis actually
begins during
anaphase
_______________
• A belt of protein
fibers
__________
pinches
the cell in half
• This indentation is
furrow
called a ___________
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Chapter 10.2
• In plant cells, vesicles
cellulose
containing ____________
begin to congregate
between the two nuclei
• These vesicles begin to
fuse, forming a cell
membrane while
_______________,
the cellulose is used to
wall
form a cell __________
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Chapter 10.2
• As the new cell wall forms
in between the cell
membranes, this structure
plate
is called a cell _________
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Chapter 10.2
• Recall Question?
– What cell part actually makes the vesicles?
• Hint…it is the packager and shipper
Golgi apparatus
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Chapter 10.2
Objective 1
• Identify the major events that characterize each
of the five phases of the cell cycle
– G1
Growth and normal cell activities
– S
Synthesis of DNA
– G2
Replication of organelles
– Mitosis
Splitting of the nucleus
– Cytokinesis
Splitting of the cytoplasm
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Chapter 10.2
• End result of mitosis?
– A diploid parent cell has been divided into two,
diploid
identical ____________
daughter cells
• These new cells are small and will begin to grow
during the _____
G1 phase of interphase
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Chapter 10.2
Objective 1
• Describe the structure and function of the spindle
during mitosis.
The spindle consists of fibers that
attach to and move chromosomes
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Chapter 10.2
Objective 2
•
Summarize the events of the four stages of mitosis.
Breakdown of nucleus, chromosomes
condense, spindle forms
Metaphase Chromosomes line up at the middle or
equator
Anaphase Chromatids are split
Prophase
Telophase Nucleus reforms…2 new cells have
been formed, chromosomes uncoil,
spindle dissolves
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Chapter 10.2
Objective 3
• Differentiate cytokinesis in animal and plant cells.
Protein belt pinches
in the dividing cell
forming a cleavage
furrow
Vesicles containing
cellulose create a
cell plate
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